The LTC2920 allows power supplies and power supply module output voltages to be precisely adjusted both up and down for automated PCB testing. The power supply output voltage is changed by sourcing or sinking current into the feedback node or voltage adjust pin of the power supply. This allows a system to test the correct operation of electrical components at the upper and/or lower power supply voltage limits specified for a given design (Power Supply "Margining").The LTC2920 uses a single resistor to set the voltage margining current. The margining current is adjustable over a 400:1 range. Precision margin currents can be supplied to within 0.6V of ground or VCC.The LTC2920-1 is a single margining controller. The LTC2920-2 has two independently controllable margining channels. Each channel has its own control pin and current setting resistor. The LTC2920-2 can be used to symmetrically margin two power supplies, or asymmetrically margin a single power supply.Both the LTC2920-1 and LTC2920-2 feature a trimmed onboard voltage reference. Typical power supply margining accuracy is better than 0.4%.ApplicationsAutomated PCB Production TestingAutomated Preventative Maintenance TestingDC/DC Converter Module Margining