MX029

DATA BULLETIN MX029 Features     Dual Digitally Controlled Amplifier PRELIMINARY INFORMATION Applications      Cellular and LMR Radios PABX’s, Electronic Mail, TAM's Automatic Test Equipment Remote Gain Adjustments Digitally Set Audio Control Levels 2 Digitally Controlled Amplifiers ±48dB Gain/Attenuation in 2dB Steps + Mute Individual Control with a 14-Bit Serial Word Separate Fixed Gain Buffer Amplifier SERIAL CLOCK DATA INPUT LOAD/LATCH SERIAL INTERFACE VDD STAGE 1 CONTROL REGISTER VSS BIAS VSS BIAS CH1, INPUT 1 CH1, INPUT 2 CH1, INPUT 3 TO STAGE 1 CONTROL REGISTER CH1, OUTPUT 1 ∆G CH1, OUTPUT 2 VSS BIAS STAGE 1 CONTROL REGISTER VSS CH2, INPUT 1 BIAS ∆G CH2, INPUT 2 CH2, OUTPUT 1 UNIVERSAL AMP IN UNIVERSAL AMP OUT BIAS The MX029 Digitally Controlled Amplifier Array replaces audio level controls in radio and wireline communications applications. It is a single-chip LSI circuit comprised of two discrete, digitally controlled gain sections. Each section has 48 distinct gain steps (+/-48dB of range in 2dB steps) plus MUTE. As shown in Figure 1, both gain stages have switchable inputs. This switching allows for selection of three different input signals on one channel and two on the other channel. One of the channels also has output switching. In addition to two digitally controlled gain stages, there is a general purpose inverting amplifier. The gain of this amplifier is controlled externally via negative feedback. Control of each gain control sec...