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LTM4680

Rev. B

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APPLICATIONS INFORMATION

CHECKING TRANSIENT RESPONSE

The regulator loop response can be checked by looking at

the load current transient response. Switching regulators

take several cycles to respond to a step in DC (resistive)

load current. When a load step occurs, V

OUT

shifts by an

amount equal to ∆I

LOAD(ESR)

, where ESR is the effective

series resistance of C

OUT

. ∆I

LOAD

also begins to charge or

discharge C

OUT

generating the feedback error signal that

forces the regulator to adapt to the current change and

return V

OUT

to its steady-state value. During this recov-

ery time V

OUT

can be monitored for excessive overshoot

or ringing, which would indicate a stability problem. The

availability of the COMP pin not only allows optimization

of control loop behavior but also provides a DC-coupled

and AC-filtered closed-loop response test point. The DC

step, rise time and settling at this test point truly reflects

the closed-loop response. Assuming a predominantly

second order system, phase margin and/or damping fac-

tor can be estimated using the percentage of overshoot

seen at this pin. The bandwidth can also be estimated by

examining the rise time at the pin. The COMP

a external

capacitor shown in the Typical Application circuit will pro-

vide an adequate starting point for most applications. The

programmable parameters that affect loop gain are the

voltage range, bit[1] of the MFR_PWM_MODE command,

the current range bit[7] of the MFR_PWM_MODE com-

mand, the g

of the PWM channel amplifier bits [7:5] of

MFR_PWM_COMP, and the internal R

COMP

compensation

resistor, bits[4:0] of MFR_PWM_COMP. Be sure to estab-

lish these settings prior to compensation calculation.

The COMP

a series internal R

COMP

and external C

COMP

filter sets the dominant pole-zero loop compensation.

The internal R

COMP

value can be modified (from 0Ω to

62kΩ) using bits[4:0] of the MFR_PWM_ COMP com-

mand. Adjust the value of R

COMP

to optimize transient

response once the final PCB layout is done and the par-

ticular C

COMP

filter capacitor and output capacitor type

and value have been determined. The output capacitors

need to be selected because the various types and values

determine the loop gain and phase. An output current

pulse of 20% to 80% of full-load current having a rise

time of 1µs to 10µs will produce output voltage and COMP

pin waveforms that will give a sense of the overall loop

stability without breaking the feedback loop. Placing a

power MOSFET with a resistor to ground directly across

the output capacitor and driving the gate with an appro-

priate signal generator is a practical way to produce to a

load step. The R

SERIES

will produce output cur-

rents approximately equal to V

OUT

SERIES

. R

SERIES

val-

ues from 0.1Ω to 2Ω are valid depending on the current

limit settings and the programmed output voltage. The

initial output voltage step resulting from the step change

in output current may not be within the bandwidth of the

feedback loop, so this signal cannot be used to determine

phase margin. This is why it is better to look at the COMP

pin signal which is in the feedback loop and is the filtered

and compensated control loop response. The gain of the

loop will be increased by increasing R

COMP

. If R

COMP

increased by the same factor that C

COMP

is decreased,

the zero frequency will be kept the same, thereby keeping

the phase shift the same in the most critical frequency

range of the feedback loop. The gain of the loop will be

proportional to the transconductance of the error ampli-

fier which is set using bits[7:5] of the MFR_PWM_COMP

command. The output voltage settling behavior is related

to the stability of the closed-loop system and will demon-

strate the actual overall supply performance. A second,

more severe transient is caused by switching in loads with

large (>1µF) supply bypass capacitors. The discharged

bypass capacitors are effectively put in parallel with C

OUT

causing a rapid drop in V

OUT

. No regulator can alter its

delivery of current quickly enough to prevent this sudden

step change in output voltage if the load switch resistance

is low and it is driven quickly. If the ratio of C

LOAD

Figure 29. R

COMP

Adjust

INCREASE R

COMP

FREQUENCY

4680 F29

GAIN

TYPE II COMPENSATION

Содержание ANALOG DEVICES LTM4680

Страница 1: ...2 5 Current Readback Accuracy 25 C to 125 C n n Integrated Input Current Sense Amplifier n n 400kHz PMBus Compliant I2C Serial Interface n n Supports Telemetry Polling Rates up to 125Hz n n Constant...

Страница 2: ...ing Not Applicable if MFR_ CONFIG_ALL 6 1b 31 Table 3 FSWPH_CFG Pin Strapping Look Up Table to Set the LTM4680 s Switching Frequency and Channel Phase Interleaving Angle Not Applicable if MFR_CONFIG_A...

Страница 3: ...5A s Slew Rate 66 Table 13 Channel Output Voltage vs Capacitor Selection Bulk and Ceramic Cap Configuration 15A to 30A Load Step with 15A s Slew Rate 67 Table 14 Dual Phase Single Output Voltage vs Ca...

Страница 4: ...GND GND VOUT0 GND INTVCC VDD33 FSWPH_ CFG VOUT0_ CFG SHARE CLK VOUT1_ CFG VTRIM1_ CFG EXTVCC GND RUN1 PGOOD1 PGOOD0 VOSNS0 VOSNS0 TOP VIEW BGA PACKAGE 144 LEAD 16mm 16mm 7 82mm TJMAX 125 C JCtop 3 3...

Страница 5: ...uous Mode Operation Discontinuous Mode MFR_PWM_MODEn 0 0b IOUTn 100mA 20 mA IS VINn FCM Input Supply Current in Forced Continuous Mode Operation Forced Continuous Mode MFR_PWM_MODEn 0 1b VINn 12V VOUT...

Страница 6: ...its mV RVSNS0 VOSNS0 Impedance to SGND 0 05V VVOSNS0 VSGND 3 3V 50 k RVSNS1 VOSNS1 Impedance to SGND 0 05V VVOSNS1 VSGND 3 3V 50 k tON MIN Minimum On Time Note 8 60 ns RCOMP0 1 Resolution Compensation...

Страница 7: ...Driven from 8 775V to 9 225V VIN_OFF 9V SVIN Driven from 9 225V to 8 775V l l 100 100 s s tPROP SVIN LOW VIN SVIN OV UV Comparator Response Time Low VIN Operating Configuration Test Circuit 2 and VIN...

Страница 8: ...V VIIN VIIN 5mV Gain 4 0V VIIN VIIN 20mV Gain 2 0V VIIN VIIN 50mV 15 26 30 52 61 V V V IIN_TUE Total Unadjusted Error Gain 8 2 5mV VIIN VIIN Note 14 Gain 4 4mV VIIN VIIN Note 14 Gain 2 6mV VIIN VIIN N...

Страница 9: ...YNC Low Output Voltage ILOAD 3mA 0 2 0 4 V ILEAK SYNC SYNC Leakage Current in Slave Mode 0V VPIN 3 6V 5 A SYNC 0 SYNC to Ch0 Phase Relationship Based on the Falling Edge of Sync and Rising Edge of TG0...

Страница 10: ...DAT Date Hold Time Receiving Data Transmitting Data l l 0 0 3 0 9 s s tSU DAT Data Setup Time Receiving Data 0 1 s tTIMEOUT_SMB Stuck PMBus Timer Non Block Reads Stuck PMBus Timer Block Reads Measure...

Страница 11: ...esenting a signed exponent to be raised to the power of 2 and 11 least significant bits representing a signed mantissa input voltage on SVIN accessed via the READ_VIN command code output currents IOUT...

Страница 12: ...350kHz 1 5V 425kHz 1 8V 500kHz 2 5V 575kHz 3 3V 650kHz LOAD CURRENT A 0 5 10 15 20 25 30 65 70 75 80 85 90 95 100 EFFICIENCY 4680 G01 0 9V 250kHz 1 0V 250kHz 1 2V 350kHz 1 5V 425kHz 1 8V 500kHz 2 5V...

Страница 13: ...P 17k EA GM 3 69ms COMPna 3 3nF COMPnb 68pF ILIM LOW VOUT RANGE LOW 4680 G07 50mV DIV LOAD STEP 10A DIV 100 s DIV FIGURE 46 CIRCUIT 12V TO 2 5V FREQ 575kHz COUT 470 F 2 POSCAP 100 F 4 CERAMIC RCOMP 20...

Страница 14: ...G17 30 7 30 9 31 0 30 9 30 5 30 8 31 2 READ_IOUT CHANNEL READBACK A 29 8 29 9 NUMBER OF CHANNELS 4 1 3 2 0 30 1 30 3 30 0 30 2 4680 G18 30 0 30 3 30 3 29 9 30 2 30 6 READ_IOUT CHANNEL READBACK A 29 4...

Страница 15: ...Negative Differential Voltage Sense Input See VOSNS1 SGND F9 10 G9 10 SGND is the signal ground return path of the LTM4680 SGND is not internally connected to GND Connect SGND to GND local to the LTM...

Страница 16: ...d PGOODn No external decoupling is required VDD25 D12 Internally Generated 2 5V Power Supply Output Pin Do not load this pin with external current it is used strictly to bias internal logic and provid...

Страница 17: ..._CFG and VTRIM1_CFG pins are both left open or if the LTM4680 is con figured to ignore pin strap RCONFIG resistors i e MFR_CONFIG_ALL 6 1b then the LTM4680 s target VOUT1 output voltage setting VOUT_C...

Страница 18: ...L 1 0b clock stretching disabled If communication on the bus at clock speeds above 100kHz is required the user s SMBus master s needs to implement clock stretching support to assure solid serial bus c...

Страница 19: ...FG VOUT0_CFG VOUT1_CFG FSWPH_CFG 2 5V DIGITAL ENGINE 3 3V TOLERANT PULL UP NOT SHOWN CONFIG RESISTORS TO 2 5V SGND NOT SHOWN ASEL SCL SDA ALERT WP RUN0 RUN1 FAULT0 FAULT1 SHARE_CLK 5 5V TOLERANT PULL...

Страница 20: ...T SHOWN DCR SENSE Z CCM CH0 I SIGNAL CCM CH1 I SIGNAL OPTIONAL SNUBBER OPTIONAL SNUBBER SV IN TELEMETRY MFR_READ_ICHIP READ_VIN READ_VIN_PEAK CURRENT MODE PWM CNTL LOOPS POWER CONTROL ANALOG SECTION L...

Страница 21: ...VIN1 COMP0b VTRIM1_CFG VOSNS1 VTRIM0_CFG VOUT0_CFG VOUT1 ALERT SHARE_CLK VOUT1_CFG GND SVIN VOSNS1 TSNS0a TSNS0b SGND TSNS1a TSNS1b FSWPH_CFG ASEL IN IN LTM4680 2 2 F 150 F I2 C SMBus I F WITH PMBus...

Страница 22: ...COMP0b VTRIM1_CFG VOSNS1 VTRIM0_CFG VOUT0_CFG VOUT1 ALERT SHARE_CLK VOUT1_CFG GND SVIN VOSNS1 TSNS0a TSNS0b SGND TSNS1a TSNS1b FSWPH_CFG ASEL IN IN LTM4680 2 2 F 150 F 1 I2 C SMBus I F WITH PMBus COMM...

Страница 23: ...Both Channels VOUT0 VOUT1 Both Programmable Up to 3 6V n Power Up and Program EEPROM with EXTVCC n Input Voltage Up to 16V n VBE Temperature Sensing n SYNC Contention Circuit Refer to Frequency and Ph...

Страница 24: ...ations All EEPROM write operations will be re enabled when the die temperature drops below 125 C The controller will also disable all the switching when the die temperature exceeds the internal overte...

Страница 25: ...Compensation section The LTM4680 module has sufficient stability margins and good transient performance with a wide range of output capacitors even all ceramic MLCCs Table 12 through Table 14 provide...

Страница 26: ...le digitally ramping the target voltage from 0V to the com manded voltage set point Once the LTM4680 is com manded to turn on after power up and initialization the controller waits for the user specif...

Страница 27: ...ion mode Mode selection is done using the MFR_PWM _MODE command discontinuous conduc tion is always the start up mode forced continuous is the default running mode If a controller is enabled for disco...

Страница 28: ...an also be set from EEPROM or external configuration resistors as outlined in Table 3 Designated phase is the relation ship between the falling edge of SYNC and the internal clock edge that sets the P...

Страница 29: ...uit to maintain an essentially constant current limit with temperature The current sensed is then digitized by the LTM4680 s telemetry ADC with an input range of 128mV a noise floor of 7 VRMS and a pe...

Страница 30: ...rse settings If the pin is open the VOUT_ COMMAND command is loaded from NVM to determine the output voltage The default setting is to have the switcher off unless the voltage configuration pins are i...

Страница 31: ...cation could also affect RVOUTn_CFG s value over time All such effects must be taken into account in order for resistor pin strapping to yield the expected result at every SVIN power up and or every e...

Страница 32: ...ternal 90 270 001b 1b 0 787 External 0 180 000b 1b 0 External 120 240 100b 1b RFSWPH_CFG value indicated is nominal Select RFSWPH_CFG from a resistor vendor such that its value is always within 3 of t...

Страница 33: ...ommand Examples Expressed in 7 and 8 Bit Addressing DESCRIPTION HEX DEVICE ADDRESS BIT 7 BIT 8 BIT 7 6 5 4 3 2 1 0 R W Rail4 0x5A 0xB4 0 1 0 1 1 0 1 0 0 Global4 0x5B 0xB6 0 1 0 1 1 0 1 1 0 Default 0x4...

Страница 34: ...S_BYTE and STATUS_WORD commands also summarize contents of other status registers Refer to PMBus Command Details for specific information NONE OF THE ABOVE in the STATUS_BYTE indicates that one or mor...

Страница 35: ...5 4 3 2 1 0 STATUS_CML 7 6 5 4 3 2 1 0 STATUS_VOUT 7 6 5 4 3 2 1 0 PAGED STATUS_IOUT 7 6 5 4 3 2 1 0 PAGED VOUT_OV Fault VOUT_OV Warning VOUT_UV Warning VOUT_UV Fault VOUT_MAX Warning TON_MAX Fault TO...

Страница 36: ...f a CRC error occurs the CML bit is set in the STATUS_BYTE and STATUS_WORD commands the appropriate bit is set in the STATUS_MFR_SPECIFIC command and the ALERT pin will be pulled low NVM repair can be...

Страница 37: ...e VOUT if Using the Resistor Configuration Pins n In NVM if Either Programmed at the Factory or Through the GUI n By PMBus Command The IIN and IOUT overcurrent monitors are performed by ADC readings a...

Страница 38: ...FAULT_LIMIT time is started after TON_DELAY has been reached and a SOFT_START sequence is started The resolution of the TON_MAX_ FAULT_LIMIT is 10 s If the VOUT_UV_FAULT _LIMIT is not reached within t...

Страница 39: ...updated buffer in RAM When a fault event occurs the fault log buffer is copied from the RAM buffer into NVM Fault logging is allowed at tem peratures above 85 C however retention of 10 years is not gu...

Страница 40: ...ces between SMBus and I2C refer to System Management Bus SMBus Specification Version 2 0 Appendix B Differences Between SMBus and I2C PMBus SERIAL DIGITAL INTERFACE The LTM4680 communicates with a hos...

Страница 41: ...ITION EXAMPLE TERMINOLOGY SPECIFICATION REFERENCE L11 Linear Part II 7 1 Linear_5s_1s Floating point 16 bit data value Y 2N where N b 15 11 and Y b 10 0 both two s compliment binary integers b 15 0 0x...

Страница 42: ...COMMAND CODE PEC Wr A A A P 4680 F10 S 7 8 8 1 1 1 1 1 1 SLAVE ADDRESS COMMAND CODE DATA BYTE Wr A A A P S 7 8 8 1 1 1 1 1 1 F11 SLAVE ADDRESS COMMAND CODE DATA BYTE Wr A A A P 4680 F12 S 7 8 8 1 PEC...

Страница 43: ...COMMAND CODE SLAVE ADDRESS Wr A A A P A 4680 F18 S 7 8 7 1 DATA BYTE LOW 8 DATA BYTE HIGH PEC 8 8 1 1 1 1 1 1 1 1 Sr 1 A 1 Rd A SLAVE ADDRESS COMMAND CODE SLAVE ADDRESS Wr A A Sr S 7 8 7 1 1 BYTE COUN...

Страница 44: ...LAVE ADDRESS COMMAND CODE BYTE COUNT M Wr A A S 7 8 8 1 DATA BYTE 1 8 1 1 1 1 1 A A A DATA BYTE 2 8 1 A DATA BYTE M 8 1 SLAVE ADDRESS BYTE COUNT N Rd A A Sr 7 8 DATA BYTE 1 8 1 1 1 1 1 1 A A DATA BYTE...

Страница 45: ...usy errors and simplify error handling software while ensur ing robust communication and system behavior Please refer to the subsection titled PMBus Communication and Command Processing in the Applica...

Страница 46: ...4 Output undervoltage fault limit R W Word Y L16 V Y 0 9 0x0E66 88 VOUT_UV_FAULT_ RESPONSE 0x45 Action to be taken by the device when an output undervoltage fault is detected R W Byte Y Reg Y 0xB8 97...

Страница 47: ...status R W Byte Y Reg NA 109 STATUS_IOUT 0x7B Output current fault and warning status R W Byte Y Reg NA 110 STATUS_INPUT 0x7C Input supply fault and warning status R W Byte N Reg NA 110 STATUS_TEMPER...

Страница 48: ...Y 0x28 83 MFR_PWM_MODE 0xD4 Configuration for the PWM engine R W Byte Y Reg Y 0x47 82 MFR_FAULT_RESPONSE 0xD5 Action to be taken by the device when the FAULT pin is externally asserted low R W Byte Y...

Страница 49: ...element in m R W Word N L11 m Y 1000 0x03E8 86 MFR_TEMP_1_GAIN 0xF8 Sets the slope of the external temperature sensor R W Word Y CF Y 0 995 0x3FAE 92 MFR_TEMP_1_OFFSET 0xF9 Sets the offset of the ext...

Страница 50: ...two s complement exponent that is hardwired to 12 decimal Example For b 15 0 0x9800 b1001_1000_0000_0000 Value 19456 2 12 4 75 From PMBus Spec Part II Paragraph 8 2 Reg Register PMBus data field b 15...

Страница 51: ...bulk output capacitors defined as COUT are chosen with low enough effective series resistance ESR to meet the output volt age ripple and transient requirements COUT can be a low ESR tantalum capacito...

Страница 52: ...ould be configured as sync slaves The most straightforward way is to set its FREQUENCY_ SWITCH command to 0x0000 and MFR_CONFIG_ ALL 4 1b This can be easily implemented with resistor pin strap setting...

Страница 53: ...ificantly different operation at the higher of the two recommended switching frequencies is preferable but minimum on time must be considered See Minimum On Time Considerations section Table 9 Recomme...

Страница 54: ...ency thus the actual time delays will have some variance Soft start is performed by actively regulating the load voltage while digitally ramping the target voltage from 0V to the commanded voltage set...

Страница 55: ...N pin goes low or if the part is commanded off If the part faults off or FAULTn is pulled low externally and the part is programmed to respond to this the output will three state rather than exhibitin...

Страница 56: ...t of commands global address 0x5B command 0xBD data 0x2B followed by global address 0x5B command 0xBD and data 0xC4 The part will now respond to the cor rect address Configure the part as desired then...

Страница 57: ...1 s The RC time constant should be approximately 3 s or faster PHASE LOCKED LOOP AND FREQUENCY SYNCHRONIZATION The LTM4680 has a phase locked loop PLL comprised of an internal voltage controlled osci...

Страница 58: ...To com pensate for this voltage drop the MFR_RVIN will be automatically set to the 1 internal sense resistor in the Figure 2 Block Diagram The LTM4680 will multiply the MFR_READ_ICHIP measurement valu...

Страница 59: ...icular CCOMPnb filter capacitor and output capacitor type and value have been determined The output capacitors need to be selected because the various types and values determine the loop gain and phas...

Страница 60: ...ivalent can be interfaced to the LTM4680 on the user s board for programming telemetry and system debug The adapter when used in conjunction with LTpowerPlay provides a powerful way to debug an entire...

Страница 61: ...including the DC2844A demo board the DC2298A socketed programming board or a customer target system The software also provides an automatic update feature to keep the revisions current with the latest...

Страница 62: ...TION Figure 31 LTpowerPlay Screen Shot DECODER CMD INTERNAL PROCESSOR WRITE COMMAND DATA BUFFER PAGE CMDS 0x00 0x21 0xFD 4680 F32 x1 MFR_RESET VOUT_COMMAND S CALCULATIONS PENDING PMBus WRITE R FETCH C...

Страница 63: ...f dealing with busy behavior and unwanted ALERT notification A simple way to achieve this is to create a SAFE_WRITE_BYTE and SAFE_WRITE_ WORD subroutine The above polling mechanism allows your softwar...

Страница 64: ...application to operate such that most of the heat flows from the junction to the top of the part As in the case of JCbottom this value may be useful for comparing packages but the test condi tions don...

Страница 65: ...TM4680 with various heat sinking and airflow conditions These thermal resistances represent demonstrated performance of the LTM4680 on hardware a 6 layer FR4 PCB measuring 99mm 130mm 1 6mm using 2oz c...

Страница 66: ...e 68 3 3 11 5 04 250 15 to 30 104 40 15 1 Low Low 330 FX7 None 68 3 3 11 5 04 250 15 to 30 105 40 5 0 9 Low Low 330 FX6 None 68 3 3 9 5 76 350 15 to 30 102 30 12 0 9 Low Low 330 FX6 None 68 3 3 9 5 76...

Страница 67: ...3 3 17 3 69 350 15 to 30 104 50 15 1 Low Low 100 FX4 470 FX2 68 3 3 17 3 69 350 15 to 30 104 50 5 1 2 Low Low 100 FX4 470 FX2 68 3 3 17 3 69 350 15 to 30 107 50 12 1 2 Low Low 100 FX4 470 FX2 68 3 3 1...

Страница 68: ...91 7 30 12 1 Low Low 100 Fx8 470 Fx4 68 3 3 15 3 69 350 30 to 60 87 7 30 15 1 Low Low 100 Fx8 470 Fx4 68 3 3 15 3 69 350 30 to 60 87 30 6 1 5 Low Low 100 Fx8 470 Fx4 68 3 3 15 3 69 425 30 to 60 89 30...

Страница 69: ...250kHz 1 2V 350kHz 1 5V 425kHz 1 8V 500kHz 2 5V 575kHz 3 3V 650kHz LOAD CURRENT A 0 10 20 30 40 50 60 0 2 4 6 8 10 12 POWER LOSS W 4680 F36 0 9V 250kHz 1 0V 250kHz 1 2V 350kHz 1 5V 425kHz 1 8V 500kHz...

Страница 70: ...ttenuation SAFETY CONSIDERATIONS The LTM4680 modules do not provide galvanic isolation from VIN to VOUT There is no internal fuse If required a slow blow fuse with a rating twice the maximum input cur...

Страница 71: ...4 Recommended PCB Layout Package Top View n For parallel modules tie the VOUTn VOSNSn VOSNSn voltage sense differential pair lines RUNn COMPna COMPnb pin together The user must share the SYNC SHARE_CL...

Страница 72: ...TRIM1_CFG VOSNS1 VTRIM0_CFG VOUT0_CFG VOUT1 ALERT SHARE_CLK VOUT1_CFG GND SVIN VOSNS1 TSNS0a TSNS0b SGND TSNS1a TSNS1b FSWPH_CFG ASEL IN IN LTM4680 10k 10k 10k 10k 4 99k 22 6k 5 75V TO 16V ON OFFCONFI...

Страница 73: ...OUT0_CFG VOUT1 ALERT SHARE_CLK VOUT1_CFG GND SVIN VOSNS1 TSNS0a TSNS0b SGND TSNS1a TSNS1b FSWPH_CFG ASEL IN IN LTM4680 10k 10k 10k 10k 10k 10k 4 99k 10k CSNUB0 RSNUB0 RSNUB1 CSNUB1 22 6k LOAD0 I2 C SM...

Страница 74: ...OOD VOSNS0 VOSNS0 FAULT0 FAULT1 V DD33 V DD25 WP SYNC VIN0 INTV CC VOUT0 SCL SDA RUN0 RUN1 EXTV CC SW0 SW1 COMP1a COMP1b PGOOD0 PGOOD1 COMP0a VIN1 COMP0b VTRIM1_CFG VOSNS1 VTRIM0_CFG VOUT0_CFG VOUT1 A...

Страница 75: ...YNC VIN0 INTV CC VOUT0 SCL SDA RUN0 RUN1 EXTV CC SW0 SW1 COMP1a COMP1b PGOOD0 PGOOD1 COMP0a VIN1 COMP0b VTRIM1_CFG VOSNS1 VTRIM0_CFG VOUT0_CFG VOUT1 ALERT SHARE_CLK VOUT1_CFG GND SVIN VOSNS1 TSNS0a TS...

Страница 76: ...MBus COMMAND SET TO FROM IPMI OR OTHER BOARD MANAGEMENT CONTROLLER 5 75V TO 16V ON OFF FAULTS CONFIG RESISTORS ARE TO BE 1 50PPM CONFIG RESISTORS ARE TO BE 1 50PPM SYNC SHARE CLK VDD33 U1 U1 VDD33 U1...

Страница 77: ...Setting PAGE to 0xFF applies any following paged commands to both outputs With PAGE set to 0xFF the LTM4680 will respond to read commands as if PAGE were set to 0x00 Channel 0 results This command has...

Страница 78: ...This command does not indicate the status of the WP pin which is defined in the MFR_COMMON command The WP pin takes precedence over the value of this command BYTE MEANING 0x80 Disable all writes exce...

Страница 79: ...cations fault Setting this command to a value of 0x80 disables rail device addressing for the channel This command has one data byte GENERAL CONFIGURATION COMMANDS COMMAND NAME CMD CODE DESCRIPTION TY...

Страница 80: ...xpired the PWM channel will proceed to the TON_DELAY state and the STATUS_ MFR_SPEFIFIC bit 1 will assert If the ShortCycle event occurs and the ShortCycle MFR_CHAN_CONFIG bit is not set the PWM chann...

Страница 81: ...te of the RUNn pin instructs the device to change to another mode If the part is stored in the MARGIN_LOW HIGH state the next RESET or POWER_ON cycle will ramp to that state If the OPERATION command i...

Страница 82: ...rent sense information digitized by Channel 1 s current sense input ISNS1a ISNS1a 1 Temperature sensed via TSNS0a is used to temperature correct the current sense information digitized by Channel 1 s...

Страница 83: ...nuous con duction mode Whenever the channel is ramping on the PWM mode will be discontinuous regardless of the value of this bit This command has one data byte MFR_PWM_COMP The MFR_PWM_COMP command se...

Страница 84: ...els must be commanded off If either channel is in the RUN state and this command is written the command will be NACK d and a BUSY fault will be asserted BIT MEANING 7 Reserved 6 5 00b 01b 10b 11b Inpu...

Страница 85: ...command has two data bytes and is formatted in Linear_5s_11s format VOLTAGE Input Voltage and Limits COMMAND NAME CMD CODE DESCRIPTION TYPE PAGED DATA FORMAT UNITS NVM DEFAULT VALUE VIN_OV_FAULT_LIMI...

Страница 86: ...ment in milliohms See also READ_VIN Set MFR_RVIN equal to 0 if no filter element is used This command has two data bytes and is formatted in Linear_5s_11s format Output Voltage and Limits COMMAND NAME...

Страница 87: ...rt indicates if it is busy making a calculation Monitor bits 5 and 6 of MFR_COMMON Either bit is low if the part is busy If this wait time is not honored and the VOUT_COMMAND is modified above the old...

Страница 88: ...The VOUT_MARGIN_LOW command loads the unit with the voltage to which the output is to be changed in volts when the OPERATION command is set to Margin Low The value must be less than VOUT_COMMAND This...

Страница 89: ...m R Word Y L11 m Factory Only NVM Set at Factory MFR_IOUT_CAL_GAIN_TC 0xF6 Temperature coefficient of the current sensing element R W Word Y CF Y 3800 0x0ED8 IOUT_OC_FAULT_LIMIT 0x46 Output overcurren...

Страница 90: ...85 32 26 18 86 61 55 10 48 34 28 20 42 66 60 11 34 37 31 21 14 68 62 11 74 38 32 22 27 72 66 12 37 40 34 23 41 76 70 13 01 42 36 24 55 79 73 13 64 44 38 Note This is the peak of the current waveform...

Страница 91: ...sense element in m R W Word L11 m Y 1 0 0xBA00 MFR_IIN_CAL_GAIN The MFR_IIN_CAL_GAIN command is used to set the resistance value of the input current sense resistor in milliohms see also READ_IIN This...

Страница 92: ...the remote sensing of the temperature in the inductor This command has two data bytes and is formatted in Linear_5s_11s format The part starts the calibration with a 273 15 so the default adjustment i...

Страница 93: ...s the VOUT commanded value R W Word Y L11 ms Y 3 0 0xC300 TON_MAX_FAULT_LIMIT 0x62 Maximum time from the start of TON_RISE for VOUT to cross the VOUT_UV_FAULT_LIMIT R W Word Y L11 ms Y 5 0 0xCA80 VOUT...

Страница 94: ...time after TOFF_FALL completed for the unit to decay below 12 5 R W Word Y L11 ms Y 0 0x8000 TOFF_DELAY The TOFF_DELAY command sets the time in milliseconds from when a stop condition is received unt...

Страница 95: ...o TOFF_DELAY TOFF_ FALL 136ms Valid values are from 136ms to 65 52 seconds in 16ms increments To assure a minimum off time set the MFR_RESTART_DELAY 16ms longer than the desired time The output rail c...

Страница 96: ...ON TYPE PAGED DATA FORMAT UNITS NVM DEFAULT VALUE VOUT_OV_FAULT_RESPONSE 0x41 Action to be taken by the device when an output overvoltage fault is detected R W Byte Y Reg Y 0xB8 VOUT_UV_FAULT_RESPONSE...

Страница 97: ...rn off and then to turn back on or Bias power is removed and reapplied to the LTM4680 00 Part performs OV pull down only or OV_PULLDOWN i e turns off the top MOSFET and turns on lower MOSFET while VOU...

Страница 98: ...receives a RESTORE_USER_ALL command The device receives a MFR_RESET command The device supply power is cycled 00 The PMBus device continues operation without interruption Ignores the fault functionall...

Страница 99: ...IMIT has been exceeded This command has one data byte Fault Responses Output Current COMMAND NAME CMD CODE DESCRIPTION TYPE PAGED DATA FORMAT UNITS NVM DEFAULT VALUE IOUT_OC_FAULT_RESPONSE 0x47 Action...

Страница 100: ...5 3 11 The LTM4680 shuts down immediately and responds as programmed by the Retry Setting in bits 5 3 5 3 Retry Setting 000 The unit does not attempt to restart The output remains disabled until the f...

Страница 101: ...Not supported Writing this value will generate CML fault 2 0 Delay Time XXX Not supported Value ignored Fault Responses External Temperature COMMAND NAME CMD CODE DESCRIPTION TYPE PAGED DATA FORMAT U...

Страница 102: ...fault 10 The device shuts down immediately disables the output and responds according to the retry setting in bits 5 3 11 Not supported Writing this value will generate a CML fault 5 3 Retry Setting 0...

Страница 103: ...Reserved b 8 Mfr_fault0_propagate_ut Mfr_fault1_propagate_ut 0 No action if the UT_FAULT_LIMIT fault is asserted 1 Associated output will be asserted low if the UT_FAULT_LIMIT fault is asserted FAULT0...

Страница 104: ...0x00 FAULT_IGNORE The LTM4680 continues operation without interruption The device also Sets the MFR Bit in the STATUS_WORD Sets Bit 0 in the STATUS_MFR_SPECIFIC Command to Indicate FAULTn Is Being Pul...

Страница 105: ...ASC ADI MFR_MODEL 0x9A Manufacturer part number in ASCII R String N ASC LTM4680 MFR_SPECIAL_ID 0xE7 Manufacturer code representing the LTM4680 R Word N Reg 0x414X PMBus_REVISION The PMBUS_REVISION co...

Страница 106: ...used to clear any fault bits that have been set This command clears all bits in all status commands simultaneously At the same time the device negates clears releases its ALERT pin signal output if th...

Страница 107: ...None STATUS_IOUT 0x00 None STATUS_TEMPERATURE 0x00 None STATUS_CML 0x00 None STATUS_INPUT 0x00 None STATUS_MFR_SPECIFIC 0x11 Bit 4 internal PLL unlocked bit 0 FAULT pulled low by external device PMBu...

Страница 108: ...et They may be cleared by writing a 1 to their bit position in the STATUS_BYTE in lieu of a CLEAR_ FAULTS command This command has one data byte STATUS_WORD The STATUS_WORD command returns a two byte...

Страница 109: ...by means other than using the CLEAR_FAULTS command Any supported fault bit in this command will initiate an ALERT event This command has one data byte STATUS_IOUT The STATUS_IOUT command returns one b...

Страница 110: ...ULTS command Any supported fault bit in this command will initiate an ALERT event Bit 3 of this command is not latched and will not generate an ALERT even if it is set This command has one data byte S...

Страница 111: ...LTS command Any supported fault bit in this command will initiate an ALERT event This command has one data byte STATUS_MFR_SPECIFIC The STATUS_MFR_SPECIFIC commands returns one byte with the manufactu...

Страница 112: ...LTM4680 configured to drive SYNC pin 9 Channel 1 Power Good 8 Channel 0 Power Good 7 LTM4680 Driving RUN1 Low 6 LTM4680 Driving RUN0 Low 5 RUN1 Pin State 4 RUN0 Pin State 3 LTM4680 Driving FAULT1 Low...

Страница 113: ...PEAKS R Word Y L11 A NA MFR_VOUT_PEAK 0xDD Maximum measured value of READ_VOUT since last MFR_CLEAR_PEAKS R Word Y L16 V NA MFR_VIN_PEAK 0xDE Maximum measured value of READ_VIN since last MFR_CLEAR_PE...

Страница 114: ...s read only command has two data bytes and is formatted in Linear_5s_11s format READ_TEMPERATURE_2 The READ_TEMPERATURE_2 command returns the LTM4680 s die temperature in degrees Celsius of the intern...

Страница 115: ...bytes and is formatted in Linear_16u format MFR_VIN_PEAK The MFR_VIN_PEAK command reports the highest voltage in volts reported by the READ_VIN measurement This command is cleared using the MFR_CLEAR...

Страница 116: ...is set to any value except standard round robin telemetry 0 all warnings and faults associated with telemetry other than the selected parameter are effectively disabled and voltage servoing is disable...

Страница 117: ...E_UNLOCK to 0x2B followed by 0xC4 The LTM4680 will now communicate normally and the project file can be updated To write the updated project file to the NVM issue a STORE_USER_ALL command When VIN is...

Страница 118: ...re listed in Table 21 If the user accesses the MFR_FAULT_LOG command and no fault log is present the command will return a data length of 0 If a fault log is present the MFR_FAULT_LOG will return a bl...

Страница 119: ...Fault Source 7 0 Reg 4 Refer to Table 17 MFR_REAL_TIME 7 0 Reg 5 48 bit share clock counter value when fault occurred 200 s resolution 15 8 6 23 16 7 31 24 8 39 32 9 47 40 10 MFR_VOUT_PEAK PAGE 0 15 8...

Страница 120: ...he header and all 6 event pages to EEPROM READ_VOUT PAGE 0 15 8 LIN 16 27 7 0 LIN 16 28 READ_VOUT PAGE 1 15 8 LIN 16 29 7 0 LIN 16 30 READ_IOUT PAGE 0 15 8 LIN 11 31 7 0 LIN 11 32 READ_IOUT PAGE 1 15...

Страница 121: ...5 8 WORD 61 7 0 WORD 62 STATUS_WORD PAGE 1 15 8 WORD 63 7 0 WORD 64 STATUS_MFR_SPECIFIC PAGE 0 BYTE 65 STATUS_MFR_SPECIFIC PAGE 1 BYTE 66 EVENT n 5 Oldest Recorded Data READ_VOUT PAGE 0 15 8 LIN 16 12...

Страница 122: ...an take up to 8ms to clear This write only command is send bytes Block Memory Write Read COMMAND NAME CMD CODE DESCRIPTION TYPE PAGED DATA FORMAT UNITS NVM DEFAULT VALUE MFR_EE_UNLOCK 0xBD Unlock user...

Страница 123: ...FSWPH_CFG F9 SGND A10 VOUT1 B10 VOUT1 C10 COMP1b D10 COMP1a E10 VTRIM1_CFG F10 SGND A11 VOSNS1 B11 VOUT1 C11 WP D11 SHARE_CLK E11 VOUT0_CFG F11 RUN1 A12 VOSNS1 B12 VOUT1 C12 VTRIM0_CFG D12 VDD25 E12 V...

Страница 124: ...GNATION PER JESD MS 028 AND JEP95 4 3 DETAILS OF PIN 1 IDENTIFIER ARE OPTIONAL BUT MUST BE LOCATED WITHIN THE ZONE INDICATED THE PIN 1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE PACKAGE TOP VIE...

Страница 125: ...igital Inputs specification Added FAULTn to Digital Inputs specification Changed FREQUENCY_SWITCH from 575kHz to 350kHz Changed A11 from VOSN0 to VOSN1 Changed bit 3 2 to bit 6 5 on INPUT CURRENT SENS...

Страница 126: ...ns and fault logging RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTM4675 Dual 9A or Single 18A Module Regulator 4 5V VIN 17V 0 5V VOUT 5 5V 16mm 11 9mm 3 51mm BGA LTM4686 Ultrathin Dual 10A or Sing...

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Содержание ANALOG DEVICES LTM4680

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