MC145745

MOTOROLA SEMICONDUCTOR TECHNICAL DATA Order this document by MC145745/D MC145745 Product Preview V.21/V.23 Telemeter Modem The MC145745 is a selectable modem chip compatible with ITU V.21 (300 baud full duplex asynchronous) and V.23 mode 2 (1200 baud half duplex asynchronous). The built–in differential line driver has the capability of driving 0 dBm into a 600 Ω load with a 5 V single power supply. This device also includes a DTMF generator, DTMF receiver, call–progress tone detector, answer tone generator, and a receive timing control circuit. Besides having a clock generator with a crystal oscillator connected to it, the device has a divider circuit to which input of a double frequency clock is possible from external sources, such as from a microcontroller unit (MCU). The serial control port (SCP) permits the MCU to access internal registers for exercising the built–in features. A low consumption device, the MC145745 integrates various functions in a small package. This modem IC is best suited for telemeter and other applications of this type. Conforms to ITU V.21 and V.23 Recommendations DTMF Generator and Receiver for all 16 Standard Digits Capable of Driving 0 dBm into a 600 Ω Load (VCC = 5 V) Automatic Gain Control (AGC) Amplifier for the DTMF Receiver Call–Progress Tone Detector Four–Wire Serial Data Interface (SCP) Programmable Transmission and Carrier Detection Levels FSK/DTMF Analog Loopback Self–Test Function Crystal Oscillator (3.579545 MHz) ...