EM MICROELECTRONIC
- MARIN SA
EM6323/24
Reset Circuit with Manual Reset and Watchdog
Description
The EM6323/24 are low power, high precision reset ICs
featuring a manual reset and a watchdog inputs. They have
different threshold voltages and several timeout reset periods
(t
POR
) and watchdog timeout periods (t
WD
) for maximum
flexibility in the application. EM6323 has a manual reset (
MR
with internal pull-up) and a watchdog input pins. EM6324 has
only a watchdog input pin (WDI). The watchdog function can
be disabled by driving WDI with a three-state driver or by
leaving WDI unconnected. This is useful when the MCU is in
sleep mode.
Small SOT23-5L package as well as ultra-low supply current
of 3.8µA make the EM6323 and the EM6324 an ideal choice
for portable and battery-operated devices.
Features
!
!
!
!
!
!
!
Ultra-low supply current of 3.8µA (V
DD
=3.3V)
Operating temperature range: -40°C to +125°C
±1.5%
reset threshold accuracy
11 reset threshold voltages V
TH
: 4.63V, 4.4V, 3.08V,
2.93V, 2.63V, 2.2V, 1.8V, 1.66V, 1.57V, 1.38V, 1.31V
200ms reset timeout period (1.6ms, 25ms, 1600ms on
request)
1.6s watchdog timeout period (6.2ms, 102ms, 25.6s on
request)
3 reset output options:
Active-low
RESET
push-pull
Active-low
RESET
open-drain
Active-high
RESET
push-pull
Detection of microcontroller in sleep mode
Typical Application
V
DD
V
DD
RESET
RESET
*
V
DD
RESET
RESET
!
Applications
!
!
!
!
!
!
!
EM632x
MR
GND
WDI
MPU, DSP
I/O
GND
GND
*
R
EXT
for open-drain version only
Fig. 1
Block Diagram
V
DD
Oscillator
Workstations
Point of sales (POS)
Personal computers
Routers, hubs and switches
Handheld GPS
Vending machines and ATM
Automotive systems
Pin Configuration
RESET
RESET
+
Voltage
Reference
-
Reset
Logic
+ Timer
EM6323
RESET
GND
MR
1
2
3
(manual reset,
watchdog)
5
V
DD
EM6324
push-pull/open-drain
(watchdog)
5 V
DD
RESET
GND
EM6323
MR
GND
WDI
Transition
Detector
Filter
2
3
EM6324
1
4
WDI
RESET
push-pull
4
WDI
Watchdog Logic
+ Timer
SOT23-5
Fig. 2
top view
SOT23-5
top view
Fig. 3
Pin Description
SOT23-5L
EM6323 EM6324
1
2
3
-
4
5
1
2
-
3
4
5
Name
RESET
Function
Active-low
RESET
output (push-pull or open-drain)
Ground
Manual Reset input with an internal pull-up 30kΩ resistor. Reset remains active as long as
MR
is low
and for t
POR
after returns high.
MR
can be driven with a CMOS output or shorted to ground with a switch
Active-high RESET output (push-pull)
Watchdog input. WDI must be driven with a CMOS output. If the microcontroller I/O is put in a high
impedance condition, the circuit will detect this condition as a microcontroller in sleep mode and prevent
its watchdog from timing out
Supply Voltage (5.5V max.)
GND
MR
RESET
WDI
V
DD
Copyright
©
2006, EM Microelectronic-Marin SA
03/06 - rev.H
1
www.emmicroelectronic.com
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
