Preliminary
RT9801
User Programmable Micro-Power Voltage Detectors
General Description
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 V
is easily achieved through 3 pins
TH
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.
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.
RT9801 is N-channel, open-drain output and
provided in SOT-26 package.
Ordering Information
Features
z
User Programmable Threshold 1.5V to 5V in
0.1V Step with ±±±±3% Accuracy
z
Low Supply Current 3µµµµA
z
Quick Reset within 20µµµµS
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
Pin Configurations
Part Number Pin Configurations
321
TOP VIEW
1. VSET0
2. GND
3. RESET
4. VDD
5. VSET2
6. VSET1
RT9801CE
(Plastic SOT-26)
64
5
RT9801
Typical Application Circuit
Package Type
E : SOT-26
Operating temperature range
C: Commercial standard
P
Reset Threshold
A : 2.5V~5V
B : 1.5V~4V
DS9801-00 January 2002 www.richtek-ic.com.tw
µ
GND
VDD
RESET
RT9801B V
VSET0
GND
RESET
Pull Up
= 2.5V in this example
TH
VSET1
RT9801
VSET2
VDD
1
RT9801
Pin Description
Pin Name Pin Function
VSET0 Threshold Voltage Selection Pin 1
GND Ground Pin
RESET Reset Pulse Output, Negative Pulse
VDD Power Pin
VSET1 Threshold Voltage Selection Pin 2
VSET2 Threshold Voltage Selection Pin 3
Function Block Diagram
Internal Clock
VDD
Preliminary
VSET0
VSET1
VSET2
Threshold Voltage Setting
VSET
CMP
POR
Power On Reset
TIMER
N
RESET
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Preliminary
RT9801
Absolute Maximum Ratings
z Terminal Voltage (with Respect to GND)
VDD -0.3V to 6.0V
All Other Inputs -0.3V to VDD+0.3V
z Input Current, VDD 20mA
z Continuous Power Dissipation, P
@ TA = 25°C
D
SOT-26 0.25W
z Operating Junction Temperature Range -40°C ~ 125°C
z Storage Temperature Range -65°C ~ 125°C
z Package Thermal Resistance
SOT-26, θ
z Lead Temperature (Soldering, 5sec.) 260°C
JA
250°C /W
Electrical Characteristics
(VDD = 3.0, unless specified)
Parameter Symbol Test Conditions Min Typ Max Units
Operating VDD (V
) Range V
OUT
Supply Current
Reset Threshold
Threshold Voltage Accuracy
VCC Drop to Reset Delay t
Reset Active Time Out Period
VSET Pin Input Threshold
RESET Output Voltage
I
DD
V
∆V
RD
t
RP
V
V
V
DD
TH
IL
IH
OL
0.9 -- 6 V
VDD = 1.5V ~ 3.5V, I
V
= 3.5V ~ 5V, I
DD
TA = 27°C
TA = 27°C
TH
OUT
OUT
= 0
= 0
-- 3
-- Note1 -- V
-- 3 %
Drop = -125mV -- -- 20
VDD ≥ 1.02×VTH,
Programmable
TA = 27°C
TA = 27°C
V
< VTH, I
DD
SINK
= 3.5mA
-- 200 -- mS
--
--
-- 0.4 -- V
0.15V
0.85V
DD
DD
3.3
--
--
µA
µS
V
DS9801-00 January 2002 www.richtek-ic.com.tw
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RT9801
Preliminary
Note 1: Pin Conditions for Programmable Threshold Voltage Setting
RT9801A RT9801B Vset0 input Vset1 input Vset2 input
54VDDV
4.9 3.9 V
4.8 3.8 V
4.7 3.7 V
4.6 3.6 V
4.5 3.5 V
4.4 3.4 V
4.3 3.3 V
4.2 3.2 V
DD
DD
DD
DD
DD
DD
DD
DD
4.1 3.1 floating V
4 3 floating V
3.9 2.9 floating V
DD
V
DD
V
DD
floating V
floating floating
floating GND
GND V
GND floating
GND GND
DD
DD
DD
3.8 2.8 floating floating V
V
DD
floating
GND
DD
DD
V
DD
floating
GND
DD
3.7 2.7 floating floating floating
3.6 2.6 floating floating GND
3.5 2.5 floating GND V
DD
3.4 2.4 floating GND floating
3.3 2.3 floating GND GND
3.2 2.2 GND V
3.1 2.1 GND V
32GNDVDDGND
2.9 1.9 GND floating V
2.8 1.8 GND floating floating
2.7 1.7 GND floating GND
2.6 1.6 GND GND V
2.5 1.5 GND GND floating
VDD: bond to VDD; 0: bond to GND; f: no bonding
DD
DD
V
DD
floating
DD
DD
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4
Package Information
D
Preliminary
RT9801
C
b
A
e
B
A1
Symbol
A 0.889 1.295 0.035 0.051
A1 -- 0.152 -- 0.006
Dimensions In Millimeters Dimensions In Inches
Min Max Min Max
H
L
B 1.397 1.803 0.055 0.071
b 0.356 0.559 0.014 0.022
C 2.591 2.997 0.102 0.118
D 2.692 3.099 0.106 0.122
e 0.838 1.041 0.033 0.041
H 0.102 0.254 0.004 0.010
L 0.356 0.610 0.014 0.024
SOT- 26 Surface Mount Package
DS9801-00 January 2002 www.richtek-ic.com.tw
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RT9801
Preliminary
RICHTEK TECHNOLOGY CORP.
Headquarter
6F, No. 35, Hsintai Road, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5510047 Fax: (8863)5537749
www.richtek-ic.com.tw DS9801-00 January 2002
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek-ic.com.tw
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