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2-5

Using the THS4131 EVM

2.5

Power Down Verification

This EVM is used to evaluate devices with and without the shutdown function.
Therefore, this step is only applicable if the device has a shutdown function.
Please see the data sheet for power-down verification.

1) Insert the jumper JU1 to power down the device. The current consumption

(dc current meters) should drop to less than 1.5 mA. Remember to dis-
count the current flow through the 10-k

 pullup resistor on the EVM when

calculating the device current consumption in the shutdown mode.

2) Turn off the power supply and disconnect the wiring.

3) Turn off the function generator and disconnect the wiring.

4) Basic operation of the operational amplifier and its EVM is complete.

2.6

Measuring the Frequency Response

This EVM is designed to easily interface with network analyzers. Jumpers J3
and J4 facilitate the use and insertion of the differential probes at the input and
output nodes. It is important to consider the following steps to ensure optimal
performance in terms of bandwidth, phase margin, gain,  and peaking

1) Connect the power supply according to the power supply set up (section

2.2)

2) Use proper load values. Loads directly effect the performance of the

differential operational amplifier (the suggested value is 200 

differentially, 100 

 on each output node).

Caution:

Incorrect connections cause excessive current flow and may damage
the device.

3) Place the GND connection of the probe as close as possible to the output

nodes. Use the GND holes on the EVM. The GND holes create a shorter
route to the GND plane and output nodes.

4) Place the probe at the input nodes, set the power level of the network

analyzer to the proper level (information in the data sheet typically is
produced at –20 dBm power level), and calibrate the network analyzer.

Note:

If a differential probe is used, verify that resistors R1a, R1b, R4b, and R4a
are in place. The resistors are 0 

 values providing the path to the differential

probe terminals.

5) Place the probe at the output nodes (if a differential probe is used, insert

the probe into the provided jumper), and measure the frequency
response.

Summary of Contents for THS4131

Page 1: ...THS4131 EVM User s Guide for High Speed Fully Differential Amplifier February 2001 Mixed Signal Products User s Guide SLOU110...

Page 2: ...esign TI does not warrant or represent that any license either express or implied is granted under any patent right copyright mask work right or other intellectual property right of TI covering or rel...

Page 3: ...It is recommend that the user initially review the datasheet of the device under test It is also helpful to review the schematic and layout of the THS4131 EVM to determine the design techniques used i...

Page 4: ...HS4131 data sheet literature number SLOS318 THS4131 application report literature number SLOA054A Fully Differential Amplifiers FCC Warning This equipment is intended for use in a laboratory test envi...

Page 5: ...Configuration 1 3 1 5 THS4131 EVM Schematic 1 4 1 6 Additional Sample Schematics 1 5 1 7 THS4131 EVM Layout 1 7 2 Using the THS4131 EVM 2 1 2 1 Required Equipment 2 2 2 2 Power Supply Setup 2 2 2 3 I...

Page 6: ...ansformer 1 5 1 5 VICR Level Shifter 1 6 1 6 Butterworth Filter With Multiple Feedback 1 6 1 7 Top Layer Silkscreen 1 7 1 8 Top Layer 1 Signals 1 7 1 9 Internal Plane Layer 2 Ground Plane 1 8 1 10 Int...

Page 7: ...of the EVM In addition the schematic of the default circuit has been added to depict the components mounted on the EVM when it is received by the customer This configuration correlates to the single...

Page 8: ...h a 50 resistor to provide correct line impedance matching 1 2 Evaluation Module Features THS4131 high speed operational amplifier EVM features include J Voltage supply operation range 5 V to 15 V ope...

Page 9: ...see the THS4131 data sheet TI literature number SLOS318 1 4 Schematic of the Populated Circuit Default Configuration For verification of jumper locations and other bypass components see the complete...

Page 10: ...THS4131 EVM Schematic 1 4 Introduction and Description 1 5 THS4131 EVM Schematic Figure 1 2 Schematic...

Page 11: ...mination Resistor R3a R6b Note Fully differential in fully differential out signal path See the Texas Instruments February 2001 Analog Applications Journal for the information on the termination resis...

Page 12: ...C RPU1 RPU2 VCC Note Shiftingthe VICR within the specified range in the data sheet via RPU1 and RPU2 if the VICR is out of the specified range See the Application section of the data sheet for the THS...

Page 13: ...31 EVM Layout 1 7 Introduction and Description 1 7 THS4131 EVM Layout Figure 1 7 Top Layer Silkscreen TEXAS INSTRUMENTS THS4131 EVM REV_B Figure 1 8 Top Layer 1 Signals TEXAS INSTRUMENTS THS4131 EVM R...

Page 14: ...THS4131 EVM Layout 1 8 Introduction and Description Figure 1 9 Internal Plane Layer 2 Ground Plane Figure 1 10 Internal Plane Layer 3 VCC Plane...

Page 15: ...THS4131 EVM Layout 1 9 Introduction and Description Figure 1 11 Bottom Layer 4 Ground and Signal...

Page 16: ...1 10 Introduction and Description...

Page 17: ...terminals on the EVM and their function In addition it suggests the components and equipment needed to operate the EVM Topic Page 2 1 Required Equipment 2 2 2 2 Power Supply Setup 2 2 2 3 Input and O...

Page 18: ...dc power supply to 5 V 2 Make sure the dc power supply is turned off before proceeding to the next step 3 Connect the positive terminal of the power supply to the positive terminal of the current mete...

Page 19: ...erator to J1 VI on the EVM 5 Using a BNC to SMA cable connect the oscilloscope to J3 VO on the EVM 6 Using a BNC to SMA cable connect the oscilloscope to J4 VO on the EVM Set the oscilloscope to 0 5 V...

Page 20: ...rn on the function generator 4 Verify the oscilloscope is showing two 1 MHz sine waves with amplitude of 0 125 V The dc offset of the signal must be below 50 mV Note VOUT and VOUT should be 180 degree...

Page 21: ...sider the following steps to ensure optimal performance in terms of bandwidth phase margin gain and peaking 1 Connect the power supply according to the power supply set up section 2 2 2 Use proper loa...

Page 22: ...center point of the power supply For example if 5 sources are used the VOCM level will be set to zero 2 7 Butterworth Filter An example of a Butterworth filter implemented with multiple feedback arch...

Page 23: ...r C1 C4 C5 C6 Capacitor 0 1 F ceramic 0805 4 Murata GRM40 X7R104K25 C7 C8 Capacitor 6 8 F 35 V 20 tantalum SM 7343 2 Sprague 293D685X9035D2T C1A C1B C2 C3A C3B Open 0805 5 J1 J2 J3 J4 SMT_PCB_MT SMA j...

Page 24: ...sistor 402 1 0805 2 Digi Key P402CTR ND R11 Resistor 10 k 1 0805 1 Digi Key P10 KCTR ND R10 RX3 RX6 Resistor 49 9 1 1206 3 Digi Key P49 9FTR ND R16 R7 Open 1206 2 R36aA R36aB R36bA R36bB High precisio...

Page 25: ...nce This improves high frequency bypassing and reduces harmonic distortion A proper ground plane on both sides of the PCB should be used with high speed circuit design This provides low inductive grou...

Page 26: ...g a transmission line with its characteristic impedance the amplifier s load then appears to be purely resistive and reflections are absorbed at each end of the line Another advantage of using an outp...

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