R3112Q15A-TR View Datasheet(PDF) - RICOH Co.,Ltd.

Part Name

Description

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R3112Q15A-TR

LOW VOLTAGE DETECTOR WITH OUTPUT DELAY

RICOH Co.,Ltd. 

s OPERATION

Current Source

Comparator

Ra -

RD

+

Rb

Vref

Rc

Tr.1

Tr.2

Schmitt Trigger

VDD

Pch

OUT

Nch

GND

Output Capacitor

CD

Fig. 1 Block Diagram with an external capacitor

1

Released Voltage+VDET

Detector Threshold-VDET

A

Supply Voltage

(VDD)

VDDL

Minimum Operating

Voltage

GND

2

3

4

HYSTERESIS RANGE

5

B

Output Voltage

(OUT)

Delay Time

Operation Status

12

3

45

Comparator(-) Pin

Input Voltage

Ι

ΙΙ

ΙΙ

ΙΙ

Ι

Comparator Output L

H Indefinite H

L

Tr.1, 2

OFF ON Indefinite ON OFF

Nch

Output Tr.

Pch

OFF ON Indefinite ON OFF

ON OFF Indefinite OFF ON

GND

Fig. 2 Operation Diagram

Ι

Rb+Rc ×VDD

Ra+Rb+Rc

ΙΙ

Rb ×VDD

Ra+Rb

1. Output Voltage is equal to Supply Voltage. (As for Nch Open Drain Type, equal to pull-up voltage.)

2. When the Supply Voltage is down to the detector threshold voltage level(Point A),

Vref≥VDD×(Rb+Rc)/(Ra+Rb+Rc) is true, then output of the comparator is reversed from “L” to “H”, therefore

Output Voltage becomes GND level.

3. When the Supply Voltage is lower than Minimum Operating Voltage, the operation of Output Transistor is

indefinite. In the case of Nch Open Drain Type, Output Voltage is equal to pull-up Voltage.

4. Output Voltage becomes GND level.

5. When the Supply Voltage is higher than released voltage (Point B), Vref≤VDD×Rb/(Ra+Rb) is true, then

Output of the comparator reaches the threshold level, and Output of Shmitt Trigger is reversed from “H” to

“L”, then Output Voltage is equal to Supply Voltage. (As for Nch Open Drain Type, equal to pull-up voltage.)

*) The difference between Released Voltage and Detector Threshold Voltage means Hysteresis Range

Voltage.

Rev. 1.10

-2-

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