RT9709 Datasheet, PDF (1/12 Pages) Richtek Technology Corporation – Integrated Over Voltage Protection Circuit

RT9709
Integrated Over Voltage Protection Circuit
General Description
The RT9709 is an integrated circuit (IC) optimized to protect
low voltage system from abnormal high voltage input up to
28V. The IC monitors the input voltage, battery voltage
and the charging current to make sure all three parameters
are operated in normal range. It also monitors its own
temperature and turns the MOSFET off when the chip
temperature exceeds 140°C.
The RT9709 can support AC charger or USB charger. When
the input voltage exceeds the OVP threshold, the IC turns
off the MOSFET within 1us to remove the power before
any damage occurs.
The current in the 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 has a 4-bit binary counter
that accumulates during an OCP event. When the total
count reaches 16 times, the MOSFET will be turned off
permanently unless the input power is recycled.
The IC also monitors the battery voltage VB. When the
battery voltage exceeds 4.4V and last for more than 180us
the RT9709 will turn off the MOSFET. The internal logic
control will turn off and latch the MOSFET when the battery
over-voltage event reaches 16 times.
Pin Configurations
(TOP VIEW)
VIN 1
VIN 2
GND 3
WRN 4
NC 5
NC 6
GND
13
12 NC
11 VOUT
10 VOUT
9 ILIM
8 VB
7 EN
WDFN-12L 4x3
VIN 1
VIN 2
GND 3
WRN ⁴
NC 5
GND
11
10 VOUT
9 VOUT
8 ILIM
7 VB
EN
WDFN-10L 3x3
Features
z Fully Integrated Protection Circuit for Three
Protection Variables
` User Programmable OCP Threshold
` Input OVP Less than 1us
` Battery OVP
z Up to 30V Over Voltage Protection
z High Accuracy Protection Threshold
z High Immunity of False Triggering Under Transients
z Warning Indication Output
z Enable Input
z Thermally Enhanced WDFN Package
z RoHS Compliant and Halogen Free
Applications
z Cellular Phones
z Digital Cameras
z PDAs and Smart Phones
z Portable Instruments
Ordering Information
RT9709
Note :
Package Type
QW : WDFN-12L 4x3 (W-Type)
QWB : WDFN-10L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
OVP
Default : 6.8V
A : 5.85V
B : 6.25V
Richtek products are :
` 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.
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
DS9709-02 April 2011
www.richtek.com
1