®
RT9818
Micro-Power Voltage Detectors
General Description
The RT9818 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 1.2V to 5V, which
covers most digital applications. It features low supply
current of 3μA. The RT9818 performs supervisory function
by sending out a reset signal whenever the V
DD
voltage
falls below a preset threshold level. This reset signal will
last the whole period before V
DD
recovering. Once V
DD
recovered upcrossing the threshold level, the reset signal
will be released after a
certain delay time. RT9818 is
provided in SC-82, SC-70-3, SOT-23-3, SOT-23-5 and
SOT-89 packages.
Features
Internally Fixed Threshold 1.2V to 5V in 0.1V Step
High Accuracy
±
1.5%
Low Supply Current 3μA
μ
No External Components Required
Quick Reset within 20μs
μ
Built-In Recovery Delay Include 0ms, 55ms, 220ms,
450ms Options
Low Functional Supply Voltage 0.9V
N-Channel Open-Drain Output
Small SC-82, SC-70-3, SOT-23-3, SOT-23-5, SOT-89
Packages
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Ordering Information
RT9818
-
Package Type
U3 : SC-70-3
V : SOT-23-3
VL : SOT-23-3 (L-Type)
B : SOT-23-5
X : SOT-89
Y : SC-82
YR : SC-82 (R-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Threshold Voltage
12 : 1.2V
13 : 1.3V
:
49 : 4.9V
50 : 5.0V
Reset Active Timeout Period
A = 0ms
(RESET)
B = 55ms
(RESET)
C = 220ms
(RESET)
D = 450ms
(RESET)
E = 0ms
(RESET)
F = 55ms
(RESET)
G = 220ms
(RESET)
H = 450ms
(RESET)
Computers
Controllers
Intelligent Instruments
Critical
μP
and
μC
Power Monitoring
Portable/Battery-Powered Equipment
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Typical Application Circuit
100k
Pull Up
VDD
P
RESET/
RESET
RT9818
GND
VDD
RESET/
RESET
Note :
½
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
½
Suitable for use in SnPb or Pb-free soldering processes.
is a registered trademark of Richtek Technology Corporation.
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
DS9818-11 August 2016
www.richtek.com
1
RT9818
Pin Configuration
(TOP VIEW)
GND
4
NC
3
2
RESET/
RESET
4
VDD
NC
3
3
2
RESET/
RESET
VDD
2
VDD
GND
GND
RESET/
RESET
SC-82
VDD
3
2
SC-82 (R-Type)
VDD
3
2
SC-70-3
NC
4
2
3
NC
5
1
2
3
RESET/
RESET
GND
GND
RESET/
RESET
RESET/ VDD GND
RESET
RESET/ VDD
RESET
GND
SOT-23-3
SOT-23-3 (L-Type)
SOT-23-5
SOT-89
Functional Pin Description
Pin Name
GND
RESET
RESET
VDD
Ground.
Active low open-drain reset output.
Active high open-drain reset output.
Power pin.
Pin Function
Functional Block Diagram
VDD
RESET/
RESET
VSET
Threshold
Voltage Setting
CMP
Timer
N MOS
GND
POR
Power On Reset
Timing Diagram
V
DD
V
TH
0V
V
RESET
Delay Time (0, 55, 220, 450ms)
0V
V
RESET
Delay Time (0, 55, 220, 450ms)
0V
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9818-11 August 2016
RT9818
Absolute Maximum Ratings
(Note 1)
−0.3V
to 6V
−0.3V
to 6V
20mA
0.25W
0.4W
Terminal Voltage (with Respect to GND)
V
DD
-----------------------------------------------------------------------------------------------------------------------------
All Other Inputs -------------------------------------------------------------------------------------------------------------
Input Current, I
VDD
----------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
SC-70 / SC-82 ---------------------------------------------------------------------------------------------------------------
SOT-23-3 ---------------------------------------------------------------------------------------------------------------------
SOT-23-5 --------------------------------------------------------------------------------------------------------------------- 0.4W
SOT-89 ------------------------------------------------------------------------------------------------------------------------ 0.55W
Package Thermal Resistance (Note 2)
SC-70 / SC-82,
θ
JA
--------------------------------------------------------------------------------------------------------- 400°C/W
SOT-23-3,
θ
JA
---------------------------------------------------------------------------------------------------------------- 250°C/W
SOT-23-5,
θ
JA
---------------------------------------------------------------------------------------------------------------- 250°C/W
SOT-89,
θ
JA
------------------------------------------------------------------------------------------------------------------ 180°C/W
Lead Temperature (Soldering, 10sec.) --------------------------------------------------------------------------------- 260°C
Storage Temperature Range ---------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ----------------------------------------------------------------------------------------------- 2kV
(Note 4)
Recommended Operating Conditions
Junction Temperature Range ---------------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range ---------------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
DD
= 3V, unless otherwise specified)
Parameter
Operating V
DD
(V
OUT
) Range
Supply Current
Reset Threshold
Threshold Voltage Accuracy
V
DD
Drop to Reset Delay
RT9818A/E
Reset Active
Time Out Period
RT9818B/F
RT9818C/G
Symbol
V
DD
I
DD
V
TH
V
TH
t
RD
Test Conditions
V
TH
= 3V, V
DD
= 4.5V, T
A
= 27C
T
A
= 27C
T
A
= 27C
Drop = V
TH
125mV
Min
0.9
--
--
1.5
--
--
35
143
292
--
--
Typ
--
3
1.2 to 5
--
20
0
55
220
450
--
Max
6
8
--
1.5
--
--
75
297
608
0.4
Unit
V
A
V
%
s
t
RP
V
DD
1.02 x V
TH
ms
RT9818D/H
RESET Output Voltage Low
V
OL
(Note 5)
Hysteresis Width
V
HYS
3 = V
DD
< V
TH
I
SINK
> 3.5mA
V
V
0.01V
TH
0.016V
TH
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9818-11 August 2016
www.richtek.com
3
RT9818
Note 1.
Stresses beyond those listed
“Absolute
Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2.
θ
JA
is measured at T
A
= 25°C on a low effective thermal conductivity single-layer test board per JEDEC 51-3.
Note 3.
Devices are ESD sensitive. Handling precaution is recommended.
Note 4.
The device is not guaranteed to function outside its operating conditions.
Note 5.
The voltage V
OL
can be calculated by V
OL
= V
DD
−
Ir * R. Where R is the pull-up resistor and Ir is the current flowing
through the pull-up resistor. For typical application (R=100kΩ), V
OL
is less than 0.2V.
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9818-11 August 2016
RT9818
Typical Operating Characteristics
Nch Driver Output Current vs. V
DS
2.4
Nch Driver Output Current vs. V
DS
60
50
RT9818A-12
V
DD
= 1.1V
RT9818C-30
V
DD
= 2.8V
V
DD
= 2.5V
Output Current (mA)
2.0
1.6
1.2
0.8
0.4
0.0
0
0.3
0.6
0.9
Output Current (mA)
40
30
20
10
0
V
DD
= 1V
V
DD
= 2V
V
DD
= 1.5V
1.2
1.5
0
0.5
1
1.5
2
2.5
3
3.5
V
DS
(V)
V
DS
(V)
Nch Driver Output Current vs. V
DS
120
Output Voltage vs. Input Voltage
7
RT9818A-45
100
RT9818
6
Output Current (mA)
Output Voltage (V)
80
60
40
20
0
0
1
2
3
4
5
5
4
3
2
1
0
0
1
2
3
4
5
6
V
DD
= 4.4V
= 4V
= 3.5V
= 3V
= 2.5V
= 2V
= 1.5V
4.5V
1.2V
V
DS
(V)
Input Voltage (V)
Supply Current vs. Input Voltage
6
5
Supply Current vs. Input Voltage
4.0
RT9818A-12
80°C
RT9818C-30
3.5
Supply Current (μA)
Supply Current (μA)
3.0
2.5
80°C
4
25°C
3
2
1
0
0
1
2
3
4
5
6
25°C
2.0
1.5
1.0
0.5
0.0
0
1
2
3
4
5
6
−30°C
−30°C
Input Voltage (V)
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
Input Voltage (V)
is a registered trademark of Richtek Technology Corporation.
DS9818-11 August 2016
www.richtek.com
5
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