Document Number: MC34673

Rev. 1.0, 01/2008

Freescale Semiconductor

Advance Information

*

This document contains certain information on a new product.

Specifications and information herein are subject to change without notice.

© Freescale Semiconductor, Inc., 2007-8. All rights reserved.

High Input Voltage 1.2A Charger

for Single-cell Li-Ion Batteries

The MC34673 is a cost-effective fully-integrated battery charger for

Li-Ion or Li-Polymer batteries. The high input voltage, up to 28V,

eliminates the input over-voltage protection circuit required in handheld

devices such as PDAs, cell phones, portable video game players and

digital still cameras.

A typical charge cycle includes trickle, constant-current (CC) and

constant-voltage (CV) charge modes. The CC-mode current is

programmable up to 1.2A with an external resistor. The voltage across

the external resistor is also used to monitor the actual charge current.

The constant voltage is fixed at 4.2V with 0.7% accuracy over a -20°C

to 70°C temperature range. The trickle-mode current is preset to 20%

of the CC-mode current when the battery voltage is lower than the

trickle-mode threshold. The end-of-charge (EOC) current threshold is

preset to 10% of the CC-mode current to save the board space and

cost. A charge current thermal foldback feature limits the charge

current when the IC internal temperature rises to a preset threshold.

The MC34673 also protects the system with its input over-voltage

protection (OVP) feature. In addition, the MC34673 has a 2.6V falling

power-on-reset (POR) threshold, making it perfect to work with current

limited power supplies. Three indication pins (PPR, CHG and FAST)

can be simply interfaced to a microprocessor or LEDs. When no power

supply is connected, or when disabled, the charger draws less than

1.0

µA leakage current from the battery.

Features

• No external MOSFET, reverse-blocking diode or current-sense resistor are required

• Guaranteed maximum 1.2A programmable CC-mode current

•

±0.7% voltage accuracy over -20°C to 70°C

•

±6% current accuracy over -40°C to 85°C

• 28V maximum voltage for the power input with 6.8V over-voltage protection threshold

• 2.6V minimum input operating voltage

• Trickle charge for fully discharged batteries

• Charge current monitor

• Charge current thermal foldback

• Pb-free packaging designated by suffix code EP

Figure 1. 34673 Simplified Application Diagram

POWER MANAGEMENT IC

EP SUFFIX (PB-FREE)

98ASA10774D

8-PIN UDFN

34673

ORDERING INFORMATION

Device

Temperature

Package

MC34673AEP/R2

-40°C to 85°C

8-UDFN

ON

OFF

VIN

GND

CHG

PPR

EN

BAT

ISET

FAST

TO BATTERY

TO MCU

34673