STT818B: PNP Bipolar Transistor
in Battery Power Management

STT818B Product Page

Looking at the rapid growth in handheld equipment, especially for the high volume GSM cellular phones, that represents the 75% worldwide handheld market, ST is in the position to cover this specific segment with all types of active components. Among these devices, the basic one necessary to supply the current when the battery needs to be charged, is the switching final device. ST proposes the most cost effective and practical solution with the new PNP transistor available, STT818B, with high gain and low voltage technology.

Description

Using the latest low voltage epitaxial planar technology based on interdigital layout, ST has introduced the new “High Gain” Power bipolar transistor family, with outstanding performance. Its very low saturation voltage combined with the “high gain” characteristics make it ideal for all high efficiency low voltage switching applications. The relevant circuit is simply the insertion of one small resistor between the transistor base and the battery management IC.

The STT818B PNP transistors are able to supply the 0.5A needed to charge the battery, with just 5mA base current. The Power Bipolar solution represents a cost effective alternative to the pair Super Logic level P-channel MOSFET and Schottly diode largely used for the same purpose. Features Cost effective solution; Very low saturation voltage; DC current gain >100 (hFE); 3A continuous collector current (IC); SOT23-6L package in tape & reel. Applications Power management in portable equipment.