RT9945 Datasheet, PDF (1/33 Pages) Richtek Technology Corporation – Power Management ICs for Handheld Device

RT9945
Power Management ICs for Handheld Device
General Description
The RT9945 is a complete power management IC (PMIC)
for handheld device platform. This PMIC contains a fully
integrated linear charger for a single cell Lithium Ion battery,
five LDO linear regulators and two high efficiency buck
converters, a comparator, a reset and an I²C serial interface
to program one buck and one regulator output voltages as
well as power on timing control for complete flexibility.
The linear charger integrates LDO, MOSFET pass element,
and thermal-regulation circuitry. The proprietary thermal-
regulation circuitry limits the die temperature when fast
charging or while exposed to high ambient temperatures,
allowing maximum charging current without damaging the
IC.
The two step-down converters are optimized for small size
inductor and high efficiency applications. They utilize a
proprietary hysteretic PWM control scheme that switches
with nearly fixed frequency and is adjustable, allowing the
customer to trade some efficiency for smaller external
component, as desired. The output current is guaranteed
up to 600mA, while quiescent current is a low 40μA (typ).
The LDO linear regulators provide high power supply
rejection rate and have only 45uV_RMS of output noises for
100Hz to 10kHz frequency range to power noise sensitive
RF sections.
The RT9945 is available in WQFN-40L 5x5 package.
Ordering Information
RT9945
Note :
Package Type
QW : WQFN-40L 5x5 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
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.
Features
z Charger
` Adapter/USB & Battery Two Input with Auto Power
Dynamic Path.
` PWR_IN LDO Support Continuous 1.5A, Peak 2A
Current
` 4.5V to 5.5V Operation Voltage Range with Max.
18V Input Voltage
` Switch Well for LDO and Charger Power MOSFET
` Set Charge Current by ISETA Pin
` Charge Status Indicator
` Interrupt for PWR_IN Plug In/Out, Time Out and
Charger Done.
` Battery Temperature Monitoring
z Hysteretic Buck
` Buck 1 for Memory, Adjustable Voltage and 600mA
Output Current
` Buck 2 for Core voltage with 25mV/step I²C
Adjustable, 600mA Output Current
` Max. Efficiency Up to 90%
z LDO
` LDO1 : 3.3V/500mA for I/O, Default ON
` LDO2 : 1.2V/80mA for PLL, Default ON
` LDO3 : 1.2V/80mA for VDD Alive.
` LDO4 : 2.5V/50mA, Default OFF
` LDO5 : 3.3V/50mA, Default OFF
` Minimize the External Component Counts
z Other
` Low Voltage Detector
` I<sup>2</sup>C Compatible Interface
` Power ON Timing Control
z RoHS Compliant and Halogen Free
Applications
z GPS and PND
z PDA and Smart Phones
z Handheld Devices
DS9945-01 April 2011
www.richtek.com
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