Preliminary
RT9811
Micro-Power Voltage Detectors
General Description
The RT9811 is a micro-power voltage detector with
de-glitched manual reset input 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 2.5µA.
The RT9811 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 after a certain delay
time. A 5% hysteresis splits the rising and falling
threshold levels. To pull reset signal low manually,
just pull the manual reset input (MR) below the
specified V
RT9811 is provided in SOT-25 package.
level.
IL
Features
z
Internally Fixed Threshold 1.5V to 5V in 0.1V
Step
z ±
±2% Accuracy
±±
Low Supply Current 2.5µµµµA
z
No External Components Required
z
Quick Reset within 20µµµµS
z
Built-in Recovery Delay 400mS
z
100nS Glitch Immunity of Manual Reset Input
z
Low Functional Supply Voltage 0.9V
z
Small 4-Pin SOT-25 Package
z
Pin Configurations
Part Number Pin Configurations
RT9811-CB
(SOT-25)
54
321
TOP VIEW
1. GND
2. NC
3. RESET
4. MR
5. VDD
Applications
Computers
z
Controllers
z
Intelligent Instruments
z
Critical µP and µC Power Monitoring
z
Portable/Battery-Powered Equipment
z
Ordering Information
RT9811-
Package Type
B : SOT-25
Operating temperature range
C: Commercial standard
Reset Threshold
15 : 1.5V
16 : 1.6V
:
49 : 4.9V
50 : 5.0V
Typical Application Circuit
VDD
P
µ
RESET
RT9811
GND
RESET
VDD
MR
DS9811-00 June 2001 www.richtek-ic.com.tw
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RT9811
Pin Description
Pin Name Pin Function
GND Ground Pin
NC Not Connected
RESET Reset Pulse Output, Negative Pulse
Preliminary
MR
VDD Power Pin
Manual Reset Input, Pull Low to Reset, Internally Pulled High with 1µA Current Source
Function Block Diagram
Threshold Voltage Setting
VSET
VDD
CMP
POR
Power On Reset
MR
MR
Manual Re set
TIMER
VDD
P
RESET
N
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Preliminary
RT9811
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 MR 1mA
z Output Current, RESET 20mA
z Power Dissipation, P
@ TA = 25°C
D
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-25, 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
MR Minimum Pulse Width
MR to Reset Delay
I
DD
V
∆V
RD
t
RP
t
MR
t
MD
DD
TH
VDD = 1.5V ~ 5V, I
TA = 27°C
TA = 27°C
TH
VDD = 5V, Drop = -20mV
VDD = 1.5V, Drop = -20mV
VDD ≥ 1.02×V
Determined by t
TH
RP
OUT
= 0
0.9 -- 6 V
-- 2.5 --
-- Note1 -- V
-- -- 2 %
-- 25 --
-- 5 --
-- 400 -- mS
-- 400 -- mS
-- 0.8 --
MR Glitch Immunity -- 100 -- nS
MR Input Threshold
RESET Output Voltage
V
IH
V
IL
V
OH
V
OL
V
V
V
DD
DD
DD
= 3.3V
> VTH, I
< VTH, I
SOURCE
> 3.5mA
SINK
> 1mA
--
0.85V
DD
--
0.2V
DD
--
0.8V
DD
--
0.2V
DD
--
--
--
--
Note1: 1.5V ~ 5V, step 0.1V
µA
µS
µS
V
V
DS9811-00 June 2001 www.richtek-ic.com.tw
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RT9811
Package Information
Preliminary
D
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
B 1.397 1.803 0.055 0.071
Dimensions In Millimeters Dimensions In Inches
Min Max Min Max
H
L
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
www.richtek-ic.com.tw DS9811-00 June 2001
4
Preliminary
RT9811
DS9811-00 June 2001 www.richtek-ic.com.tw
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RT9811
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 DS9811-00 June 2001
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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