ADP1147 Analog Devices, ADP1147 Datasheet
ADP1147
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ADP1147 Summary of contents
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... Modems Portable Instruments GPS Systems GENERAL DESCRIPTION The ADP1147 is part of a family of step-down switching regula- tors featuring automatic sleep mode to maintain high efficiency at low output currents. These regulators drive an external P-chan- nel MOSFET at frequencies up to 250 kHz using constant off- time current mode architecture. ...
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... Extended Commercial Temperature Range . . – +85 C Junction Temperature +150 C Storage Temperature Range . . . . . . . . . . . . – +150 C Lead Temperature (Soldering, 10 sec +300 calculated from the ambient temperature according to the following formulas: ADP1147AN-3.3, ADP1147AN- 110 C/W). ADP1147AR-3.3, ADP1147AR- +70 C, (Note ...
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... This provides the + input to the current comparator. The offset between Pins 4 and 5 together with R establish the current trip threshold. Shutdown When this pin is pulled high, it keeps the MOSFET turned off. When the pin is pulled to ground, theADP1147 functions normally. This pin cannot be left floating. GND ...
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... I – Amps OUT Figure 6. Typical Efficiency Losses 5.10 100mA 5.05 1 Amp 5.00 4.95 4.90 FIGURE 1 CIRCUIT 4.85 4.80 4. INPUT VOLTAGE – Volts Figure 9. ADP1147-5 Output Voltage vs. Input Voltage 1000 +5V SENSE OUT 800 600 V = +12V IN 400 V = +10V IN 200 100 200 300 FREQUENCY – ...
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... P-DRIVE IN 390pF GND 3300pF SHUTDOWN SENSE(–) SENSE(+) 1000pF Figure 17. –5– ADP1147 100nC 50nC 110 140 170 200 230 OPERATING FREQUENCY – kHz Figure 14. Gate Charge Supply ...
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... ADP1147 APPLICATIONS Description OF ADP1147 Operation* (See Functional Diagram) The ADP1147 uses a current mode, constant off time structure to switch an external P-channel MOSFET. The operating fre- quency of the device is determined by the value of the external capacitor connected to the C pin. T The output voltage is sensed by an internal voltage divider which is connected to the Sense(– ...
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... V > standard threshold MOSFET ( used peak-to-peak SENSE threshold MOSFET (V When a logic level MOSFET is used, the ADP1147 supply volt- age must be less than the absolute maximum V OFF or MOSFET (e.g., < IRF7304). The maximum output current requirement for power MOSFET. When the ADP1147 is oper- ...
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... Schottky diode: 1. The dc supply current is the current which flows into V Pin 1, less the gate charge current. For V ADP1147 dc supply current is 160 A for no load, and in- creases proportionally with load constant 1.6 mA af- ter the ADP1147 has entered continuous mode. Because the dc bias current is drawn from V creases with input voltage ...
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... Schottky diode duty cycle multiplied by the load current. Figure 6 shows how the efficiency losses add typical ADP1147 regulator. The gate charge loss is responsible for the majority of the efficiency lost in the midcurrent region. If Power Saving Mode operation was not employed at low cur- rents, the gate charge loss alone would cause the efficiency to drop to unacceptable levels ...
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... SENSE 3. Are the Sense (–) and Sense (+) leads routed together with minimum PC trace spacing? The 1000 pF capacitor between Pins 4 and 5 should be as close as possible to the ADP1147. 4. Does the (+) plate of C P-channel MOSFET as closely as possible? This capacitor provides the ac current to the P-channel MOSFET. ...
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... BSC 8-Lead Plastic SOIC (SO-8) 0.1968 (5.00) 0.1890 (4.80 0.1574 (4.00) 0.2440 (6.20 0.1497 (3.80) 0.2284 (5.80) PIN 1 0.0688 (1.75) 0.0098 (0.25) 0.0532 (1.35) 0.0040 (0.10) 8 0.0500 0.0192 (0.49) 0 SEATING 0.0098 (0.25) (1.27) 0.0138 (0.35) PLANE BSC 0.0075 (0.19) –11– ADP1147 0.195 (4.95) 0.115 (2.93) 0.015 (0.381) 0.008 (0.204) 0.0196 (0.50 0.0099 (0.25) 0.0500 (1.27) 0.0160 (0.41) ...
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