ISG4042-T

ISG4042-T 5 V CATV MODEM RF TUNER AND TRANSMITTER FEATURES • TWO WAY DOCSIS BASED DESIGN: 91-857 MHz Downstream 5-42 MHz Upstream • SINGLE SUPPLY 5 V OPERATION: With Built in Linear Regulation • SINGLE AGC CONTROL Simplifies Modem Calibration • ULTRA SMALL SIZE: 1.9 x 2.0 x 0.5 in., 1.9 in3 46.2 x 49.0 x 12.5 mm., 28.5 cc. • DIGITAL LINEAR RF TRANSMITTER: All Harmonics meets DOCSIS @ 58 dBmV (see note 2) > 56 dB Gain Range (0.5 dB steps) • INTERFACES DIRECTLY WITH QAM MOD/DEMOD IC's: (see note 3) DESCRIPTION AND APPLICATIONS The ISG4042-T is an RF tuner/transmitter designed for use in DOCSIS cable modem applications. It is a complete solution that interfaces directly with QAM Mod/Demod IC's. The tuner/ transmitter integrates a diplex filter, dual conversion receiver, transmit AGC amplifier, and other RF filtering (see Figure 1). The diplex filter provides over 40 dB of isolation between the TX band and the RX band. The receiver channel selects and converts QAM signals in the RX band down to the IF sampling frequency. It also provides the necessary gain control to adjust the input power to the DSP chip. The RF transmitter section provides > 56 dB of digitally controlled range while maintaining excellent linearity performance. ELECTRICAL CHARACTERISTICS (VCC = 5 V, ±2 %, TA = 25°C) (see note 4) SYMBOLS RF Performance (RX) fOP Operating Frequency Range (Center to Center) Input Signal Level Maximum Voltage Gain Automatic Voltage Gain Control Range IF Automatic Voltage Gain Cont...