®
RT9553A
High Accuracy Current/Voltage Sensing and Protection IC
General Description
The RT9553A is designed for over-current detection and
over-/under-voltage protection.
It provides users to set over-current threshold by the ILIM
pin to compare that senses dropping voltage between CSP
pin and CSN pin. Moreover, users can set over-/under-
voltage threshold by the OVSET pin/UVSET pin to
compare with the CSP voltage. The RT9553A is a available
in the WDFN-10L 3x3 package.
Features
Common Mode Input Range up to 24V
VCC Operating Current : 200μA
μ
VCC Shutdown Current : 10μA (under S3/S4/S5)
μ
Programmable Over-Current Level
One Shot PROCHOT Signal when OCP
Pull Low RESET Signal when OVP/UVP
OVP/UVP with 8% Recover Hysteresis Range
Programmable OVP/UVP De-glitch Time
Ordering Information
RT9553A
Package Type
QW : WDFN-10L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
½
Applications
Notebook
Pin Configurations
(TOP VIEW)
CSP
VCC
ILIM
EN
TIMER
1
2
3
4
5
10
9
8
7
6
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
11
CSN
PROCHOT
RESET
OVSET
UVSET
½
WDFN-10L 3x3
Marking Information
3U= : Product Code
3U=YM
DNN
YMDNN : Date Code
Simplified Application Circuit
R
SENSE
Input
I
SENSE
RT9553A
CSN
CSP
VCC
Enable
EN
ILIM
PROCHOT
RESET
OVSET
UVSET
TIMER
Output
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9553A-00
September 2014
GND
www.richtek.com
1
RT9553A
Functional Pin Description
Pin No.
1
2
3
4
5
6
7
8
9
10
11 (Exposed Pad)
Pin Name
CSP
VCC
ILIM
EN
TIMER
UVSET
OVSET
RESET
PROCHOT
CSN
GND
Positive Current Sense Input.
Power Supply Input. Connect this pin to 5V and place a minimum 0.1F
decoupling capacitor. The decoupling capacitor should be placed to this pin
as close as possible.
Over-Current Trip Point Setting Input. The setting range is from 0.4V to 2V.
Enable Control Input.
Deglitch Time Setting of OV/UV Protection. Connect a resistor from this pin
tied to GND to set deglitch time. Do not parallel any filter capacitor to this pin.
Under-Voltage Trip Point Setting Input. The setting range is from 0.55V to 3V.
Over-Voltage Trip Point Setting Input. The setting range is from 0.55V to 3V.
Open-Drain Output. Connect to an external resistor to pull high. When OV/UV
occurs, this pin will be pulled low.
Open-Drain Output. Connect to an external resistor to pull high. When OC
occurs, this pin will be pulled low.
Negative Current Sense Input.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Pin Function
Function Block Diagram
EN
VCC
CSP
CSN
Current Sensing
Amplifier
+
-
VRON
POR
ILIM
R1
OVSET
OC_Comparator
+
One Shot
-
PROCHOT
OV_Comparator
-
+
RESET
Deglitch
Latch
GND
UV_Comparator
-
UVSET
R2
+
TIMER
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9553A-00
September 2014
RT9553A
Operation
The RT9553A consists of a current sensing amplifier, and
two comparators, and it provides the following functions :
over-current protection, over-voltage protection and under-
voltage protection.
Over-Current Protection
With mΩ order of resistor shunts between CSP and CSN,
the current sensing amplifier multiplies the voltage between
CSP and CSN by 20 and compares the result with the
ILIM voltage. If the output voltage of current sensing
amplifier is larger than the ILIM voltage, the PROCHOT
voltage is pulled low.
OVP/UVP Deglitch Time
The output signal of OV_comoparator or UV_comparator
is delayed by deglitch timer. The delayed time is decided
by the resistor (see spec.) connected to the TIMER pin.
Over-/Under-Voltage Protection
The OVSET voltage is set by users and it compares with
the voltage which is 1/9 of CSP voltage with
OV_comparator. The UVSET voltage is set by users and
it also compares with the voltage which is 1/9 of CSP
voltage with UV_comparator. Either the output of
OV_comoparator or UV_comparator is high, the RESET
voltage is pulled low.
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9553A-00
September 2014
www.richtek.com
3
RT9553A
Absolute Maximum Ratings
(Note 1)
CSP/CSN to GND ---------------------------------------------------------------------------------------------------------
−0.3V
to 28V
VCC, ILIM, EN, UVSET, OVSET, RESET, PROCHOT to GND -------------------------------------------------
−0.3V
to 6V
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-10L 3x3 ------------------------------------------------------------------------------------------------------------- 3.27W
Package Thermal Resistance (Note 2)
WDFN-10L 3x3,
θ
JA
------------------------------------------------------------------------------------------------------- 30.5°C/W
WDFN-10L 3x3,
θ
JC
------------------------------------------------------------------------------------------------------- 7.5°C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Model) ----------------------------------------------------------------------------------------------------- 200V
(Note 4)
Recommended Operating Conditions
High-Side Voltage, VCSP/VCSN -------------------------------------------------------------------------------------- 5V to 24V
Supply Voltage, VCC ----------------------------------------------------------------------------------------------------- 4.5V to 5.5V
Junction Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
CC
= 5V, T
A
= 25°C, unless otherwise specified)
Parameter
CSN CSP Input
Input Voltage Range
I
CSN
+ I
CSP
VCC Input
VCC Operating Current
VCC Shutdown Current
VCC POR Rising Voltage
Enable
Enable Input
Voltage
Logic-High
Logic-Low
Symbol
V
CSP
, V
CSN
Test Conditions
Min
5
Typ
--
50
--
200
--
--
400
--
--
50
--
--
Max
24
--
5
--
10
3.7
--
--
0.3
--
18
10
Unit
V
A
VCC = 5V, EN High
VCC = 5V, EN Low
I
VCC
I
VCC_shd
V
IN_POR
Rising
Hysteresis
--
--
--
--
2.8
--
0.7
--
--
A
A
V
mV
V
IH
V
IL
V
Over Current Protection
System Response Time
Open-Drain Output
Duration
Open-Drain Output Ron
T
PROCHOT
R
on_PROCHOT
s
ms
10
--
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9553A-00
September 2014
RT9553A
Parameter
Input Current Sensing
Accuracy
PROCHOT Leakage
Current
ILIM Leakage Current
ILIM Operation Range
Symbol
OC
acc
I
leak_PROCHOT
I
leak_ILIM
V
ILIM
OVP
acc
V
OVSET
= 0.55V to 3V
V
OVSET
= 0.55V to 3V
UVP
acc
V
UVSET
= 0.55V to 3V
V
UVSET
= 0.55V to 3V
R
on_RESET
I
leak_RESET
T
Timer
I
Sink
= 10mA
EN Low
R
Timer
= 375k
R
Timer
= 125k
Test Conditions
V
ILIM
= 0.4V to 2V
EN Low
EN Low
Min
--
--
--
0.4
Typ
--
--
--
--
Max
5
5
5
2
Unit
%
A
A
V
Over-/Under-Voltage Protection
OVP Accuracy
OVP Recover Hysteresis
Range
UVP Accuracy
UVP Recover Hysteresis
Range
Open Drain Output Ron
RESET Leakage Current
OVP/UVP De-glitch Time
--
--
--
--
--
--
--
--
--
8
--
8
--
--
15
5
5
--
5
--
10
5
--
--
%
%
%
%
A
s
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 high effective thermal conductivity four-layer test board per JEDEC 51-7.
θ
JC
is
measured at the exposed pad of the package.
Note 3.
Devices are ESD sensitive. Handling precaution is recommended.
Note 4.
The device is not guaranteed to function outside its operating conditions.
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9553A-00
September 2014
www.richtek.com
5
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