OscilloscopeA digital or analog oscilloscope measures the output ripple. The oscilloscope must be set for
the following:
1-MΩ impedance
20-MHz bandwidth
AC coupling
1-µs / division horizontal resolution
20-mV / division vertical resolution
Test points TP7 and TP9 measure the output ripple voltage by placing
the oscilloscope probe tip through TP7 and holding the ground barrel on TP9
as shown in Figure 5-1. Using a leaded ground connection can induce additional noise due to the
large ground loop.
Voltage SourceThe input voltage source VIN must be a 0 to 14-V variable-DC source capable of supplying 10 ADC. Connect VIN to J1 as shown in Figure 5-2.
MultimetersV1: VIN at TP1 (VIN) and TP4 (GND). V2: VOUT at TP7 (VOUT) and TP9 (GND).
Output LoadThe output load must an electronic constant-resistance-mode load capable of 0 to 15 ADC at 1.2 V.
Figure 5-1 Tip and Barrel
Measurement for VOUT Ripple
Recommended Wire Gauge:
VIN to J1 (12-V input)
The recommended wire size is 1× AWG number 14 per
input connection, with the total length of wire less than four feet
(2 feet input, 2 feet return).
J3 to LOAD
The minimum recommended wire size is 2× AWG
number 14, with the total length of wire less than four feet (two
feet output, two feet return).