QUAD NON-PROGRAMMABLE PCM CODEC DESCRIPTION FEATURES * * * * * * * * * * IDT821024 4 channel CODEC with on-chip digital filters Selectable A-law or -law companding Master clock frequency selection: 2.048 MHz, 4.096 MHz or 8.192 MHz - Internal timing automatically adjusted based on MCLK and frame sync signal Separate PCM and master clocks Single PCM port with up to 8.192 MHz data rate (128 time slots) Transhybrid balance impedance hardware adjustable via external components Transmit gains hardware adjustable via external components Low power +5.0 V CMOS technology +5.0 V single power supply Package available: 32 pin PLCC, 44 pin TQFP The IDT821024 is a single-chip, four channel PCM CODEC with onchip filters. The device provides analog-to-digital and digital-to-analog conversions and supports both a-law and -law companding. The digital filters in IDT821024 provides the necessary transmit and receive filtering for voice telephone circuit to interface with time-division multiplexed systems. All of the digital filters are performed in digital signal processors operating from an internal clock, which is derived from MCLK. The fixed filters set the transmit and receive gain and frequency response. In the IDT821024 the PCM data is transmitted to and received from the PCM highway in time slots determined by the individual Frame Sync signals (FSRn and FSXn, where n = 1-4) at rates from 256 KHz to 8.192 MHz. Both Long and Short Frame Sync modes are available in the IDT821024. The IDT821024 can be used in digital telecommunication applications such as PBX, Central Office Switch, Digital Telephone and Integrated Voice/ Data Access Unit. FUNCTIONAL BLOCK DIAGRAM IIN1 VOUT1 IIN2 VOUT2 Anolog Front End CH1 PCM TSA 1 PCM TSA 2 Anolog Front End CH2 PCM TSA 3 DSP VOUT4 MCLK IREF FSX2 FSR2 FSX3 FSR3 FSX4 FSR4 DX PCM Interface Anolog Front End CH4 TSC DR PCLK Clock & Reference Circuits PDN 1~ 4 Control VCCA CNF FSR1 A/ DGND IIN4 PCM TSA 4 VCCD VOUT3 Anolog Front End CH3 AGND IIN3 FSX1 The IDT logo is a registered trademark of Integrated Device Technology, Inc INDUSTRIAL TEMPERATURE RANGE FEBRUARY 9, 2009 1 2003 Integrated Device Technology, Inc. DSC-6034/4 IDT821024 QUAD NON-PROGRAMMABLE PCM CODEC INDUSTRIAL TEMPERATURE RANGE VOUT1 CNF PDN1 PDN2 PDN3 PDN4 MCLK 4 3 2 1 32 31 30 PIN CONFIGURATIONS 5 29 PCLK IIN2 6 28 TSC VOUT2 7 27 DGND VCCA 8 26 DX IREF 9 25 VCCD AGND 10 24 DR VOUT3 11 23 FSR1 IIN3 12 22 FSX1 IIN4 13 21 FSR2 FSR3 FSX2 PDN3 PDN4 MCLK PCLK 37 36 35 34 19 FSX3 PDN2 38 18 FSR4 PDN1 39 17 FSX4 NC 40 16 15 41 A/ NC 42 CNF VOUT1 43 14 IIN1 44 VOUT4 32-Pin PLCC 20 IIN1 IIN2 1 33 NC VOUT2 2 32 NC NC 3 31 TSC NC 4 30 DGND VCCA 5 29 NC IREF 6 28 DX AGND 7 27 VCCD NC 8 26 DR NC 9 25 FSR1 VOUT3 10 24 FSX1 IIN3 11 23 FSR2 12 13 14 15 16 17 18 19 20 21 22 IIN4 VOUT4 NC NC A/ NC FSX4 FSR4 FSX3 FSR3 FSX2 44-Pin TQFP 2 IDT821024 QUAD NON-PROGRAMMABLE PCM CODEC INDUSTRIAL TEMPERATURE RANGE PIN DESCRIPTION Pin Number PLCC TQFP Name I/O AGND -- 10 7 Analog Ground. All ground pins should be connected to the ground plane of the circuit board. VCCA -- 8 5 +5 V Analog Power Supply. All power supply pins should be connected to the power plane of the circuit board. DGND -- 27 30 Digital Ground. All ground pins should be connected to the ground plane of the circuit board. VCCD -- 25 27 +5 V Digital Power Supply. All power supply pins should be connected to the power plane of the circuit board. DR I 24 26 Receive PCM Data Input. The PCM data for Channel 1, 2, 3 and 4 is shifted serially into DR pin by the Receive Frame Sync Signal (FSR) with MSB first. A byte of data for each channel is received every 125 s at the PCLK rate. DX FSR1 FSR2 FSR3 FSR4 FSX1 FSX2 FSX3 FSX4 IREF VOUT1 VOUT2 VOUT3 VOUT4 IIN1 IIN2 IIN3 IIN4 MCLK Description O 26 28 Transmit PCM Data Output. The PCM data for Channel 1, 2, 3 and 4 is shifted serially out to the DX pin by the Transmit Frame Sync Signal (FSX) with MSB first. A byte of data for each channel is transmitted every 125 s at the PCLK rate. DX is high impedance between time slots. I 23 21 19 17 25 23 21 19 Receive Frame Sync Input for Channel 1/2/3/4 This 8kHz signal pulse identifies the receive time slot for Channel N on a system's receive PCM frame. It must be synchronized to PCLK. I 22 20 18 16 24 22 20 18 Transmit Frame Sync Input for Channel 1/2/3/4 This 8 kHz signal pulse identifies the transmit time slot for Channel N on a system's transmit PCM frame. It must be synchronized to PCLK. O 9 6 Reference Current. The IREF output is biased at the internal reference voltage. A resistor placed from IREF to ground sets the reference current used by the analog-to-digital converter to encode the signal current present on IINn pin (n is channel number, n = 1 to 4) into digital form. O 4 7 11 14 43 2 10 13 Voice Frequency Receiver Output for Channel 1/2/3/4 This is the output of receiver amplifier for Channel N. The received digital data from DR is processed and converted to an analog signal at this pin. I 5 6 12 13 44 1 11 12 Voice Frequency Transmitter Input for Channel 1/2/3/4 This is the input to the gain setting amplifier in the transmit path for Channel N. The analog voice band voltage signal is applied to this pin through a resistor. This input is a virtual AC ground input, which is biased at the IREF pin. 35 Master Clock. The Master Clock provides the clock for the DSP. It can be either 2.048 MHz or 4.096 MHz. The IDT821024 determines the MCLK frequency via the FSX inputs and makes the necessary internal adjustments automatically. The MCLK frequency must be an integer multiple of the FSX frequency. I 30 PCLK I 29 34 PCM Clock. The PCM Clock shifts out the PCM data to the DX pin and shifts in PCM data from the DR pin. The PCM clock frequency is an integer multiple of the frame sync frequency. When PCLK is connected to MCLK, the PCM clock can generate the DSP clock as well. TSC O 28 31 Time Slot Control. This open drain output is low active. When the PCM data is transmitted to the DX pin for any of the four channels, this pin will be pulled low. A/ I 15 16 A/ -Law Selection. When this pin is low, -Law is selected; when this pin is high, A-Law is selected. This pin can be connected to VCCD or DGND pin directly. 3 IDT821024 QUAD NON-PROGRAMMABLE PCM CODEC INDUSTRIAL TEMPERATURE RANGE PIN DESCRIPTION (cont'd) Name PDN1 PDN2 PDN3 PDN4 CNF NC I/O Pin Number PLCC TQFP Description I 2 1 32 31 39 38 37 36 Channel 1/2/3/4 Power Down. When this pin is high, Channel N is powered down. O 3 41 Capacitor For Noise Filter. This pin should be connected to AGND through a 0.1 F capacitor. -- 3, 4, 8, 9, 14, 15, 17, 29, 32, 33, 40, 42 No connection 4 IDT821024 QUAD NON-PROGRAMMABLE PCM CODEC INDUSTRIAL TEMPERATURE RANGE FUNCTIONAL DESCRIPTION and compressed to PCM format. The IDT821024 contains four channel PCM CODEC with on chip digital filters. It provides the four-wire solution for the subscriber line circuitry in digital switches. The device converts analog voice signal to digital PCM data, and converts digital PCM data back to analog signal. Digital filters are used to bandlimit the voice signals during the conversion. Either A-law or -law is supported by the IDT821024. The law selection is performed by A/ pin. The frequency of the master clock (MCLK) can be 2.048 MHz, 4.096 MHz, or 8.192 MHz. Internal circuitry determines the master clock frequency automatically. The serial PCM data for four channels are time multiplexed via two pins, DX and DR. The time slots of the four channels are determined by the individual Frame Sync signals at rates from 256 kHz to 8.192 MHz. For each channel, the IDT821024 provides a transmit Frame Sync signal and a receive Frame Sync signal. Each channel of the IDT821024 can be powered down independently to save power consumption. The Channel Power Down Pins PDN1-4 configure channels to be active (power-on) or standby (power-down) separately. Transmit PCM Interface The transmit PCM interface clocks out 1 byte (8 bits) PCM data out of DX pin every 125 s. The transmit logic, synchronized by the Transmit Frame Sync signal (FSXn), controls the data transmission. The FSXn pulse identifies the transmit time slot of the PCM frame for Channel N. The PCM Data is transmitted serially on DX pin with the Most Significant Bit (MSB) first. When the PCM data is being output on DX pin, the TSC signal will be pulled low. Receive Signal Processing In the receive path, the PCM code is received at the rate of 8,000 samples per second. The PCM code is expanded and sent to the DSP for interpolation. A receive filter is implemented in the DSP as a digital lowpass filter. The filtered signal is then sent to an oversampling DAC. The DAC output is post-filtered and delivered at VOUT pin by an amplifier. The amplifier can drive resistive load higher than 2 K. Receive PCM Interface The receive PCM interface clocks 1 byte (8 bits) PCM data into DR pin every 125 s. The receive logic, synchronized by the Receive Frame Sync signal (FSRn), controls the data receiving process. The FSRn pulse identifies the receive time slot of the PCM frame for Channel N. The PCM Data is received serially on DR pin with the Most Significant Bit (MSB) first. Signal Processing High performance oversampling Analog-to-Digital Converters (ADC) and Digital-to-Analog Converters (DAC) are used in the IDT821024 to provide the required conversion accuracy. The associated decimation and interpolation filtering are realized with both dedicated hardware and Digital Signal Processor (DSP). The DSP also handles all other necessary functions such as PCM bandpass filtering and sample rate conversion. Hardware Gain Setting In Transmit Path The transmit gain of the IDT821024 for each channel can be set by 2 resistors, RREF and RTXn (as shown in Figure 1), according to the following equation: Transmit Signal Processing In the transmit path, the analog input signal is received by the ADC and converted into digital data. The digital output of the oversampling ADC is decimated and sent to the DSP. The transmit filter is implemented in the DSP as a digital bandpass filter. The filtered signal is further decimated to SLIC VTX Gt = The receive gain of IDT821024 is fixed and equal to 1. IDT821024 CTX1 RTX1 A/D I REF VIN1 V REF to IREF Bal Net to SLIC RSN 3 x R REF R TXn RRX 1 IREF1 VREF1 CRX1 VOUT1 RREF1 CFIL VREF D/A Figure 1. IDT821024 Transmit Gain Setting for Channel 1 5 IDT821024 QUAD NON-PROGRAMMABLE PCM CODEC INDUSTRIAL TEMPERATURE RANGE OPERATING THE IDT821024 The following descriptions about operation applies to all four channels of the IDT821024. Power-on Sequence and Master Clock Configuration To power on the IDT821024 users should follow this sequence: 1. Apply ground; 2. Apply VCC, finish signal connections; 3. Set PDN1-4 pins high, thus all of the 4 channels are powered down; The master clock (MCLK) frequency of IDT821024 can be configured as 2.048 MHz, 4.096 MHz or 8.192 MHz. Using the Transmit Frame Sync (FSX) inputs, the device determines the MCLK frequency and makes the necessary internal adjustments automatically. The MCLK frequency must be an integer multiple of the Frame Sync frequency. Operating Modes There are two operating modes for each transmit or receive channel: standby mode (when the channel is powered down) and normal mode (when the channel is powered on). The mode selection of each channel is done by its corresponding PDN pin. When PDNn is 1, Channel N is in standby mode; when PDNn is 0, Channel N is in normal mode. In standby mode, all circuits are powered down with the analog outputs placed in high impedance state. In normal mode, each channel of the IDT821024 is able to transmit and receive both PCM and analog information. The normal mode is used when a telephone call is in progress. Companding Law Selection An A/ pin is provided by IDT821024 for the companding law selection. When this pin is low, -law is selected; when the pin is high, A-law is selected. 6 IDT821024 QUAD NON-PROGRAMMABLE PCM CODEC INDUSTRIAL TEMPERATURE RANGE ABSOLUTE MAXIMUM RATINGS Rating Power Supply Voltage Voltage on Any Pin with Respect to Ground Package Power Dissipation Storage Temperature Com'I & Ind'I 6.5 -0.5 to 5.5 Unit V V 600 -65 to +150 mW C RECOMMENDED DC OPERATING CONDITIONS Parameter Operating Temperature Power Supply Voltage Min. -40 4.75 Typ. Max. +85 5.25 Unit C V NOTE: MCLK: 2.048 MHz, 4.096 MHz or 8.192 MHz with tolerance of 50 ppm NOTE: Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. ELECTRICAL CHARACTERISTICS Digital Interface Parameter V IL VIH V OL Description Input Low Voltage Input High Voltage Output Low Voltage Min Typ Max 0.8 VDD-0.6 V V Test Conditions All digital inputs All digital inputs DX, TSC,IL = 14mA All other digital outputs, IL = 4mA. All digital pins, IL = 14mA DX, IH = -7 mA, all other outputs, IH = -4 mA VDD-0.2 V All digital pins, IH = -1mA 2.0 0.4 0.8 Units V V V V 0.2 VOH II IOZ CI Output High Voltage Input Current Output Current in High-impedance State Input Capacitance -10 -10 10 10 5 A A pF Any digital inputs GND