Preliminary
RT9808
Micro-Power Voltage Detectors
General Description
The RT9808 is a micro-power voltage detector
supervising the power supply voltage level for
microprocessors (µP) or digital systems. It provides
internally fixed threshold levels with 0.1V per step
ranging from 1.5V to 5V, which covers most digital
applications. It features low supply current of 3µA.
The RT9808 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.
Once VDD recovered up-crossing the threshold level,
the reset signal will be released if VDD is above
threshold and last for the whole period of reset active
time out.
RT9808 is n-channel, open-drain output.
Applications
Computers
z
Controllers
z
Intelligent Instruments
z
Critical µP and µC Power Monitoring
z
Portable/Battery-Powered Equipment
z
Ordering Information
RT9808-
Package Type
V : SOT-23
X : SOT-89
B : SOT-25
Features
z
Internally Fixed Threshold 1.5V to 5V in 0.1V Step
z ±
±2% Accuracy
±±
Low Supply Current 3µµµµA
z
Quick Reset within 20µµµµS
z
Built-in Recovery Delay 200mS
z
Low Functional Supply Voltage 0.9V
z
N-Channel Open Drain Output
z
Small 3-Pin SOT-23/SOT89 and 5-Pin SOT-25
z
Packages
Pin Configurations
Part Number Pin Configurations
RT9808-CV
(Plastic SOT-23)
RT9808-CX
(Plastic SOT-89)
RT9808-CB
(Plastic SOT-25)
3
2
1
123
54
3
21
TOP VIEW
1. RESET
2. GND
3. VDD
TOP VIEW
1. RESET
2. VDD
3. GND
TOP VIEW
1. RESET
2. VDD
3. GND
4. NC
5. NC
Typical Application Circuit
Operating temperature range
C: Commercial standard
Reset Threshold
15 : 1.5V
VDD
P
µ
Pull
Up
100K
RT9808
GND
VDD
16 : 1.6V
:
RESET
RESET
49 : 4.9V
50 : 5.0V
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RT9808
Pin Description
Pin Name Pin Function
GND Ground Pin
RESET Reset Pulse Output, Negative Pulse
VDD Power Pin
NC No Connected
Function Block Diagram
VDD
Preliminary
VSET
Threshold Voltage Setting
Power On Reset
CMP
POR
TIMER
RESET
N
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Preliminary
RT9808
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 Output Current, RESET 20mA
z Power Dissipation, P
SOT-23 0.25W
SOT-89 0.5W
SOT-25 0.25W
z Operating Junction Temperature Range -40°C ~ 125°C
z Storage Temperature Range -65°C ~ 125°C
z Package Thermal Resistance
SOT-23, θ
SOT-89, θ
SOT-89, θ
SOT-25, θ
z Lead Temperature (Soldering, 5sec.) 260°C
JA
JC
JA
JA
@ TA = 25°C
D
250°C /W
100°C /W
300°C /W
250°C /W
Electrical Characteristics
(VDD = 3.0, unless specified)
Parameter Symbol Test Conditions Min Typ Max Units
Operating VDD (V
Supply Current
Reset Threshold
Threshold Voltage Accuracy
VCC Drop to Reset Delay t
Reset Active Time Out Period
RESET Output Voltage
Note1: 1.5V ~ 5V, step 0.1V
) Range V
OUT
I
DD
V
∆V
RD
t
RP
V
DD
TH
OL
0.9 -- 6 V
VDD = 1.5V ~ 5V, I
TA = 27°C
TA = 27°C
TH
OUT
= 0
-- 3 --
-- Note1 -- V
-- -- 2 %
Drop = -125mV -- -- 20
VDD ≥ 1.02×V
V
< VTH, I
DD
TH
SINK
> 3.5mA
-- 200 -- mS
-- 0.4 -- V
µA
µS
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RT9808
Measuring Circuit
Preliminary
(1) Detection Voltage
V
DD
V
RT9808
(2) Current Consumption
A
V
DD
V
V
DD
V
SS
V
RT9808
DD
R (100kΩ)
OUT
OUT
Oscilloscope
(3) Output Transistor Current
V
DD
RT9808
OUT
P.G
V
SS
(4) Dynamic Response
V
DD
V
DD
V
RT9808
100k
CRT
CL
OUT
Ω
6V
A
SS
V
V
DS
V
SS
V
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Typical Operating Characteristics
Preliminary
RT9808
Nch Driver Output Current vs. V
7
6
5
(mA)
OUT
4
3
2
Output Current I
1
0
0 0.5 1 1.5 2 2.5 3
V
(V)
DS
RT9808-20CV
Nch Driver Output Current vs. V
18
15
(mA)
12
OUT
9
2.0V
6
Output Current I
3
0
0 0.5 1 1.5 2 2.5 3
1.5V
RT9808-30CV
VDS (V)
T
= 25°C
T
= 25°C
2.8V
DS
DS
Nch Driver Output Current vs. V
12
10
(mA)
8
OUT
6
4
Output Current I
2
0
0 0.5 1 1.5 2 2.5 3
1.5V
V
(V)
DS
2.0V
RT9808-24CV
Nch Driver Output Current vs. V
36
30
(mA)
24
OUT
18
2.5V
12
2.0V
Output Current I
6
0
01234
1.5V
RT9808-45CV
2.2V
T
3.0V
T
DS
= 25°C
DS
4.0V
3.5V
= 25°C
VDS (V)
Nch Driver output Current vs. V
40
32
(mA)
OUT
24
16
8
Output Current I
1.5V
0
012345
2.5V
2.0V
3.5V
3.0V
RT9808-50CV
4.0V
T
= 25°C
DS
4.5V
VDS (V)
Output Voltage vs. Input Voltage
7
T
= 25°C
6
(V)
5
OUT
4
3.0V
3
2
2.4V
2.0V
Output Voltage V
1
0
0.0 1.0 2.0 3.0 4.0 5.0 6.0
Input Voltage VIN (V)
5.0V
4.5V
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RT9808
µ
µ
µ
µ
µ
Preliminary
Supply Current vs. Input Voltage
4
3
( A)
SS
2
1
Supply Cur rent I
0
0123456
80 C
25 C
-30 C
RT9808-20CV
Input Voltage VIN (V)
Supply Current vs. Input Voltage
4
3
( A)
SS
2
°
80 C
°
25 C
°
-30 C
Supply Current vs. Input Voltage
4
3
( A)
SS
2
1
Supply Current I
0
0123456
80 C
25 C
-30 C
°
°
°
RT9808-24CV
Input Voltage VIN (V)
Supply Current vs. Input Voltage
5
°
80 C
°
25 C
-30 C
°
( A)
SS
4
3
2
1
Supply Current I
0
0123456
RT9808-30CV
Input Voltage VIN (V)
Supply Current vs. Input Voltage
5
°
80 C
4
°
( A)
SS
3
2
Supply Cur rent I
1
0
0123456
Input Voltage VIN (V)
25 C
-30 C
°
RT9808-50CV
Supply Cur rent I
1
0
0123456
RT9808-45CV
Input Voltage VIN (V)
Reset Threshold Deviation vs. Temp.
5.1
4.7
4.3
3.9
3.5
3.1
Threshold (V)
2.7
2.3
1.9
-40 -15 10 35 60 85
Temperture ( C)
°
4.5V
2.4V
5V
3V
2V
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Preliminary
RT9808
Nch Driver Output Current vs. Input Voltage
10
RT9808-20CV
= 0.5V
V
DS
8
°
(mA)
OUT
6
4
2
Output Current I
0
00.511.522.53
-30 C
25 C
°
80 C
°
Input Voltage VIN (V)
Nch Driver Output Current vs. Input Voltage
12
RT9808-30CV
V
= 0.5V
DS
10
°
(mA)
8
OUT
6
4
Output Current I
2
-30 C
25 C
80 C
°
°
Nch Driver Output Current vs. Input Voltage
10
RT9808-24CV
= 0.5V
V
DS
8
(mA)
OUT
6
4
2
Output Curre nt I
0
00.511.5 22.53
-30 C
25 C
80 C
Input Voltage VIN (V)
Nch Driver Output Current vs. Input Voltage
16
RT9808-45CV
= 0.5V
V
DS
14
°
12
(mA)
10
OUT
8
6
4
Output Current I
2
-30 C
°
25 C
80 C
°
0
00.511.522.5 33.5
Input Voltage VIN (V)
Nch Driver Output Current vs. Input Voltage
18
RT9808-50CV
V
= 0.5V
DS
15
(mA)
12
OUT
9
6
Output Curre nt I
3
0
0123456
Input Voltage VIN (V)
-30 C
25 C
80 C
°
°
°
0
012345
Input Voltage VIN (V)
Power-Up reset Timeout vs. Temp.
350
300
250
200
150
100
Power-Up Reset Timeout (ms)
50
-40 -15 10 35 60 85
Temperture ( C)
°
2V
2.4V
3V
4.5V
5V
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RT9808
µ
µ
µ
µ
µ
V
Preliminary
Power-Down Reset Delay vs. Temp.
4.0
3.0
2.0
V
drop
V
drop
1.0
Power-Down Reset Delay ( s)
0.0
-40 -15 10 35 60 85
V
drop
RT9808-20CV
Temperture ( C)
Power-Down Reset Delay vs. Temp.
1.5
1.2
= 200mV
V
0.9
0.6
0.3
Power-Down Reset Delay ( s)
0.0
-40 -15 10 35 60 85
drop
Temperture ( C)
V
drop
V
drop
RT9808-30CV
= 150mV
= 200mV
= 250mV
= 150mV
= 250mV
Power-Down Reset Delay vs. Temp.
3.0
2.5
2.0
1.5
V
1.0
0.5
Power-Down Reset Delay ( s)
0.0
-40 -15 10 35 60 85
drop
V
drop
V
drop
RT9808-24CV
Temperture ( C)
Power-Down Reset Delay vs. Temp.
1.5
1.2
0.9
0.6
0.3
Power-Down Reset Delay ( s)
0.0
-40 -15 10 35 60 85
Temperture ( C)
V
drop
= 200mV
V
drop
V
drop
RT9808-45CV
= 150mV
= 200mV
= 250mV
= 150mV
= 250mV
Power-Down Reset Delay vs. Temp.
1.5
1.2
0.9
0.6
0.3
Power-Down Reset Delay ( s)
0.0
-40 -15 10 35 60 85
V
= 200mV
drop
Temperture ( C)
°
V
drop
V
drop
RT9808-50CV
= 150mV
= 250mV
Output Delay Time vs. Load Capacitance
1000
(ms)
P
100
2.4
10
4.5V
5V
Output Delay Time t
2V
3V
1
0.0001 0.001 0.01 0.1
Load Capacitance C
OUT
(uF)
T
= 25°C
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Package Information
D
Preliminary
RT9808
A1
B
L
C
e
A
b
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
H
b 0.356 0.508 0.014 0.020
C 2.591 2.997 0.102 0.118
D 2.692 3.099 0.106 0.122
e 1.803 2.007 0.071 0.079
H 0.102 0.254 0.004 0.010
L 0.356 0.610 0.014 0.024
SOT-23 Plastic Surface Mount
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RT9808
Preliminary
D
D1
C
C1
e e
b
b1 b
B
A
A
H
Symbol
A 1.397 1.600 0.055 0.063
b 0.356 0.483 0.014 0.019
B 2.388 2.591 0.094 0.102
b1 0.406 0.533 0.016 0.021
C -- 4.242 -- 0.167
C1 0.787 1.194 0.031 0.047
D 4.394 4.597 0.173 0.181
D1 1.397 1.753 0.055 0.069
e 1.448 1.549 0.057 0.061
H 0.381 0.432 0.015 0.017
Dimensions In Millimeters Dimensions In Inches
Min Max Min Max
3-Lead SOT-89 Surface Mount
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D
Preliminary
RT9808
C
b
A
e
B
A1
Symbol
A 0.889 1.295 0.035 0.051
A1 0.000 0.152 0.000 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- 25 Surface Mount Package
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RT9808
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 DS9808-01 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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