ISG3300A1
FEATURES
• TWO WAY DOCSIS COMPLIANT:
91-860 MHz Downstream
5-42 MHz Upstream
• INTERFACES DIRECTLY WITH QAM DEMOD/MOD ICs
• INCORPORATES ALL RF FILTERS INCLUDING
TX ANTI ALIASING
• DIGITAL LINEAR RF TRANSMITTER:
All Harmonics -51 dBc @ 58 dBmv : ≥ 50 dB Combined
Gain Control w/ Digital Step Attenuator
• SUPERIOR SNR:
37 dB for 64 QAM / 35 dB for 256 QAM (TYP)
• RUGGED DESIGN/NO MICROPHONICS:
SMD Components, "Coiless"
5 V CATV MODEM RF TRANSCEIVER
DESCRIPTION AND APPLICATIONS
The ISG3300A1 is a complete RF transceiver designed for use
in cable modem applications. The transceiver integrates a
diplex filter, triple conversion receiver and transmit AGC
amplifier (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 desired IF sampling frequency. It also
provides the necessary gain control input power to the DSP.
The RF transmitter section combined with the digital modulator
provides a digitally controlled gain range of ≥ 50 dB, while
maintaining excellent linearity performance.
California Eastern Laboratories
PRELIMINARY DATA SHEET
ELECTRICAL CHARACTERISTICS (VCC = 5 V, VCC2 = 24 V, TA = 25°C)
Notes:
1. Optional Output Frequency of 43.75 MHz Available
2. 110 Channels at +15 dBmV/tone
PART NUMBER ISG3300A1
SYMBOLS PARAMETERS UNITS MIN TYP MAX
RF Performance (RX)
fOP Operating Frequency Range MHz 91 860
Input Signal Level dBmV -20 15
Gain Range dB 25 75
VAGC Automatic Gain Control Voltage RF 0 3.3
VAGC Automatic Gain Control Voltage IF 0 3.3
NFMAX Noise Figure (Max Gain) dB 8 10
Phase Noise at 10 kHz Offset dBc/Hz -83 -80
LO Radiation at RF Input dBm -40
Resolution KHz 62.5
Lock Time (end to end channel) msec. 18
Input Impedance (Nominal) ohms 75
RLIN Input Return Loss dB 6
Channel Bandwidth USA MHz 6
Output Frequency1MHz 5.70 5.75 5.80
Passband Ripple dB 1 2
Image Rejection dB 50
Inband Group Delay ns 100
CSO2dBc 45
CTB2dBc 45
Frequency Offset KHz -35 +35
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