Boost Converter. LR8425 Datasheet

LR8425 Converter. Datasheet pdf. Equivalent

Part LR8425
Description 500KHz Synchronous Boost Converter
Feature 5A, 500KHz Synchronous Boost Converter with Output Disconnect LESHAN RADIO COMPANY, LTD. LR8425 Ser.
Manufacture LRC
Datasheet
Download LR8425 Datasheet

5A, 500KHz Synchronous Boost Converter with Output Disconnec LR8425 Datasheet
Recommendation Recommendation Datasheet LR8425 Datasheet





LR8425
5A, 500KHz Synchronous Boost Converter
with Output Disconnect
LESHAN RADIO COMPANY, LTD.
LR8425 Series
„ INTRODUCTION:
The /58425 devices provide a power supply
solution for products powered by either a one-cell
Li-Ion or Li-polymer, or a two to three-cell
alkaline, NiCd or NiMH battery. The converter
generates a stable output voltage that is
adjusted by an external resistor divider. It
provides high efficient power conversion and is
capable of delivering output currents up to
1.5A at 5V at a supply voltage down to 2V.
The implemented boost converter is based on a
fixed switching frequency (500kHz typical),
current-mode controller using a synchronous
rectifier to obtain maximum efficiency. Boost
switch and rectifier switch are connected internally
to provide the lowest leakage inductance and best
EMI behavior possible. The current-mode control
scheme provides fast transient response and
good output voltage accuracy. At light load, the
converter will automatically enter into Pulse
Frequency Modulation (PFM) operation to reduce
the dominant switching losses. During PFM
operation, the IC consumes very low quiescent
current and maintains high efficiency over a wide
load current range.
The converter can be disabled to minimize battery
drain. During shutdown, the load is completely
disconnected from the battery.
The device allows use of small inductors and
output capacitors for USB devices.
„ FEATURES:
z 97% Efficiency at VOUT=5V from 3.3V Input
z Device Quiescent Current: 37μA (Typ)
z Guaranteed 2.5A Output Current at VOUT=5V
from 3.3V Input
z 500kHz PWM Switching Frequency
z Synchronous and Embedded Power
MOSFETs, No Schottky Diode Required
z Low RDS(ON) (main switch/synchronous switch)
at 5.0V output: 20/40mohm
z Input Voltage Range: 1.8V to 5.25V
z Adjustable Output Voltage Range:
from 2.5V to 5.5V
z Pulse Frequency Modulation Operation for
Improved Efficiency at Low Output Power
z Current Mode Operation with Internal
Compensation for Excellent Line and Load
Transient Response
z Logic Controlled Shutdown(<1μA)
z Load Disconnect During Shutdown
z Automatic output discharge at shutdown:
/58425A: Auto output discharge function
/58425B: No output discharge function
z Low Battery Comparator
z Internal Soft-Start to Limit Inrush Current
z Over Current Protection
z Input Under Voltage Lockout
z Output Over Voltage Protection
z Over-Temperature Protection
z Available in 2.1mm x 2.1mm QFN10 Package
„ APPLICATIONS˖
z All Single Cell Li or Dual Cell Battery
Operated Products as Tablet PC, Smartbook
and Other Portable Equipment
z Products including portable HDMI and USB-OTG
z USB Hosts Without Native 5V Supplies
z USB Charging Port (5V)
z Power Bank, Battery Backup Units
z Wireless Peripherals
z Portable Audio Players
z Personal Medical Devices
z Industrial Metering Equipments
z DC/DC Micro Modules
Ver0.5
1/7



LR8425
„ ORDER INFORMATION
Device No.
/58425AQD10
/58425BQD10
Output Voltage
Adjustable
Adjustable
LESHAN RADIO COMPANY, LTD.
Package
QFN2.1x2.1-10
QFN2.1x2.1-10
Packaging
3000 parts per reel
3000 parts per reel
„ PIN CONFIGURATION:
Top View
10 9 8
7
16
25
34
PIN
NO. NAME
1 CE
2 LBI
3 VIN
TYPE(1)
I
I
I
(QFN2.1X2.1-10)
DESCRIPTION
Chip Enable Input. Internal integrated with 1Mohm pull down resistor.
CE=High: Normal free running operation.
CE=Low: Shutdown; quiescent current <1μA. Output capacitor can be
completely discharged through the load or feedback resistors.
If CE is undefined, pin SW may ring.
Low Battery Comparator Input (comparator enabled with CE).
Battery Supply Input Voltage. The device gets its start-up bias from VIN.
Once AVOUT exceeds 2.3V, bias comes from AVOUT. Thus, once started,
operation is completely independent from VIN. Operation is only limited by
the output power level and the battery’s internal series resistance. The VIN
pin should be connected to the positive terminal of the battery and
bypassed with a low ESR ceramic bypass capacitor. Care should be taken
to minimize the loop area formed by the bypass capacitor connections,
the VIN pin, and the /58425 AGND pin. The minimum recommended
bypass capacitance is 1μF ceramic with a X5R or X7R dielectric and the
optimum placement is closest to the VIN pin and the AGND pin.
PCB trace length from VIN to the input filter capacitor(s) should be as short
and wide as possible.
Ver0.5
27





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