The LTC4009 supports Li-Ion/Polymer, NiMH, NiCd and sealed lead acid battery chemistries in multi-cell configurations. AC adapter current limiting maximizes the charge rate for a given fixed input power level, allowing the end product to operate at the same time the battery is charging without complex load management algorithms. The IC operates from input voltages up to 28V and is intended for applications including portable computers, portable instruments, and battery backup systems.
The LTC4009's synchronously rectified, buck switching topology drives all n-channel MOSFETs and enables efficiencies as high as 90% at 4A. Final float voltage accuracy is specified at ±0.5% and charge current is programmable with accuracy of ±4%. The LTC4009's quasi-constant frequency PWM architecture guarantees no audible noise operation and minimizes filtering needs, while the high operating frequency of 550kHz allows the use of small inductors and capacitors.
| Summary of Features: LTC4009 | |
 | High Efficiency PWM Switchmode Battery Charger Controller |
| Multiple Battery Chemistries & Multi-Cell Configurations Supported: |
| •Li-Ion/Polymer, NiMH, NiCd, SLA | |
| Charge Current up to 4A |
| 550kHz Switching Frequency Enables Small External Components |
| ±0.5% Output Float Voltage Accuracy |
| Programmable Charge Current: ±4% Accuracy |
| No Audible Noise with Ceramic Capacitors |
| Synchronous Rectification: High Efficiency up to 92% @ 2A |
| Enhanced Non-Overlap Control of External Power FETs |
| Wide Input Supply Voltage Range: 6V to 28V |
| Wide Output Battery Voltage Range: 3V to 28V |
| Indicator Outputs for AC Adapter Present, Charging, C/10 Current Detection and Input Current Limiting |
| Analog Charge Current Monitor |
| Micropower Shutdown |
| Compact, Low-Profile (0.75mm) 4mm x 4mm QFN-20 Package |
