TC1301A Datasheet, PDF(15/28 Page) Microchip Technology – Dual LDO with Microcontroller RESET Function

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TC1301A Datasheet, PDF (15/28 Pages) Microchip Technology – Dual LDO with Microcontroller RESET Function

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5.10 TC1301A SHDN2 Timing

VOUT1 will rise independent of the level of SHDN2 for

the TC1301A. Figure 5-1 is used to define the wake-up

time from shutdown (tWK) and the settling time (tS). The

wake-up time is dependant upon the frequency of

operation. The faster the SHDN pin is pulsed, the

shorter the wake-up time will be.

VIN

twk

SHDN2

VOUT1

VOUT2

FIGURE 5-1:

TC1301A Timing.

5.11 TC1301B SHDN1 / SHDN2 Timing

For the TC1301B, the SHDN1 input pin is used to

control VOUT1. The SHDN2 input pin is used to control

VOUT2, independent of the logic input on SHDN1.

VIN

twk

SHDN1

VOUT1

SHDN2

VOUT2

FIGURE 5-2:

TC1301B Timing.

TC1301A/B

5.12 VDET and RESET Operation

The TC1301A/B integrates an independent voltage

reset monitor that can be used for low-battery input

voltage detection or a microprocessor Power-On Reset

(POR) function. The input voltage for the detector is

different for the TC1301A than it is for the TC1301B.

For the TC1301A, the input voltage to the detector is

pin 8 (VDET). For the TC1301B, the input voltage to the

detector is internally connected to the output of LDO #1

(VOUT1). The detected voltage is sensed and compared

to an internal threshold. When the voltage on the VDET

pin is below the threshold voltage, the RESET output

pin is low. When the voltage on the VDET pin rises

above the voltage threshold, the RESET output will

remain low for typically 300 ms (RESET time-out

period). After the RESET time-out period, the RESET

output voltage will transition from the low output state

to the high output state if the detected voltage pin

remains above the threshold voltage.

The RESET output will be driven low within 180 Âµs of

VDET going below the RESET voltage threshold. The

RESET output will remain valid for detected voltages

greater than 1.2V overtemperature.

5.13 TC1301A RESET Timing

Figure 5-3 shows the RESET timing waveforms for the

TC1301A. This diagram is also used to define the

RESET active time-out period (tRPU) and the VDET

RESET delay time (tRPD).

VTH

VDET

RESET Time

VOH

RESET

TRPD

VOL

FIGURE 5-3:

TC1301A RESET Timing.

DS21798B-page 15

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