Test Procedure for the CS51411 02/7/2005 Figure 1: Test Setup DC Power Supply 100 mA load (33 Ω resistor or electronic load) Table 1: Required Equipment Two Multimeters 1 A load (3.3 Ω resistor or electronic load) Oscilloscope CS51411 demo board *Note: Resistor loads heat up quickly at higher input voltages. Test Procedure: Equipment set up (see Figure 1): 1. Connect DC power supply to positive Vin (J2) and GND (J1). 2. Connect multimeter to measure Iin. 3. Connect another multimeter across J4 (+) and GND (J5) to measure Vout. Test procedure: 4. Set current limit low on power supply and slowly increase Vin to 6 V. 5. At this point the board should be switching. Check the switch node (J3) with the Oscilloscope. 6. Check 0 mA < IIN < 50 mA. 7. Increase Vin = 12 V. Vout should be around 3.8 V. 8. Connect a 100 mA load (33 Ω resistor) across J4 and J5. 9. Check Vout = 3.3 V. Check switch node (Figure 2). Frequency should be around 260 kHz. 10. Connect a 1 A load (3.3 Ω resistor) across J4 and J5. 11. Check Vout = 3.3 V. Check switch node (Figure 3). Frequency should be around 260 kHz. 12. Note Iin. 13. Short the output. Iin should be between 0 and Iin with 1 A load. 14. Increase Vin= 16 V. 15. Vout = 3.3 V. Note improved switch node duty cycle (Figure 4). Frequency should remain around 260 kHz. 16. Short the shut down pin, SHDNB (J7). Verify the board turns off (J3). Figure 2: Switch node, Vin = 12 V, 100 mA load Figure 3: Switch node, Vin = 12 V, 1 A load Figure 4: Switch node, Vin = 16 V, 1 A load