PSB2121 Datasheet | Siemens Semiconductor Group

General-Purpose Power Controller (GPPC) PSB 2121 CMOS IC Features q Switched mode DC/DC-converter q CCITT ISDN patible q Low power dissipation q Supply voltage range 8 to 70 V q Programmable input undervoltage protection q Programmable overcurrent protection q Soft start q Power housekeeping input q Oscillator synchronization input/output q High voltage CMOS-technology 70 V P-DSO-20-1 P-DIP-16 Type PSB 2121-P PSB 2121-T Version V A4/A5 V A4/A5 Ordering Code Q67100-H8646 Q67100-H6032 Package P-DIP-16 P-DSO-20-1 (SMD) The PSB 2121 is a pulse width modulator circuit designed for fixed-frequency switching regulators with very low power consumption. In telephony and ISDN systems a high conversion yield is crucial to maintain functionality in all supply conditions via “S” or “U” interfaces. The PSB 2121 design and technology realize high conversion efficiency and low power dissipation. It should be recognized that the PSB 2121 can also be used in numerous DC/DC-conversion systems other than ISDN-power supplies. Semiconductor Group PSB 2121 The PSB 2121 Contains the Following Functional Blocks q Undervoltage lockout q Temperature pensated voltage reference q Sawtooth oscillator q Error amplifier q Pulse width modulator q Digital current limiting q Soft start q Double pulse inhibit q Power driver Together with few external ponents it provides a stable 5 V DC-supply for subscriber terminals (TEs) or network terminations (NTs). It can also be programmed for higher output voltages, e.g. to supply S-lines with 40 V. Pin Configurations (top view) P-DSO-20 P-DIP-16 Semiconductor Group PSB 2121 Pin Definitions and Functions Pin No. Pin No. Symbol Input (I) P-DSO P-DIP Output (O) 1 2 4 5 6 1 2 3 4 5 Definition Reference voltage Positive current sense Negative current sense Ground Gate Function Output of the 4.0 V reference voltage. When the voltage difference between these two pins exceeds 100 m V, the digital current limiting bees...