Richtek RT8239A Скачать руководство пользователя страница 6

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RT8239A/B/C

DS8239A/B/C-06 October 2012

www.richtek.com

Function Block Diagram

Pin No.

Pin Name

Pin Function

18 UGATE1

Upper Gate Driver Output for SMPS1. UGATE1 swings between PHASE1 and
BOOT1.

19 BOOT1

Boost Flying Capacitor Connection for SMPS1. Connect to an external
capacitor according to the typical application circuits.

BYP1

Switch Over Source Voltage Input for LDO5.

21 (Exposed Pad) GND

Analog Ground and Power Ground. The exposed pad must be soldered to a
large PCB and connected to GND for maximum power dissipation.

ENM (RT8239A)
SECFB (RT8239B/C)

SMPS2

PWM

Buck

Controller

BOOT2

UGATE2

PHASE2

LGATE2

GND

LDO5

FB2
ENTRIP2

PGOOD

SMPS1

PWM

Buck

Controller

BOOT1

UGATE1

PHASE1

LGATE1

LDO5

FB1

ENTRIP1

LDO5

REF

Switch Over Threshold

VIN

LDO5

On Time

TON

LDO3

BYP1

Power-On
Sequence

Clear Fault Latch

ENLDO

LDO5

10µA

LDO5

10µA

Содержание RT8239A

Страница 1: ...and assures fast load transient response while maintaining nearly constant switching frequency To eliminate noise in audio applications an ultrasonic mode is included which maintains the switching fre...

Страница 2: ...LGATE2 UGATE2 15 14 13 12 17 18 19 20 1 2 3 4 9 8 7 6 GND 21 11 5 16 10 LDO3 LDO5 ENTRIP2 TON FB1 ENTRIP1 ENLDO SECFB PGOOD BOOT2 PHASE2 BYP1 BOOT1 PHASE1 UGATE1 LGATE1 FB2 VIN LGATE2 UGATE2 15 14 13...

Страница 3: ...Application Circuit C8 3 3V RT8239A PHASE1 LGATE1 BOOT1 UGATE1 VIN 11 16 19 17 18 PHASE2 LGATE2 BOOT2 UGATE2 FB2 VIN 10 F 8 9 7 10 5 C6 R1 C2 0 1 F 5 5V to 25V 21 Exposed Pad GND N3 L2 C7 0 1 F R5 N4...

Страница 4: ...BOOT1 UGATE1 VIN 11 16 19 17 18 PHASE2 LGATE2 BOOT2 UGATE2 FB2 VIN 10 F 8 9 7 10 5 C6 R1 C2 0 1 F 5 5V to 25V 21 Exposed Pad GND N3 L2 C7 C8 3 3V 0 1 F R5 N4 R6 6 5k N1 L1 C4 C3 5V 0 1 F R2 N2 R3 15k...

Страница 5: ...typical application circuits 8 UGATE2 Upper Gate Driver Output for SMPS2 UGATE2 swings between PHASE2 and BOOT2 9 PHASE2 Switch Node for SMPS2 PHASE2 is the internal lower supply rail for the UGATE2 h...

Страница 6: ...t to an external capacitor according to the typical application circuits 20 BYP1 Switch Over Source Voltage Input for LDO5 21 Exposed Pad GND Analog Ground and Power Ground The exposed pad must be sol...

Страница 7: ...r Dissipation PD TA 25 C WQFN 20L 3x3 3 33W z Package Thermal Resistance Note 2 WQFN 20L 3x3 JA 30 C W WQFN 20L 3x3 JC 7 5 C W z Lead Temperature Soldering 10 sec 260 C z Junction Temperature 150 C z...

Страница 8: ...sis of 25 C 4700 ppm C Current Limit Adjustment Range VENTRIPx IENTRIPx x RENTRIPx 0 5 2 7 V Current Limit Threshold VENTRIPx GND PHASEx VENTRIPx 2V 180 200 225 mV Zero Current Threshold VZC GND PHASE...

Страница 9: ...tSSHx From ENTRIPx or ENM Enable 5 ms Thermal Shutdown Thermal Shutdown TSD 150 C Thermal Shutdown Hysteresis TSD 10 C Logic Input ENTRIPx Input Voltage VENTRIPx Clear Fault Level SMPSx Off Level 4 5...

Страница 10: ...operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied Exposure to absolute maximum rating conditions may aff...

Страница 11: ...IP1 5V VENTRIP2 1 5V ENLDO 5V DEM ASM VOUT2 Efficiency vs Load Current 0 10 20 30 40 50 60 70 80 90 100 0 001 0 01 0 1 1 10 Load Current A Efficiency VIN 8V RTON 100k VENTRIP1 5V VENTRIP2 1 5V ENLDO 5...

Страница 12: ...rrent 0 20 40 60 80 100 120 140 160 180 200 220 240 260 0 001 0 01 0 1 1 10 Load Current A Switching Frequency kHz 1 VIN 20V RTON 100k ENLDO VIN VENTRIP1 1 5V VENTRIP2 5V ASM DEM VOUT2 Switching Frequ...

Страница 13: ...V ASM DEM Standby Input Current vs Input Voltage 226 228 230 232 234 236 238 240 6 8 10 12 14 16 18 20 22 24 26 Input Voltage V Standby Input Current A 1 VENTRIP1 VENTRIP2 5V ENLDO VIN No Load LDO5 Ou...

Страница 14: ...5V ENLDO GND No Load Power Off from ENTRIP1 Time 4ms Div RT8239B C VIN 12V VENTRIP1 VENTRIP2 1 5V ENLDO VIN RTON 100k No Load VIN 12V VENTRIP1 VENTRIP2 1 5V ENLDO VIN RTON 100k No Load VOUT1 2V Div P...

Страница 15: ...nsient Response Time 20 s Div ENLDO VIN IOUT2 1A to 8A VOUT2_AC 50mV Div Inductor Current 5A Div UGATE2 20V Div LGATE2 5V Div VIN 12V RTON 100k Power Off from ENTRIP2 Time 20ms Div VIN 12V VENTRIP1 VE...

Страница 16: ...current limit threshold and the minimum off time one shot has timed out PWM Frequency and On time Control For each specific input voltage range the Mach ResponseTM control architecture runs with pseu...

Страница 17: ...aded controller automatically skips pulses In Ultrasonic Mode the low side switch gate driver signal is OR ed with an internal oscillator 25kHz Once the internal oscillator is triggered the as one or...

Страница 18: ...e inductor value and battery and output voltage GND sets the current limit threshold The resistor RILIM is connected to a current source from ENTRIPx which is 10 A typ at room temperature The current...

Страница 19: ...start SS automatically begins once the chip is enabled During soft start the internal current limit circuit gradually ramps up the inductor current from zero The maximum current limit value is set ex...

Страница 20: ...cycle VIN to reset the UVP fault latch and restart the controller Thermal Protection The RT8239A B C features thermal shutdown to prevent damage from excessive heat dissipation Thermal shutdown occurs...

Страница 21: ...nd output is enabled Both UGATEx and LGATEx are forced low and enter discharge mode LDO3 and LDO5 are active Exit by VIN POR or by toggling ENLDO ENTRIPx and ENM Discharge Either output is still high...

Страница 22: ...ansient response Output Capacitor Selection The capacitor value and ESR determine the amount of output voltage ripple and load transient response Thus the capacitor value must be greater than the larg...

Страница 23: ...ssible Keep current limit setting network as close as possible to the IC Routing of the network should avoid coupling to high voltage switching node Connections from the drivers to the respective gate...

Страница 24: ...accurate and reliable However no responsibility is assumed by Richtek or its subsidiaries for its use nor for any infringements of patents or other rights of third parties which may result from its u...

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