ADP160/ADP161

Rev. 0 | Page 14 of 20

To guarantee the performance of the ADP160/ADP161, it is

imperative that the effects of dc bias, temperature, and tolerances

on the behavior of the capacitors are evaluated for each.

ENABLE FEATURE

The ADP160/ADP161 use the EN pin to enable and disable the

VOUT pin under normal operating conditions. As shown in

Figure 33, when a rising voltage on EN crosses the active threshold,

VOUT turns on. When a falling voltage on EN crosses the inactive

threshold, VOUT turns off.

4.5

3.5

2.5

4.0

3.0

2.0

1.5

0.5

1.0

0

0.5

0.7

0.9

1.1

1.3

1.5

EN VOLTAGE (V)

Figure 33. Typical EN Pin Operation

As shown in Figure 33, the EN pin has hysteresis built in. 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 are derived from the VIN

voltage. Therefore, these thresholds vary with changing input

voltage. Figure 34 shows typical EN active/inactive thresholds

when the input voltage varies from 2.2 V to 5.5 V.

1.1

1.0

0.9

0.8

0.7

0.6

0.5

2.0

2.5

3.0

3.5

EN RISE

EN FALL

4.0

4.5

5.0

INPUT VOLTAGE (V)

Figure 34. Typical EN Pin Thresholds vs. Input Voltage

The start-up and shutdown behavior of the ADP160 is shown in

Figure 35 and Figure 36.

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

04

4000

3500

3000

2500

2000

1500

1000

500

1.2V

2.5V

3.3V

500

TIME (µs)

EN

Figure 35. Typical Start-Up Behavior

4.5

3.5

4.0

3.0

2.5

2.0

1.5

1.0

0.5

0

01

800

600

400

200

1.2V

4.2V

000

TIME (µs)

EN

Figure 36. Typical Shutdown Behavior

CURRENT LIMIT AND THERMAL OVERLOAD

PROTECTION

The ADP160/ADP161 are protected against damage due to

excessive power dissipation by current and thermal overload

protection circuits. The ADP160/ADP161 are designed to

current limit when the output load reaches 320 mA (typical).

When the output load exceeds 320 mA, the output voltage is

reduced to maintain a constant current limit.

Thermal overload protection is included, which limits the junction

temperature to a maximum of 150°C (typical). Under extreme

conditions (that is, high ambient temperature and power dissipation),

when the junction temperature starts to rise above 150°C, the

output is turned off, reducing the output current to zero. When

the junction temperature drops below 135°C, the output is turned

on again and the output current is restored to its nominal value.