USERS MANUAL ISL8200AMEV1PHZ AN1738 Rev 0.00 Evaluation Board May 10, 2012 ISL8200AMEV1PHZ Evaluation Board V = 3V TO 20V IN PGOOD V REMOTE SENSING OUT POINTS MODULE GROUP V OUT LOAD UP TO 10A DIMENSIONS: 2.5 X 4.5 INCHES V MONITORING POINTS OUT FIGURE 1. ISL8200AMEV1PHZ EVALUATION BOARD The ISL8200AM is a complete 10A step-down current 7. Set the electronic load to a desired load current. share-able switch mode power module in a low profile 8. Enable the power supply first and then the load the LED for package. It can be used in standalone single-phase operation PGOOD will be red when the module is not regulating. as well as current shared applications where multiple modules 9. Push the toggle on SW1 to the right the PGOOD LED should are connected in parallel. now be green to indicate proper operation. The ISL8200AMEV1PHZ evaluation board is used to demonstrate performance of the ISL8200AM in a single phase Shutdown setup. The input voltage is from 3V to 20V, and the output can 1. Disable the device by pushing the toggle on SW1 to the left. support a 10A maximum load with a voltage range from 0.6V up to 6V with the proper output capacitor rating. 2. Turn off the electronic load. 3. Turn off the power supply. Recommended Equipment 0V to 20V power supply with at least 15A source current Circuits Description capability. PVIN and GND banana plugs are the input power terminals. One Electronic Load capable of sinking current up to 10A. Two input electrolytic capacitor footprints are provided to Digital multi-meters (DMMs). handle the input current ripple. Two Sanyo Poscaps (2TPF330M6, 330F, ESR 6m ) are used Quick Start as output E-caps. These poscaps are rated for output voltages up to 2V, so they should be removed if a higher VOUT is 1. Connect the PVIN and GND banana jacks to a power supply required. The footprints of the Sanyo capacitors can and connect a load to the VOUT and GND lugs. accommodate T530 (ultra-low ESR) tantalum capacitors for 2. A multimeter can be hooked to TP310 (+) and TP34 (-) to higher voltages. monitor VOUT. VOUT and GND are output lugs for load connections. 3. Open the jumpers marked PVIN and VCC. VSEN+ and VSEN- are output voltage sensing points. These 4. Short the jumpers marked 1.2V and FIXED. This sets the pins can be used to monitor and evaluate the system voltage output voltage to 1.2V and sets the OCP trip point to its regulations. If the user wants to use these test posts for open condition. remote sensing, RM+2, RM-2 need to be changed to higher 5. Push the toggle on SW1 to the left (with respect to the values, such as 10. board above). To assess stability, RM+2 can be changed to a 100 resistor, 6. Set the input supply to 12V. then inject the signal across VSEN+ and VSEN PRIME. AN1738 Rev 0.00 Page 1 of 6 May 10, 2012ISL8200AMEV1PHZ JP201 is a SIP connector that can be used with R223 = 0 For example, in a 5V application where it is desired to have the installed to inject a clock signal to synchronize the module to. part turn off at 4V and recover at 4.5V, the V that goes in HYS The default phase shift of the CLKOUT signal from the module Equation 3 is 0.5V. causes a second module to switch with a phase shift of 180. This can be demonstrated on the 2-phase evaluation board, (EQ. 2) UVLO = V + V TURN ON HYS FTH ISL8200AMEVAL2PHZ. R203 and C210 are small added filters for the VIN pins. I = N x 30A V HYS The Overcurrent Protection (OCP) limit can be controlled by HYS (EQ. 3) R1 = ------------- I shorting the jumper marked FIXED and populating a resistor in N = number HYS R209As location, as per your desired OCP trip point. As another option, by shorting the jumper marked ADJ1, you can tune the R V 1 ENREF (EQ. 4) --------------------------------------- OCP level using the potentiometer labeled R241. To measure the R2 = V = 0.8V ENREF V V FTH ENREF resistance of R241, simply turn off the part and remove the short across ADJ1 and place a resistance meter across its terminals. For 12V applications, if it is desired to have the IC disabled when If the application is in the 3.3V range, tie VIN and PVCC to 5.0V. the input voltage drops below 9V and restart when V recovers IN However, in applications that involve a PVIN greater than 5.5V, above 10.6V, then R1 = 53.33k and R2 = 5.2k. open the jumper named PVIN, not doing so will increase the probability of tying VCC to a voltage greater than its capability. Efficiency Measurement Shorting the jumper marked VCC will allow you to use a separate power supply for VCC however this is not a necessity as VCC can The voltage and current meter can be used to measure input/output voltage and current. In order to obtain an accurate be internally generated within the module. measurement and prevent the voltage drop of PCB or wire trace, the voltage meter must be close to the input/output terminals. Evaluating Other Output For simplicity, the measuring point for the input voltage meter is Voltages at the PVIN TP terminal, and the measuring point for the output The ISL8200AMEV1PHZ kit has several preset outputs for voltage meter is at the TP310 terminal. convenience. 1.2V, 1.5V, 1.8V, 2.5V, 3.3V and 5.0V can be easily The efficiency equation is shown in Equation 5: selected by shorting their appropriate jumper. There is also a P V I Output Power OUT OUT OUT potentiometer provided that will allow for any other output ----------------------------------- ------------- ----------------------------------- (EQ. 5) Efficiency=== Input Power P V I voltage between 0.6V to 6V. Equation 1 governs the relationship IN IN IN between the VSET resistors (R221A thru R221F) and the output voltage. Output Ripple/Noise V V where V = 0.6V OUT REF REF ------------------------------------- (EQ. 1) R221X = ROS Measurement V REF ROS = 2.2k internal Simple steps should be taken to ensure that there is minimum The output capacitors (C9 and C19) must be changed to support pickup noise due to high frequency events, which can be the corresponding output voltage. The onboard output capacitors magnified by the large ground loop formed by the oscilloscope- are rated at 2V max. probe ground. This means that even a few inches of ground wire on the oscilloscope probe may result in hundreds of millivolts of Programming the Input Voltage noise spikes when improperly routed or terminated. This effect can be overcome by using the short loop measurement method UVLO and its Hysteresis to minimize the measurement loop area for reducing the pickup By modifying the voltage divider at the EN pin connected to the noise. The short loop measurement method is shown in Figure 2. input rail (R1 and R2), the input UVLO and its hysteresis can be programmed. The ISL8200AMEV1PHZ evaluation board comes stocked with R1 = 8.25k and R2 = 3.01k this sets the UVLO level at 2.9V for a 3.3V application. For a 5V application, with a UVLO at 4V and recover at 4.5V, use R1 = 16.6k and R2 = 4.2k . The UVLO equations are re-stated OUTPUT CAP OOUTUTPPUTUT C CAP AP in the following, where R1 and R2 are the upper and lower OR OR MMOSFEOSFETT resistors of the voltage divider at the EN pin respectively, V is HYS the desired UVLO hysteresis and V is the desired UVLO falling FTH threshold a user selected value. Equation 2 describes V as HYS the point past the programmed UVLO level at which the device FIGURE 2. OUTPUT RIPPLE/NOISE MEASUREMENT turns on again. AN1738 Rev 0.00 Page 2 of 6 May 10, 2012