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Box Contents:
Two (2) Boards; one with varying impedance and one with ‘flat’ impedance

LM20143 Flat Impedance VRM Demo Board V1.0


Provisions are included for a Bode plot measurement, with the injection resistor, R5, included as well as test-points for the injection signal and measurement (TP3 and TP4). SMA output connectors are also included to simplify connections for many measurements including the 2-port output impedance measurement, step load and other common measurements.

The board is USB powered by connecting a USB cable with a type B connector to the power connector USB1. (CAUTION: R9 and R10 GET HOT - DO NOT TOUCH)

Test Points Function
TP1 Input voltage meter or probe
TP2 Ground for meter or probe
TP3 Bode injection
TP4 Bode injection
Model Description Price  
LM20143 LM20143 Flat Impedance VRM Demo Board V1.0

The circuit is an integrated point of load synchronous buck regulator with a 5V input and a 1.2V/2.5A output. The device uses emulated current mode control, making it simple to create a flat impedance output. Easily accessible 0805 chip size components make it easy to customize or experiment with different component values. This is a fully self-contained demo board using USB input power and an on-board resistive load.

Supported Measurements



2-port output impedance J2102A two SMA cables (optional two P2130A or J2130A)
Load Step J2111A or J2150A and J2130A or P2130A SMA cable
Ripple and Noise J2130A or P2130A SMA cable
Turn on overshoot Scope with probe or SMA cable
PSRR J2120A or J2111A and two voltage probes
Input Impedance J2120A voltage and current probe
Bode Plot J2100A or J2101A two voltage probes

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