PT2325 6 Channel Volume Control DESCRIPTION The volume controller is a basic function in an audio system, in a modern multi-channel system always needs a main volume that can adjust volume of all channels in synchronously. In traditional multi-channel design mostly utilizing a multi-gang potentiometer, but it’s so expensive and not easy to achieved well volume attenuation matching between each channel. Now a better solution is uses the PT2325 to replace the multi-gang potentiometer. The PT2325 is designed for multi-channel audio purpose, the chip has 6 groups built-in 48 steps volume attenuator for each channel and running in synchronous, it only needs an external DC voltage to setting volume attenuation. In general application, a cheap single-gang potentiometer is work well to control whole channel’s volume. The DC volume setting also can be controlled by a PWM signal from the MCU and support 3.3V MCU bus voltage. FEATURES • 6 channels, volume control range 0 ~ -100dB/per channel • Operating voltage range: - Volume buffer : 5 ~ 10V - Volume controller: 3.3 ~ 10V • Low noise, High SNR: Greater than 100dB (A-Weighted) • High channel separation > 100dB • Built-in MUTE function • DC controlled volume attenuation The performance of the PT2325 is excellent for the high cost/performance multi-channel audio system, its wide attenuation range (down to -100dB), high channel separation characteristics is also suite for other high quality audio purpose. APPLICATIONS • • • • AV surround system Mini combo PC multimedia speaker Other audio applications Tel: 886-66296288‧Fax: 886-29174598‧ http://www.princeton.com.tw‧2F, 233-1, Baociao Road, Sindian, Taipei 23145, Taiwan PT2325 APPLICATION CIRCUIT Notes: 1. Cadj is for volume controller calibration purpose, the osc frequency is 1MHz when Cadj=100pF. 2. The DC block coupling capacitor (1µF) placed in every input and output pin must care the polarity, the positive polarity side of cap must toward the higher potential for proper operation. If not may cause abnormal pop noise during volume is changed. V1.2 2 March 2010 PT2325 ORDER INFORMATION Valid Part Number PT2325-D PT2325-X Package Type 20 Pin, DIP, 300mil 20 Pin, SSOP, 150mil Top Code PT2325-D PT2325-X PIN CONFIGURATION PIN DESCRIPTION Pin Name I/O Description IN1 I Channel.1 input, AC coupling to audio source IN2 I Channel.2 input, AC coupling to audio source IN3 I Channel.3 input, AC coupling to audio source VccA - Power Supply for internal amplifier REF - 1/2 VccA reference bypassing, connect a capacitor to ground GNDA - Ground Pin for amplifier MUTE I Mute pin. Connect to the VccA active the mute function IN4 I Channel.4 input, AC coupling to audio source IN5 I Channel.5 input, AC coupling to audio source IN6 I Channel.6 input, AC coupling to audio source OUT6 O Channel.6 output, AC coupling to next stage OUT5 O Channel.5 output, AC coupling to next stage OUT4 O Channel.4 output, AC coupling to next stage FREQ_ADJ - Oscillator Frequency adjustment for the volume controller GNDV - Ground Pin for the volume controller VOLUME I DC voltage input for the volume controller VccV - Power Supply input for the volume controller OUT3 O Channel.3 output, AC coupling to next stage OUT2 O Channel.2 output, AC coupling to next stage OUT1 O Channel.1 output, AC coupling to next stage V1.2 3 Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 March 2010 PT2325 IMPORTANT NOTICE Princeton Technology Corporation (PTC) reserves the right to make corrections, modifications, enhancements, improvements, and other changes to its products and to discontinue any product without notice at any time. PTC cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a PTC product. No circuit patent licenses are implied. Princeton Technology Corp. 2F, 233-1, Baociao Road, Sindian, Taipei 23145, Taiwan Tel: 886-2-66296288 Fax: 886-2-29174598 http://www.princeton.com.tw V1.2 4 March 2010