Preliminary
RT9802
DS9802-00 January 2002
www.richtek.com
1
User Programmable Micro-Power Voltage Detectors
General Description
The RT9802 is a micro-power voltage detector
supervising the power supply voltage level for
microprocessors (
P) 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 3
A.
Selection of V
TH
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.
The RT9802 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.
RT9802 is CMOS, active-low output and
provided in
SOT-26 package.
Ordering Information
RT9802
Features
User Programmable Threshold 1.5V to 5V in
0.1V Step with
3% Accuracy
Low Supply Current 3
A
Quick Reset within 20
S
Built-in Recovery Delay 200mS
Low Functional Supply Voltage 0.9V
Small SOT-26 Package
Applications
Computers
Controllers
Intelligent Instruments
Critical
P and
C Power Monitoring
Portable/Battery-Powered Equipment
Pin Configurations
Part Number
Pin Configurations
RT9802 CE
(Plastic SOT-26)
TOP VIEW
1. VSET0
2. GND
3. RESET
4. VDD
5. VSET2
6. VSET1
Typical Application Circuit
Operating temperature range
C: Commercial standard
Package Type
E : SOT-26
Reset Threshold
A : 2.5V~5V
B : 1.5V~4V
VSET0
GND
RESET
VSET1
VSET2
VDD
GND
RESET
VDD
RT9802B V
TH
= 2.5V in this example
P
RT9802
6
4
3
2
1
5
RT9802
Preliminary
www.richtek.com
DS9802-00 January 2002
2
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
VSET
CMP
TIMER
VDD
POR
Threshold Voltage Setting
Power On Reset
Internal Clock
VSET0
VSET1
VSET2
N
VDD
RESET
P
Preliminary
RT9802
DS9802-00 January 2002
www.richtek.com
3
Absolute Maximum Ratings
Terminal Voltage (with Respect to GND)
VDD
-0.3V to 6.0V
All Other Inputs
-0.3V to VDD+0.3V
Input Current, VDD
20mA
Continuous Power Dissipation, P
D
@ T
A
= 25
C
SOT-26
0.25W
Operating Junction Temperature Range
-40
C ~ 125
C
Storage Temperature Range
-65
C ~ 125
C
Package Thermal Resistance
SOT-26,
JA
250
C /W
Lead Temperature (Soldering, 5sec.)
260
C
Electrical Characteristics
(VDD
= 3.0, unless specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
Operating VDD (V
OUT
) Range
V
DD
0.9
--
6
V
--
3
Supply Current
I
DD
V
DD
= 1.5V ~ 3.5V, I
OUT
= 0
V
DD
= 3.5V ~ 5V, I
OUT
= 0
3.3
A
Reset Threshold
V
TH
T
A
= 27
C
--
Note1
--
V
Threshold Voltage Accuracy
V
TH
T
A
= 27
C
--
3
%
V
CC
Drop to Reset Delay
t
RD
Drop = -125mV
--
--
20
S
Reset Active Time Out Period
t
RP
V
DD
1.02
V
TH
,
Programmable
--
200
--
mS
V
IL
T
A
= 27
C
--
0.2V
DD
--
VSET Pin Input Threshold
V
IH
T
A
= 27
C
--
0.85V
DD
--
V
RESET Output Voltage
V
OL
V
DD
< V
TH
, I
SINK
= 3.5mA
--
0.4
--
V
RT9802
Preliminary
www.richtek.com
DS9802-00 January 2002
4
Note 1: Pin Conditions for Programmable Threshold Voltage Setting
RT9802A
RT9802B
VSET0 input
VSET1 input
VSET2 input
5
4
V
DD
V
DD
V
DD
4.9
3.9
V
DD
V
DD
floating
4.8
3.8
V
DD
V
DD
GND
4.7
3.7
V
DD
floating
V
DD
4.6
3.6
V
DD
floating
floating
4.5
3.5
V
DD
floating
GND
4.4
3.4
V
DD
GND
V
DD
4.3
3.3
V
DD
GND
floating
4.2
3.2
V
DD
GND
GND
4.1
3.1
floating
V
DD
V
DD
4
3
floating
V
DD
floating
3.9
2.9
floating
V
DD
GND
3.8
2.8
floating
floating
V
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
DD
V
DD
3.1
2.1
GND
V
DD
floating
3
2
GND
V
DD
GND
2.9
1.9
GND
floating
V
DD
2.8
1.8
GND
floating
floating
2.7
1.7
GND
floating
GND
2.6
1.6
GND
GND
V
DD
2.5
1.5
GND
GND
floating
V
DD
: bond to V
DD
; 0: bond to GND; f: no bonding
Preliminary
RT9802
DS9802-00 January 2002
www.richtek.com
5
Package Information
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
0.889
1.295
0.035
0.051
A1
--
0.152
--
0.006
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
b
B
C
D
L
H
A1
e
A
RT9802
Preliminary
www.richtek.com
DS9802-00 January 2002
6
RICHTEK TECHNOLOGY CORP.
Headquarter
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
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.com
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