MC34673AEPR2

The MC34673 is a high-input-voltage 1.2A charger for single-cell Li-Ion batteries — a cost-effective, fully integrated Li-Ion/Li-Polymer battery charger. Its input voltage of up to 28V eliminates the need for input OVP circuits in handheld devices. A typical charge cycle includes trickle, constant current (CC), and constant voltage (CV) modes. The CC mode current is programmable up to 1.2A via an external resistor, and the voltage across the external resistor can be used to monitor the actual charge current. The CV is fixed at 4.2V with 0.7% accuracy over a 0°C to 70°C temperature range. When the battery voltage falls below the trickle mode threshold, the trickle mode current is preset to 20% of the CC mode current. The end-of-charge (EOC) current threshold is preset to 10% of the CC mode current, saving board space and cost. When the IC junction temperature rises to a preset threshold, the thermal foldback function limits the charge current. The MC34673 also features input OVP to protect the system. In addition, the MC34673 has a 2.6V falling-edge power-on reset (POR) threshold, making it suitable for use with current-limited power supplies. Three indicator pins (PPR, CHG, and FAST) can be connected directly to a microprocessor or LEDs. When the power supply is disconnected or disabled, the leakage current drawn from the battery is less than 1.0μA. The MC34673 is available in an 8-pin UDFN package; the EP suffix denotes a lead-free package.

Applications

• Handheld devices
• PDA
• Mobile phones
• Portable handheld game consoles
• Digital cameras

Key features

• No external MOSFET, reverse blocking diode, or current sense resistor required
• Guaranteed maximum 1.2A programmable constant-current mode charging current
• Voltage accuracy ±0.7% over 0℃ to 70℃
• Current accuracy ±6% over -40℃ to 85℃
• Maximum power supply input voltage 28V, overvoltage protection threshold 6.8V
• Minimum input operating voltage 2.6V
• Trickle charging support for fully discharged batteries
• Charge current monitoring support
• Charge current thermal foldback
• EP suffix: lead-free package