The document is an application note about LT1505 1505fc battery charger. Its features include simple charging method, wide range of rechargeable batteries, high charging voltage accuracy, programmable charging current by resistor or DAC, and switching frequency up to 280kHz.
The LT1505 is a constant‑current/constant‑voltage battery charger controller designed for fast charging of Li‑Ion, NiMH, NiCd and lead‑acid rechargeable batteries. It offers very high efficiency (up to 97 %), a low 0.5 V dropout voltage and programmable charging current via external resistors or a DAC. The device can be synchronized up to 280 kHz and includes a flag output to indicate charge completion.
Electrical characteristics include a supply current of 12‑15 mA, switching frequencies of 180‑220 kHz, and operation over a 0 °C to 70 °C ambient temperature range. Detailed pin functions, block diagram, and layout recommendations are provided for designers to implement the charger in notebook computers, portable instruments and other applications.
| Efficiency | Up to 97 % |
|---|---|
| Dropout Voltage | 0.5 V |
| Switching Frequency | 180 kHz – 220 kHz |
| Supply Current | 12 mA – 15 mA |
| Ambient Temperature Range | 0 °C to 70 °C |
The charging current can be set by external resistors or by a DAC.
Pulling the SHDN pin below 1 V stops switching and shuts down the charger.