TCM1520A Datasheet, PDF (1/7 Pages) Texas Instruments – RING DETECTOR

TCM1520A
RING DETECTOR
SCTS005B – OCTOBER 1984 – REVISED DECEMBER 1990
• On-Chip 150-V Bridge Diode Configuration
• Reliable BIDFET^† Technology
• High Standby Impedance . . . 1 MΩ Typ
• Efficient High-Voltage Operation
• Output Compatible With TTL, NMOS, and
CMOS
• Built-In 5-V Series Regulator
• Built-In Lightning and Transient Protection
D OR P PACKAGE
(TOP VIEW)
AC INPUT 1
INVERTING OUTPUT 2
COMMON 3
5-V OUTPUT 4
8 AC INPUT
7 COMMON
6 C FILTER
5 BELL TAPPING SENSE
TCM1520A APPLICATION
description
The TCM1520A is a monolithic ring-detection
integrated circuit designed for use in isolated or
nonisolated telephone applications. The device
uses a modified form of the Texas Instruments
BIDFET^† technology to combine low-voltage
CMOS and high-voltage bipolar input/output
circuitry. It features efficient high-voltage (40 V to
150 V) operation with a typical current drain of
1 mA.
Phone Line
AC Ring
Signal
TCM1520A
Electronic Telephone
or Accessory
TTL /NMOS/CMOS
Microprocessor
During standby, the input impedance is
AVAILABLE OPTIONS
approximately 1 MΩ or greater, which prevents
PACKAGE
any interference with parallel off-hook telephones
transmitting DTMF or voice frequencies. The
TA
SMALL OUTLINE PLASTIC DIP
(D)‡
(P)
device achieves this high input impedance with an
on-chip series zener diode that does not conduct
until the voltage across AC INPUT (pins 1 and 8)
– 40°C to 85°C
TCM1520AD
TCM1520AP
‡ _{The D package is available taped and reeled with suffix R}
added to the device type (i.e., TCM1520ADR).
exceeds 8 V. When the voltage across pins 1 and
8 exceeds 18 V, the internal switch is closed, which bypasses the 6.8-V zener diode series resistor. This allows
more efficient power transfer to the load when the device is in the operating mode. In the operating mode, the
impedance of the device varies from 30 kΩ to 7 kΩ over the ring signal of 40 V at 16 Hz to 150 V at 68 Hz and
is reasonably independent of the output load.
In typical telephone applications, the TCM1520A is activated through the telephone line by a ring voltage of 40 V
at 16 Hz to 150 V at 68 Hz. The TCM1520A generates a signal suitable to drive an optocoupler or TTL, NMOS,
or CMOS logic. The 5-V OUTPUT can be used as a supply source for optocouplers or low-power logic. This
output is noninverting and is at a high level during ringing.
The TCM1520A incorporates lightning and transient protection that is designed to withstand lightning strikes
of 1.5-kV amplitude and 200-µs duration and also features built-in circuitry to avoid tapping or false triggering
due to transients.
Caution. These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive
foam during storage or handling to prevent electrostatic damage to the MOS gates.
† BIDFET – Bipolar, double-diffused, N-channel and P-channel MOS transistors on same chip. This is a patented process.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright © 1990, Texas Instruments Incorporated
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