RT9718
Over Voltage Protection IC
General Description
The RT9718 is an integrated circuit optimized to protect
low voltage system from abnormal high input voltage (up
to 30V). The IC monitors the input voltage, battery voltage
and the charging current to make sure all three parameters
are operated in normal range. When the input voltage
exceeds a certain OVP threshold voltage level, the IC will
turn off the power MOSFET within 1μs to remove the power
before any damage occurs. The RT9718 also can provide
a voltage output without the existence of battery.
The current in the power MOSFET is also limited to prevent
charging the battery with an excessive current. The current
limit can be programmed by an external resistor between
ILIM and GND. The OCP function also has a 4-bit binary
counter that accumulates during an OCP event. When the
total count reaches consecutive 16 times, the power
MOSFET is turned off permanently unless the input power
is recycled.
The IC also monitors the battery voltage, Once the battery
voltage exceeds 4.35V and last for more then 180us
blinking time, the RT9718 will turn off the MOSFET. The
internal logic control will turn off the power MOSFET
permanently when the battery over-voltage event occurs
for consecutive 16 times.
Features
Fully Integrated Protection Function
½
½
½
Programmable OCP
Input OVP
Battery OVP
Withstand High Input Voltage Up to 30V
Over Voltage Turn Off Time Less Than 1us
High Accuracy Protection Thresholds
Over Temperature Protection
High Immunity of False Triggering Under Transients
Warning Indication Output
Enable Input
Thermal Enhanced WDFN Package
RoHS Compliant and Halogen Free
Applications
Cellular Phones
Digital Cameras
PDAs and Smart Phones
Portable Instruments
Pin Configurations
(TOP VIEW)
VIN
GND
NC
WRN
1
2
3
4
8
7
6
5
Ordering Information
RT9718
Package Type
QW : WDFN-8L 2x2 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
OVP
A : 6.80V
B : 5.85V
C : 6.25V
D : 7.20V
9
VOUT
ILIM
VB
EN
WDFN-8L 2x2
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
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.
www.richtek.com
1
DS9718-03 January 2019
GND
RT9718
Typical Application Circuit
RT9718
V
IN
C
IN
1µF
Chip Enable
5
EN
VB 6
7
ILIM
4
WRN
1 VIN
VOUT 8
C
OUT
1µF
Charger IC
(RT9502)
R
VB
200k
R
ILIM
25k
+
To System
2 GND
Battery
Functional Pin Description
Pin No.
1
2
3
4
5
6
7
8
Pin Name
VIN
GND
NC
WRN
EN
VB
ILIM
VOUT
Analog Ground.
No Internal Connection.
This is an open-drain logic output that turns LOW when any protection event occurs.
Chip Enable (Active Low). Pull this pin to low or leave it floating to enable the IC and
force it to high to disable the IC.
Battery voltage monitoring input. This pin is connected to the battery pack positive
terminal via an isolation resistor.
Over current protection threshold setting pin. Connect a resistor between this pin
and GND to set the OCP threshold.
Output through the power MOSFET.
The exposed pad must be soldered to a large PCB and connected to GND for
maximum thermal dissipation.
Pin Function
The input power source. The VIN can withstand up to 30V input.
9 (Expose Pad) GND
Function Block Diagram
VIN
VOUT
V
REF
I
bias
V
DD
INOVP
UVLO
EN
Logic
OTP
BASE
Driver
OCP
OCP
Seting
ILIM
Control
Logic
Buffer
BATOVP
VB
WRN
EN
GND
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2
DS9718-03 January 2019
RT9718
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage, V
IN
--------------------------------------------------------------------------------------------
−0.3V
to 30V
VOUT, VB ---------------------------------------------------------------------------------------------------------------
−0.3V
to 7V
Other Pins ---------------------------------------------------------------------------------------------------------------
−0.3V
to 6V
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-8L 2x2 ---------------------------------------------------------------------------------------------------------- 0.606W
Package Thermal Resistance (Note 2)
WDFN-8L 2x2,
θ
JA
----------------------------------------------------------------------------------------------------- 165°C/W
WDFN-8L 2x2,
θ
JC
---------------------------------------------------------------------------------------------------- 20°C/W
Junction Temperature ------------------------------------------------------------------------------------------------- 150°C
Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260°C
Storage Temperature Range ----------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV
MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
(Note 4)
Junction Temperature Range ----------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range ----------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
IN
= 5V, T
A
= 25°C, unless otherwise specified)
Parameter
Power On Reset
RT9718A
Operation Voltage
RT9718B
RT9718C
RT9718D
Supply Voltage POR
Threshold
Deglitch Time of POR
Symbol
Test Conditions
Min
Typ
Max
Unit
4
V
IN
4
4
4
V
POR
V
POR
Rising
V
UVLO
Falling
EN = 0V
EN = 5V
2.5
--
2.45
--
--
I
Q
I
SHDN
--
--
--
--
2.7
8
--
500
65
6.5
5.5
5.9
6.9
2.9
--
2.75
600
95
V
ms
V
A
V
Under Voltage Lockout Threshold V
UVLO
Input Quiescent Current
Input Shutdown Current
Protections
RT9718A
Input OVP
Threshold
Voltage
Input OVP Hysteresis
Input OVP Propagation Delay
Input OVP Recovery Delay
RT9718B
RT9718C
RT9718D
V
IN_OVP
6.6
5.6
6.05
7
--
V
OUT
= V
IN
x 80%
--
--
6.8
5.85
6.25
7.2
60
--
8
7
6
6.45
7.4
100
1
--
mV
s
ms
V
To be continued
DS9718-03 January 2019
www.richtek.com
3
RT9718
Parameter
Over Current Protection
Over Current Protection Blanking
Time
Over Current Recover Delay
Battery Over Voltage Protection
Battery OVP Falling Threshold
Battery OVP Blanking Time
Battery OVP Recover Delay
VB Pin Leakage Current
OTP Threshold
OTP Recover Delay
Soft-Start Time
Logic
EN Threshold Voltage
Logic-High V
IH
Logic-Low V
IL
Sink 5mA
1.5
--
100
--
--
--
--
200
0.35
--
--
0.4
400
0.8
1
V
V
k
V
A
T
SD
T
VBOV
V
VB
= 4.4V
Rising
Hysteresis
Symbol
I
OCP
T
OC
Test Conditions
As R
ILIM
= 25k
Min
0.93
--
--
Threshold Rising
VB
OVP
Hysteresis
4.3
--
4.225
--
--
--
--
--
--
--
Typ
1
180
64
4.35
30
--
180
8
--
140
20
8
8
Max
1.07
--
--
4.4
--
--
--
--
20
--
--
--
--
Unit
A
s
ms
V
mV
V
s
ms
nA
C
C
ms
ms
EN Internal Pull Down Resistor
WRN Output Logic Low
WRN Output Logic High Leakage
Current
Power MOSFET
On Resistance
R
ON
I
OUT
= 500mA, 4.3V < V
IN
< 6.5V
--
200
300
m
Note 1.
Stresses beyond those listed under
“
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 for extended periods may affect device reliability.
Note 2.
θ
JA
is measured in the natural convection at T
A
= 25°C on a low effective single layer thermal conductivity test board
of JEDEC 51-3 thermal measurement standard. The case position of
θ
JC
is on the exposed pad of the packages.
Note 3.
Devices are ESD sensitive. Handling precaution is recommended.
Note 4.
The device is not guaranteed to function outside its operating conditions.
www.richtek.com
4
DS9718-03 January 2019
RT9718
Typical Operating Characteristics
Input OVP vs. Temperature
6.80
6.78
1.10
OCP Threshold vs. Input Voltage
Input OVP (V)
6.76
6.74
6.72
6.70
6.68
OCP Threshold (A)
1.07
1.04
1.01
0.98
C
IN
= C
OUT
= 1μF
6.66
-50
-25
0
25
50
75
100
125
0.95
4.4
4.7
5
5.3
C
IN
= C
OUT
= 1μF, R
ILIM
= 25kΩ
5.6
5.9
6.2
6.5
6.8
Temperature (°C)
Input Voltage (V)
Battery OVP vs. Input Voltage
4.370
4.365
4.370
4.365
Battery OVP vs. Temperature
Battery OVP (V)
Battery OVP (V)
C
IN
= C
OUT
= 1μF
4.360
4.355
4.350
4.345
4.340
4.335
4.330
4.5
4.8
5.1
5.4
5.7
6
6.3
6.6
4.360
4.355
4.350
4.345
4.340
4.335
C
IN
= C
OUT
= 1μF, V
IN
= 5.5V
4.330
-50
-25
0
25
50
75
100
125
Input Voltage (V)
Temperature (°C)
Quiescent Current vs. Input Voltage
600
600
Quiescent Current vs. Temperature
Quiescent Current (µA)
1
500
400
300
200
100
Quiescent Current (µA)
500
400
300
200
100
C
IN
= C
OUT
= 1μF
0
2.8
3.45
4.1
4.75
5.4
6.05
6.7
0
-50
-25
0
25
C
IN
= C
OUT
= 1μF, V
IN
= 5.5V
50
75
100
125
Input Voltage (V)
Temperature (°C)
DS9718-03 January 2019
www.richtek.com
5
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