R3131N16BC8-TR View Datasheet(PDF) - RICOH Co.,Ltd.

Part Name

Description

Manufacturer

R3131N16BC8-TR

Low Voltage Detector with Built-in Delay Circuit

RICOH Co.,Ltd. 

• Operation of R3131N Series

Ra

Vref Rb

+

Delay

-

Circuit

Comparator

Block Diagram

1

2

3

Supply

Voltage

A

(VDD)

R3130N/R3131N

VDD

Pch

OUT

Nch

⋅ CMOS output type

OUT pin is connected to the drain of

Nch Tr. and Pch Tr. in this IC.

⋅ Nch open drain output type: I

OUT pin is connected to the drain of

Nch Tr. in this IC. (OUT pin should be

pulled up to VDD or an external voltage

level.)

GND

4

5

B

Detector Threshold(VDET)

=Released Voltage

Minimum Operating

Voltage(VDDL)

GND

Output

Voltage

(OUT)

Tdelay

GND

Operation Diagram

In the above diagram,

1 Output voltage becomes equal to GND level.

2When supply voltage is down to the detector threshold level (Point A), Vref >= VDD× Rb/(Ra+Rb) is true. Then,

output of the comparator is reversed, thus output voltage becomes equal to supply voltage (Nch open drain

output type; equal to pull-up Voltage).

3 When supply voltage is lower than minimum operating voltage, Output of transistor is indefinite, therefore

output is also indefinite.(Nch open drain output type; Output voltage level is equal to pull-up voltage.)

4 Output voltage is equal to supply voltage. (Nch open drain output type; equal to pull-up voltage.)

5 When supply voltage is higher than released voltage (Point B), Vref <= VDD× Rb/(Ra+Rb) is true. Then output

of the comparator is reversed, thus output voltage becomes equal to GND level after the output delay time.

∗ There is no hysteresis range between detector threshold and released voltage.

17

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