MICREL MIC1832N, MIC1832M Datasheet

1

The MIC1832 is a multifunction circuit which monitors
microprocessor activity, external reset and power
supplies in microprocessor based systems. The circuit
functions include a watchdog timer, power supply
monitor, microprocessor reset, and manual pushbutton
reset input.

The power supply line is monitored with a comparator
and an internal voltage reference. RST is forced low
when an out-of-tolerance condition exists and remains
asserted for at least 250ms after V

CC

rises above the
threshold voltage (2.55V or 2.88V). The RST pin will
remain logic low with V

CC

as low as 1.4V.

The Watchdog input (ST) monitors µP activity and will
assert RST if no µP activity has occurred within the

watchdog timeout period. The watchdog timeout period
is selectable with a nominal periods of 150, 600, or
1200 milliseconds.

MIC1832N - 8 Lead Plastic DIP Package
MIC1832M - 8 Lead Plastic SOIC Package

Part Package Temp. Range

MIC1832N 8-Lead PDIP -40°C to +85°C

MIC1832M 8-Lead SOIC -40°C to +85°C

·

Automotive Systems

·

Intelligent Instruments

·

Critical Microprocessor Power Monitoring

·

Battery Powered Computers

·

Controllers

·

Power OK/Reset Time Delay, 250ms min.

·

Watchdog Timer, 150ms, 600ms, or

1.2s typical

·

Precision Supply Voltage Monitor, Select
Between 5% or 10% of Supply Voltage

·

Available in 8-pin Surface Mount (SO)

·

Debounced External Reset Input

·

Low Supply Current,

< 18µA Typ.

Typical Operating Circuit

Features

Description

Pin Configuration

Ordering Information

Typical Applications

Top View

MIC1832 µP Supervisory Circuit

MIC1832

µP Supervisory Circuit

PBRST

1

TD

2

MIC1832

TOL

3

GND

4

8

V

CC

7

ST

RST

6

RST

5

V

CC

TD

V

CC

MIC1832

PBRST

GND

TOL

ST

RST

V

I/O

RESET

CC

µP

MIC1832 µP Supervisory Circuit

2

Electrical Characteristics

VCC= 3 to 5.5 V, TA= Operating Temperature Range, unless otherwise noted.

Parameter Conditions Min Typ Max Units

Supply Voltage Range V

CC

5.5 V

Supply Current I

CC

@ V

CC

= 5V (See Note 1) 18 30 µA

I

CC

@ V

CC

= 3.3V (See Note 1) 15 25 µA

ST and PBRST Input Levels V

IH

(See Note 2)

2.0

VCC+ 0.3 V

V

IH

(See Note 3)

VCC - 0.4

VCC+ 0.3 V

V

IL

-0.3 0.5

Input Leakage, ST (See Note 4) I

IL ±1

µA

Output Voltage, RST, RST I

SOURCE

= 350µA, V

CC

= 3.3V 2.4 V

Output Voltage, RST, RST I

SINK

= 10mA, VCC= 3.3V 0.4 V

Output Voltage, RST V

CC

= 1.4V, I

SINK

= 50µA 0.3 V

V

CC

5% Trip Point (Reset TOL = Gnd 2.80 2.88 2.97 V

Threshold Voltage)

V

CC

10% Trip Point (Reset TOL = V

CC

2.47 2.55 2.64 V

Threshold Voltage)

Input Capacitance, ST, TOL C

IN

(See Note 5) 5 pF

Output Capacitance, RST, RST C

OUT

(See Note 5) 7 pF

Absolute Maximum Ratings

Terminal Voltage

VCC, . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7.0V

All Other Inputs . . . . . . . . . . . . -0.3V to (VCC+ 0.3V)

Input Current

VCC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250mA

Gnd, All Other Inputs . . . . . . . . . . . . . . . . . . . . 25mA

Operating Temperature Range

MIC1832_ . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to 85°C

Storage Temperature Range . . . . . . . . . . . . .-65°C to 150°C

Lead Temperature (Soldering - 10 sec.) . . . . . . . . . . . 300°C

Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . 700mW

Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality at or above these limits is not implied. Exposure to absolute
maximum ratings for extended periods may affect device reliability. Operating ranges define those limits between which the functionality of the device is guaranteed.

MIC1832 µP Supervisory Circuit

3

Note 1: ICCis measured with PBRST and all outputs open and inputs within 0.5V of supply rails.
Note 2: Measured with VCC ≥ 2.7V.
Note 3: Measured with VCC < 2.7V.
Note 4: PBRST has an internal pull-up resistor to V

CC

(typ. 40kΩ).

Note 5: Guaranteed by design at TA= 25

°C.

Note 6: PBRST must be held low for a minimum of 20ms to guarantee a reset.
Note 7: V

CC

falling at 8.5mv/µs.

A.C. Electrical Characteristics

VCC= 3 to 5.5 V, TA= Operating Temperature Range, unless otherwise noted.

Parameter Conditions Min Typ Max Units

PBRST Min. Pulse Width, t

PB

PBRST = VIL(see note 6) 20 ms

PBRST Delay, t

PBD

1 4 20 ms

Reset Active Time, t

RST

250 610 1000 ms

ST Pulse Width, t

ST

20 ns

ST Timeout Period, t

TD

TD = 0V 62.5 150 250 ms
TD = Open 250 600 1000
TD = V

CC

500 1200 2000

VCCFall Time, t

F

40

µs

VCCRise Time, t

R

0

ns

VCCDetect to RST Low V

CC

Falling (see note 7) 5 8 µs

and RST High, t

RPD

VCCDetect to RST High VCCRising 250 610 1000 ms
and RST Low, t

RPU