LM4128

EN

GND

Input

Enable

Output

R1

500 :

1 k:

I OUT

0.1 µF

LM4128

EN

GND

Input

Enable

+5V

100 k:

0.1 µF

V

V

REF_FORCE

REF_SENSE

LM4128

EN

GND

Input

Enable

V

REF

C

OUT

R

R

R/2

-V

REF

+5V

-5V

4.7 µF < C

LM4128, LM4128Q

www.ti.com

SNVS475E – NOVEMBER 2006 – REVISED APRIL 2013

PRINTED CIRCUIT BOARD and LAYOUT CONSIDERATIONS

References in SOT packages are generally less prone to PC board mounting than devices in Small Outline

(SOIC) packages. To minimize the mechanical stress due to PC board mounting that can cause the output

voltage to shift from its initial value, mount the reference on a low flex area of the PC board, such as near the

edge or a corner.

The part may be isolated mechanically by cutting a U shape slot on the PCB for mounting the device. This

approach also provides some thermal isolation from the rest of the circuit.

Bypass capacitors must be mounted close to the part. Mounting bypass capacitors close to the part will reduce

the parasitic trace components thereby improving performance.

Typical Application Circuits

Figure 18. Voltage Reference with Complimentary Output

Figure 19. Precision Voltage Reference with Force and Sense Output

Figure 20. Programmable Current Source

Copyright © 2006–2013, Texas Instruments Incorporated

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