Test Procedure for the NCV47821 Evaluation Board The NCV47821 is dual channel adjustable Low Dropout Regulator with: - Two adjustable output voltages from 3.3 V to 20 V - Two adjustable current limits up to 300 mA - Enable inputs with 3.3 V Logic compatible thresholds - Diagnostic Features: Short To Battery (STB) and Open Load (OL) in OFF State Internal Components for OFF State Diagnostics Open Collector Flag Output For detailed information read the technical specification. Power supplying of the chip is possible from one or two independent sources. INPUT1 must be always supplied and INPUT2 as optional for Vin2 supply. Basic procedure of function verification, Diagnostic Functions inactive 1. Power supplying a. Power supplying from one source Connect the test setup as is shown in Figure 1 (See Table 1 with required equipment). Connect power supply to INPUT1 connector J1 (Power supplying of INPUT2 is not needed). - Hi_F – Positive Force line - Hi_S – Positive Sense line - Lo_F – Negative Force line - Lo_S – Negative Sense line Connect Vin2 pin to INPUT1 via appropriate position of jumper “Vin2 to IN1 or IN2 connection”. b. Power supplying from two sources Connect the test setup as is shown in Figure 1 (See Table 1 with required equipment). Connect two power supplies to INPUT1 connector J1 and to INPUT2 connector J2, respectively. - Hi_F – Positive Force line - Hi_S – Positive Sense line - Lo_F – Negative Force line - Lo_S – Negative Sense line Values of input voltages Vin1 and Vin2 can be different. This option is suitable for reducing of power dissipation on chip. Connect Vin2 pin to INPUT2 via appropriate position of jumper “Vin2 to IN1 or IN2 connection”. 2. Current Limit settings Connect jumpers J10 – J13 for output current limitation from Vout1 pin and J20 – J23 for output current limitation from Vout2 pin. - Jn0 – ILIMn0 ~ 17 mA - Jn1 – ILIMn1 ~ 170 mA - Jn2 – ILIMn2 ~ 280 mA - Jn3 – ILIMn3 – RCSOn3 positions available for individual current limit setting by resistor from range 850 Ω to 25.5 kΩ 3. Diagnostic Function (inactive) Connect DE and CS inputs to GND via appropriate jumper to disable diagnostic function. 03/25/2016 1 www.onsemi.com 4. Power ON Set Input Voltage and turn on Power Supply/Supplies. Enable output of the channel to power the regulated output voltage by connecting the ENABLE input to corresponding Vin via jumper. Enabling can be performed by external voltage source as well. 5. Load the outputs by resistive loads connected via jumpers: (Iout ~ 225 mA) - J5, J7 – 22 Ω (Iout ~ 15 mA) - J6, J8 – 330 Ω External loads can be used instead build-in resistive loads as well. 6. Monitor Output Voltages, given according to Equation 1. _ 7. 1.275 1 (eq. 1) Monitor Current Sense Output voltages on appropriate connector. They should be max 2.55 V in steady state. The CSO voltages are proportional to output currents according to Equation 2. _ 8. _ _ _ (eq. 2) Compare your results with measured results in Table 2. Table 2: Measured Results Value Parameter Test Conditions Symbol Vin = 13.5 V, Vout_nom_n = 5.02 V, I out_n = 5 mA, RCSO_n = Short to ground Output Voltage Vin = 13.5 V, Vout_nom_n = 5.02 V, I out_n = 200 mA, RCSO_n = Short to ground Vin = 13.5 V, Vout_nom_n = 5.02 V, Vout_n = 90 % of Vout_nom_n, RCSO_n = 15 kΩ Output Current Vin = 13.5 V, Vout_nom_n = 5.02 V, Vout_n = 90 % of Vout_nom_n, RCSO_n = 1.5 kΩ Vin = 13.5 V, Vout_nom_n = 5.02 V, Vout_n = 90 % of Vout_nom_n, RCSO_n = 910 Ω Vin = 13.5 V, Vout_nom_n = 5.02 V, Vout_n = 0 V, RCSO_n = 15 kΩ Output Current Vin = 13.5 V, Vout_nom_n = 5.02 V, Vout_n = 0 V, RCSO_n = 1.5 kΩ Vin = 13.5 V, Vout_nom_n = 5.02 V, Vout_n = 0 V, RCSO_n = 910 Ω 9. Nominal Vout1 Vout2 Vout1 Measured 5.02 4.98 4.99 Vout2 4.99 Iout1 16.7 16.8 169 170 281 281 17.3 17.4 174 174 289 290 Iout2 Iout1 Iout2 Iout1 Iout2 Iout1 Iout2 Iout1 Iout2 Iout1 Iout2 Unit 4.98 17 170 280 17 170 280 V mA mA Power OFF Disable output of the channel by connecting the ENABLE input to GND via jumper. Or Turn OFF external voltage source. 03/25/2016 2 www.onsemi.com Diagnostic Functions verification 1. Diagnostic Function (active) Perform steps from 1 to 4 of Basic procedure of function verification and keep both channels disabled. Short to battery detection (in OFF State) Set DE input to 5 V via appropriate jumper. Set CS input to GND. If EF is LOW, Short to Battery on CH1 event occurred. Set CS input to 5 V. If EF is LOW, Short to Battery on CH2 event occurred. Open Load detection (in OFF State) Set DE input to 5 V via appropriate jumper. Enable detection by connecting the ENABLE input to corresponding Vin via jumper. Enabling can be performed by external voltage source as well. Set CS input to GND. If EF is LOW, Open Load on CH1 event occurred. Set CS input to 5 V. If EF is LOW, Open Load on CH2 event occurred. Combine selection RCSO1,2 and Resistive Loads. You can use external load as well. Overcurrent detection Set DE input to GND via appropriate jumper. Enable output of the channel to power the regulated output voltage by connecting the ENABLE input to corresponding Vin via jumper. Enabling can be performed by external voltage source as well. Set CS input to GND. If EF is LOW, Overcurrent on CH1 occurred and CSO1 output is HIGH. Set CS input to 5 V. If EF is LOW, Overcurrent on CH2 occurred and CSO2 output is HIGH. Combine selection RCSO1,2 and Resistive Loads. You can use external load as well. For supplying DE and CS inputs is used an 5 V LDO regulator U2 powered from INPUT1. 03/25/2016 3 www.onsemi.com Figure 1. General Test Setup Table 1: Required Equipment Equipment Power Supply Load V - meter A - meter 03/25/2016 Ranges 0 V – 45 V / 2 A 0 mA – 1 A 0 V – 45 V 0 mA – 1 A 4 www.onsemi.com Figure 2. Top side PCB Layout (3 x 3 inch) 03/25/2016 5 www.onsemi.com