TCM1501B, TCM1506B, TCM1512BTCM1531, TCM1532, TCM1536, TCM1539TELEPHONE TONE-RINGER DRIVERS

SCTS020 - MARCH 1986 - REVISED APRIL 1987

features

• Electronic Replacement for Electromechanical Telephone Bell When Used With Transducer
• Designed to Meet or Exceed FCC Part 68 Class B Ringer Requirements
• Low-Cost External Component Requirements
• Low External Component Count
• High Standby Input Impedance 1 M Typ
• Low Ringer Equivalency Number < 1 Typ
• Single-Ended High-Voltage Output Compatible With Piezo Transducer or Transformer-Coupled Speaker
• Reliable BIDFET Process Technology Provides Efficient High-Voltage Operation
• On-Chip High-Voltage Full-Wave Diode Bridge Rectifier and Output Voltage Regulator
• On-Chip Circuitry Provides Ring Rejection of Rotary Dial Transients, Lightning, and Induced High-Voltage Transients
• On-Chip Thyristor Coupled With Additional External Components Provides Enhanced Rejection of Dial Pulses
• TCM1501B, TCM1512B, and TCM1506B Are Improved Direct Replacements for TCM1501A, TCM1512A, and TCM1506A, Respectively
• Requires Only a Single-Value Oscillator Resistor (Eliminates Binning Codes of the TCM15xxA Series)

description

The TCM1501B, TCM1506B, TCM1512B, TCM1531, TCM1532, TCM1536, and TCM1539 are monolithic integrated circuit telephone tone-ringer drivers that, when coupled with an appropriate transducer, replace the electromechanical bell. These devices are designed using BIDFET technology for use with either a Piezo transducer or an inexpensive transformer-coupled speaker to produce a pleasing tone composed of a high frequency (f_H) alternating with a low frequency (f_L) resulting in a warble tone. Each device is powered and activated by the telephone line ring voltage, which may vary from 40 Vrms to 150 Vrms at frequencies from 15.3 Hz to 68 Hz.

During low-voltage (off-hook) standby, typical input impedance is greater than 1 M; this prevents interference with telephone DTMF or voice signals without the use of expensive mechanical switches. This high standby impedance is achieved with an on-chip series zener diode that is activated by a differential input voltage of typically 8.9 V at AC INPUT (pins 1 and 8). A voltage level of typically 17 V differential at AC INPUT deactivates the internal zener diode, allowing for more efficient power transfer to the load when the device is in the operating mode. During ringing, the impedance of the applied circuit (see Figures 4, 5, and 6) varies from 30 k to 8 k over the Class B ring signal and is reasonably independent of the output load.

These devices feature lightning and transient protection circuitry designed to withstand transients of 1.5 kV for up to 200 ms duration when used with the proper external circuitry (see Figures 4 and 5). In addition, an on-chip thyristor coupled with an external resistor and capacitor circuit reject dial pulses from parallel telephones so that false ringing (tapping) does not occur (see application information section).

The TCM1501B, TCM1506B, TCM1521B have a provision for bypassing the internal series diode with one of lower voltage, thereby lowering the turn-on threshold of the devices. If the antitapping thyristor is used with these devices, an external zener diode must be added in series with ANTITAPPING OUT/INTERNAL ZENER BYPASS.

These telephone tone-ringer drivers may be used in nontelephone communications applications. For example, the devices can be used with a few external components to produce an inexpensive and highly efficient alarm (see Figure 6).

View more information about generic part numbers:TCM1531, TCM1532, TCM1536

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