LT1763MPDE-3 View Datasheet(PDF) - Linear Technology

Part Name

Description

MFG CO.

LT1763MPDE-3

500mA, Low Noise, LDO Micropower Regulators

Linear Technology 

LT1763 Series

APPLICATIONS INFORMATION

The top resistor of the resistor divider must be chosen to

limit the current into the ADJ pin to less than 5mA when

the ADJ pin is at 7V. The 13V difference between output

and ADJ pin divided by the 5mA maximum current into the

ADJ pin yields a minimum top resistor value of 2.6k.

In circuits where a backup battery is required, several

different input/output conditions can occur. The output

voltage may be held up while the input is either pulled

to ground, pulled to some intermediate voltage or is left

open-circuit. Current flow back into the output will follow

the curve shown in Figure 7.

When the IN pin of the LT1763-X is forced below the OUT

pin, or the OUT pin is pulled above the IN pin, input cur-

rent will typically drop to less than 2μA. This can happen

if the input of the device is connected to a discharged

(low voltage) battery and the output is held up by either

a backup battery or a second regulator circuit. The state

of the SHDN pin will have no effect on the reverse output

current when the output is pulled above the input.

100

TJ = 25°C

90 VIN = 0V

CURRENT FLOWS

80 INTO OUTPUT PIN

70 VOUT = VADJ (LT1763)

60

LT1763

LT1763-1.8

50 LT1763-2.5

40 LT1763-3

LT1763-1.5

30

20

10

LT1763-5

LT1763-3.3

0

0 1 2 3 4 5 6 7 8 9 10

OUTPUT VOLTAGE (V)

1763 F07

Figure 7. Reverse Output Current

1763fg

19

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