Preliminary
RT9801
User Programmable Micro-Power Voltage Detectors
General Description
Features
The RT9801 is a micro-power voltage detector
supervising the power supply voltage level for
microprocessors (µP) or digital systems. It provides
user programmable threshold levels with 0.1V step
ranging from 1.5V to 5V, which covers most digital
applications. It features low supply current of 3µA.
Selection of VTH is easily achieved through 3 pins
connected to GND, VDD or floating for different
threshold voltage settings. Two versions of threshold
voltages, 1.5V ~ 4V and 2.5V ~ 5V, which are
programmed in factory are offered by customer
demands.
z User Programmable Threshold 1.5V to 5V in
0.1V Step with ±3% Accuracy
z Low Supply Current 3µA
z Quick Reset within 20µS
z Built-in Recovery Delay 200mS
z Low Functional Supply Voltage 0.9V
z Small SOT-26 Package
Applications
z Computers
z Controllers
z Intelligent Instruments
z Critical µP and µC Power Monitoring
z Portable/Battery-Powered Equipment
The RT9801 performs supervisory function by
sending out a reset signal whenever the VDD voltage
falls below a preset threshold level. This reset signal
will last the whole period before VDD recovering.
Reset signal will release after VDD is recovered and
lasts for the whole period of Reset Active Time-out
period.
Pin Configurations
Part Number
Pin Configurations
TOP VIEW
RT9801ꢀCE
6
1
5
2
4
3
1. VSET0
2. GND
3. RESET
4. VDD
(Plastic SOT-26)
RT9801 is N-channel, open-drain output and
provided in SOT-26 package.
5. VSET2
6. VSET1
Ordering Information
RT9801ꢀ ꢀ ꢀ
Package Type
E : SOT-26
Typical Application Circuit
Operating temperature range
C: Commercial standard
VSET0
VSET1
µP
RT9801
Reset Threshold
A : 2.5V~5V
GND
GND
VSET2
VDD
VDD
B : 1.5V~4V
RESET
RESET
Marking Information
Pull Up
Part Number
RT9801ACE
RT9801BCE
Marking
RT9801B V
= 2.5V in this example
TH
1J
1K
DS9801-02 August 2002
www.richtek.com
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