ADP199ACBZ-R7 datasheet(12/16 Pages) AD

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ADP199

Data Sheet

Rev. 0 | Page 12 of 16

APPLICATIONS INFORMATION

GROUND CURRENT

The major source for ground current in the ADP199 is the internal

charge pump for the FET drive circuitry. Figure 30 shows the

typical ground current when VEN = VIN, and varies from 1.1 V

to 3.6 V.

0.8

1.2

1.6

2.0

2.4

2.8

3.2

3.6

VIN (V)

5mA

10mA

50mA

100mA

200mA

500mA

Figure 30. Ground Current vs. Input Voltage, Different Load Current

ENABLE FEATURE

The ADP199 uses the EN input to enable and disable the VOUT

output. As shown in Figure 31, when a rising voltage (VEN) on

the EN pin crosses the active threshold, VOUT turns on. When

a falling voltage (VEN) on the EN pin crosses the inactive

threshold, VOUT turns off.

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1.21.3

1.41.51.61.7

1.81.92.02.1

ENABLE VOLTAGE (V)

VOUT AT 3.3V

Figure 31. Typical EN Operation, VIN = 3.3 V

ENABLE VOLTAGE (V)

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

VOUT AT 1.2V

Figure 32. Typical EN Operation, VIN = 1.2 V

As shown in Figure 31, the EN pin has hysteresis built into it.

This prevents on/off oscillations that can occur due to noise on

the EN pin as it passes through the threshold points.

The EN pin active/inactive thresholds derive from the VIN voltage;

therefore, these thresholds vary with the changing input voltage.

Figure 33 shows the typical EN active/inactive thresholds when

the input voltage varies from 1.1 V to 3.6 V.

0.5

1.0

1.5

2.0

2.5

1.0

1.5

2.0

2.5

3.0

3.5

INPUT VOLTAGE (V)

EN RISE

EN FALL

Figure 33. Typical EN Thresholds vs. Input Voltage (VIN)

TIMING

Turn-on delay is defined as the interval between the time that

VEN exceeds the rising threshold voltage and when VOUT rises to

~10% of its final value. The ADP199 includes circuitry that has a

typical 1 ms turn-on delay, and a controlled rise time to limit the

VIN inrush current. As shown in Figure 34 and Figure 35, the turn-

on delay is nearly independent of the input voltage.

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