IF Baseband Processing
High-linearity, low-noise baseband ICs from Hittite
Hittite’s IF/Baseband Processing integrated-circuit product line includes two baseband-compatible products that combine excellent performance with flexibility and low cost. The HMC960LP4E dual digital variable gain amplifier and the HMC900LP5E dual-programmable low-pass filter with driver, meet the demand for a universal multi-standard, wideband/carrier transceiver, which is compact and capable of processing complex high-density constellation signals.
The HMC960LP4E is a dual-channel, digitally-programmable, differential variable gain amplifier. It supports discrete gain levels from 0 to 40 dB, in 0.5 dB steps which are smooth and precise. The dual-differential HMC900LP5E filter features 0 or 10 dB input gain settings and supports arbitrary bandwidths from 3.5 MHz to 50 MHz. Once calibrated, the accuracy is ±2.5% of the desired bandwidth. The 6th order Butterworth transfer function delivers superior stop-band rejection while maintaining both a flat pass band and minimal group delay variation.
The HMC960LP4E can be combined with the HMC900LP5E to provide a complete, direct down-conversion baseband line-up that drives a pair of Hittite I/Q channel Analog-to-Digital Converters (ADCs). In such a design, Hittite's HMCAD1520 12-bit ADC with its dual-channel, 320 MSPS sampling rate would provide the common-mode control voltage to the variable gain amplifier HMC960LP4E, a feature that greatly simplifies the ADC interface.
The HMC960LP4E and the HMC900LP5E offer high linearity, very-low noise, excellent quadrature balance, high precision, and superior RF isolation between channels. These features enable the receiver designer to overcome the challenge of rejecting out-of-channel interferers while maintaining a perfect noise versus linearity trade-off.
The HMC960LP4E is housed in a 4 x 4 mm plastic leadless surface-mount package and the HMC900LP5E is housed in a 5 x 5 mm plastic leadless surface-mount package. Both products provide excellent temperature stability from -40°C to +85°C.