PDF《Evaluation Board for the》

1 Component varies depending on the evaluation board model ordered. EVAL-ADP1752/ADP1753 Rev.

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12 OUTPUT VOLTAGE MEASUREMENT Figure

3 shows how the evaluation board can be connected to a voltage source and a voltmeter for basic output voltage accuracy measurements. A resistor can be used as the load for the regulator. Ensure that the resistor has a power rating adequate to handle the power expected to be dissipated across it. An electronic load can be used as an alternative. In addition, ensure that the voltage source can supply enough current for the expected load levels. Follow these steps to connect to a voltage source and voltmeter: 1. Connect the negative terminal (?) of the voltage source to one of the GND pads on the evaluation board. 2. Connect the positive terminal (+) of the voltage source to the VIN pad of the evaluation board. 3. Connect a load between the VOUT pad and one of the GND pads. 4. Connect the negative terminal (?) of the voltmeter to one of the GND pads. 5. Connect the positive terminal (+) of the voltmeter to the VOUT pad. The voltage source can now be turned on. If J1 is inserted (connecting EN to VIN for automatic startup), the regulator powers up. If the load current is large, connect the voltmeter as close as possible to the output capacitor to reduce the effects of IR drops. VOLTMETER + C VOLTAGE SOURCE 1.99711 LOAD + C 07739-003 Figure 3. Output Voltage Measurement Setup EVAL-ADP1752/ADP1753 Rev.

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12 LINE REGULATION For line regulation measurements, the regulator output is moni- tored while its input is varied. For good line regulation, the output must change as little as possible with varying input levels. To ensure that the device is not in dropout mode during this measurement, VIN must be varied between VOUTNOM + 0.4 V (or + 1.6 V, whichever is greater) and VINMAX. For example, for an ADP1752 with fixed 1.5 V output, VIN needs to be varied between 1.9 V and 3.6 V. This measurement can be repeated under different load conditions. Figure

4 shows the typical line regulation performance of an ADP1752 with fixed 1.5 V output. 1.520 1.515 1.510 1.505 1.500 1.495 1.490 1.485 1.480 C40 C5

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125 OUTPUT VOLTAGE (V) JUNCTION TEMPERATURE (°C) LOAD = 10mA LOAD = 100mA LOAD = 400mA LOAD = 800mA 07739-105 Figure 4. Output Voltage vs. Input Voltage LOAD REGULATION For load regulation measurements, the output of the regulator is monitored while the load is varied. For good load regulation, the output must change as little as possible with varying loads. The input voltage must be held constant during this measure- ment. The load current can be varied from

500 μA to

800 mA. Figure

5 shows the typical load regulation performance of an ADP1752 with fixed 1.5 V output for an input voltage of 1.9 V. 1.520 1.515 1.510 1.505 1.500 1.495 1.490 1.485 1.480

10 100 1k OUTPUT VOLTAGE (V) LOAD CURRENT (mA) 07739-106 Figure 5. Output Voltage vs. Load Current DROPOUT VOLTAGE Dropout voltage can be measured using the configuration shown in Figure 3. Dropout voltage is defined as the input-to- output voltage differential when the input voltage is set to the nominal output voltage. This applies onl........