MV3507 Datasheet | Zarlink Semiconductor

TURES s Low Power CMOS 80m W (Operating) 10m W (Standby) s Meets or Exceeds AT & T3, and CCITT G.711, G.712 and G.733 Specifications s Input Analog Filter Eliminates Need for External Antialiasing Prefilter s Unmitted Input and Output Op. Amps for Programming Gain s Output Op. Amp Provides ±3.1V into a 1200 Ohms Load or can be Switched Off for Reduced Power (70m W) s Encoder has Dual-speed Auto-zero Loop for Fast Acquisition on Power-up s Low Absolute Group Delay = 410 microseconds at 1 k Hz DG22 Figure 1: Pin connection - top view MV3506/7/8 FUNCTIONAL DESCRLPTION Fig.2 shows the simplified block diagram of the devices. They contain independent circuitry for processing transmit and receive signals. Switched capacitor filters provide the necessary bandwidth limiting of voice signals in both directions. Circuitry for coding and decoding operates on the principle of successive approximation, using charge redistribution in a binary weighted capacitor array to define segments and a resistor chain to define steps. TRANSMIT SECTION Input analog signals first enter the chip at the unmitted op.amp. terminals (IN+ and IN- pins). This allows for the gain in the system to be trimmed. From the VIN pin the signal enters a second-order analog anti-aliasing filter. This filter eliminates the need for any off-chip filtering as it provides attenuation of 34d B (typically) at 256k Hz and 44d B (typically) at 512k Hz. The signal next enters the transmit filter, which is a fifth order low-pass filter clocked at 256k Hz, followed by a third order high-pass filter clocked at 64k Hz. The resulting bandpass characteristics meet the CCITT specifications G.711, G.712 and G.733. Some representative attenuations are better than 26d B from 0 to 60Hz and better than 35d B from 4.6k Hz to 100k Hz....