MB3793-30A View Datasheet(PDF) - Cypress Semiconductor

Part Name

Description

View to exact match

MB3793-30A

Power Voltage Monitoring IC with Watchdog Timer Datasheet

Cypress Semiconductor 

MB3793-30A

4. Block Description

1. Comp. S

Comp. S is a comparator with hysteresis to compare the reference voltage with a voltage (VS) that is the result of

dividing the power voltage (VCC) by resistors 1 and 2. When VS falls below 1.24 V, a reset signal is output.

This function enables the MB3793 to detect an abnormality when the power is cut or falls abruptly.

2. Output Circuit

The output circuit contains a RESET output control comparator that compares the voltage at the CTP pin to the

threshold voltage to release the RESET output if the CTP pin voltage exceeds the threshold value.

Since the reset (RESET) output buffer has CMOS organization, no pull-up resistor is needed.

3. Pulse Generator

The pulse generator generates pulses when the voltage at the CK1 and CK2 clock pins changes to High from Low

level (positive-edge trigger) and exceeds the threshold voltage; it sends the clock signal to the watchdog timer.

4. Watchdog Timer

The watchdog timer can monitor two clock pulses. Short-circuit the CK1 and CK2 clock pins to monitor a single clock

pulse.

5. Inhibition Pin

The inhibition (INH) pin forces the watchdog timer on/off. When this pin is High level, the watchdog timer is stopped.

6. Logic Circuit

The logic circuit contains flip-flops.

Flip-flop RSFF1 controls the charging and discharging of the power-on reset hold time setting capacitor (CTP).

Flip-flop RSFF2 turns on/off the circuit that accelerates charging of the power-on reset hold time setting capacitor

(CTP) at a reset. The RSFF2 operates only at a reset; it does not operate at a power-on reset when the power is

turned on.

5. Absolute Maximum Ratings

Parameter

Power supply voltage*

Input voltage*

Reset output voltage*

Reset output current

Power dissipation

Storage temperature

CK1

CK2

INH

RESET

Symbol

VCC

VCK1

VCK2

IINH

VVOOLH

IIOOLH

PD

Tstg

Conditions

−

−

−

−

−

−

Ta ≤ +85°C

−

Min

−0.3

−0.3

−0.3

−10

−

−55

Rating

Unit

Max

+7

V

VCC + 0.3 ( ≤ +7) V

VCC + 0.3 ( ≤ +7) V

+10

mA

200

mW

+125

°C

* : The voltage is based on the ground voltage (0 V).

WARNING:

1. Semiconductor devices may be permanently damaged by application of stress (including, without limitation, voltage,

current or temperature) in excess of absolute maximum ratings.Do not exceed any of these ratings.

Document Number: 002-08554 Rev. *C

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