R3111x

13

 R3111E (TO-92) is the discontinued product as of April, 2017.

 Operation of R3111xxxxB

Vref

Ra

Rb

Rc

VDD

OUT

GND

Tr.1

Nch

Comparator

OUT pin should be pulled-up to

VDD or an external voltage level.

Block Diagram (R3111xxxxB)

tPLH

GND

GND

VDDL

-VDET

+VDET

Detector Threshold

Released Voltage

Minimum Operating Voltage

Pull-up Voltage

1

2

3

A

B

Detector Threshold

Hysteresis

Supply Voltage

(VDD)

Output Voltage

(VOUT)

Step

1

2

3

Comparator (

)

Pin Input Voltage

I

II

I

Comparator Output

L

H

L

Tr.1

OFF ON OFF

Output Tr.

Nch

ON OFF ON

I

VDD

Rb

Rc

Ra

RbRc

II

VDD

Rb

Ra

Rb

Operation Diagram

 Explanation of operation

Step 1. The output voltage is equal to the GND level.

Step 2. At Point “A”, Vref  

 VDD(RbRc)/(RaRbRc) is true, as a result, the output of comparator is reversed

from "L" to "H", therefore the output voltage becomes the pull-up voltage. The voltage level of Point A

means a detector threshold voltage (

VDET).

Step 3. At Point “B”, Vref  

 VDDRb/(RaRb) is true, as a result, the output of comparator is reversed from "H" to

"L", then the output voltage is equal to the GND level. The voltage level of Point B means a released

voltage (

VDET).

) The difference between a released voltage and a detector threshold voltage is a detector threshold hysteresis.

Output

Delay Time