POWER MANAGEMENT



www.semtech.com

Miniature Integrated High Current

Lithium-Ion Battery Charger

SC805A

POWER MANAGEMENT

Description

Style Name _GreenBarText

Features

Applications

Fully integrated charger with FET pass transistor,

Reverse-blocking diode, sense resistor and thermal

protection

High accuracy charge current*

Tiny 3mm x 3mm 0-lead MLPD package

Programmable pre-charge, fast-charge and

termination current

Battery voltage controlled to % accuracy

Built-in timer for protection and complete charging

NTC interface with battery detection

Soft-start to reduce adapter in-rush current

Up to A continuous charge current

Input voltage range from 3V to 6V allows seamless

charging from current limited adapter

Provides adapter voltage VCCIL to power external

accessories

Battery present detection and output indicator

Operates in charger or LDO-Mode without battery

0.µA battery drain current in shutdown and monitor

modes

Over-current protection in all charging modes

CHRGB output communicates charging and

end-of-charge cycle

*US Patent 6,836,095

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The SC805A is a fully integrated, single cell, constant-

current (CC)/constant-voltage (CV) Lithium-Ion battery

charger in a tiny 3x3 mm thermally enhanced lead-free

MLP package. The SC805A can operate as a stand-alone

charger or in conjunction with a Power Management Inte-

grated Circuit (PMIC).

The SC805A has a pre-charge function for trickle charging

deeply discharged batteries. The fast-charge current is

enabled automatically when the battery voltage reaches

the required threshold. When the battery reaches the

constant voltage or CV portion of the charge curve, the

SC805A switches to CV regulation mode. In this mode

the output current decays as the battery charges until the

termination current is reached and the SC805A signals the

charge cycle is complete. The SC805A can be configured

to continue charging for a pre-determined time before

turning off, or to turn off immediately upon termination.

After turning off its output, the SC805A enters monitor

mode. If the battery voltage drops by 00mV from the

CV voltage a new charge cycle will begin. The timer

function also protects against charging faulty batteries by

turning off if the pre-charge time exceeds ¼ of the total

programmed charge duration.

The SC805A also provides battery detection, and a battery

NTC thermistor interface to disable charging when the

battery temperature exceeds safe-to-charge limits.

TheSC805A canalsofunctionasageneralpurposecurrent

source or as a current source for charging nickel-cadmium

(NiCd) and nickel-metal-hydride (NiMH) batteries.

C1

1µF

BATTERY

R7

1k

SC805A

1

7

9

4

5

10

2

8

3

6

VCC

EN/NTC

RTIME

IPRGM

ITERM

CHRGB

VCCIL

NOBAT

VOUT

GND

R4

3.01k

RT1

Thermistor

D2

LED

C1

2.2µF

Charging

Indicator

D3

LED

R5

3.01k

R2

3.01k

R1

3.01k

SC805A Typical Application Circuit

D1

LED

CHARGER VIN

R3

39.2k

Adapter

Present

Indicator

Charge

Complete

Indicator

R6

1k

Features

Applications

Typical Application Circuit

Description

Cellular Phones

PDAs

Handheld Meters

Charging Stations

USB Chargers

Digital Cameras

Programmable Current Source

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March 3, 2007