XL3057W

XL3057W SOP16 General Description Features XL3057W family consists of A-law monolithic PCM CODEC/filters utilizing the D/A conversion architecture shown inFigure 1, and a serial PCM interface. The encode portion of each device consists of an input gain adjust amplifier, an active RC pre-filter which eliminates very high frequency noise prior to entering a switched-capacitor band-pass filter that rejects signals below 200 Hz and above 3400 Hz. Also included are auto-zero circuitry and a companding coder which samples the filtered signal and encodes it in the companded m-law or A-law PCM format. The decode portion of each device consists of an expanding decoder, which reconstructs the analog signal from the companded m-law or A-law code, a low-pass filter which corrects for the sin x/x response of the decoder output and rejects signals above 3400 Hz followed by a single-ended power amplifier capable of driving low impedance loads. The devices require two 1.536 MHz, 1.544 MHz or 2.048 MHz transmit and receive master clocks, which may be asynchronous; transmit and receive bit clocks, which may vary from 64 kHz to 2.048 MHz; and transmit and receive frame sync pulses. The timing of the frame sync pulses and PCM data is compatible with both industry standard formats. Y Complete CODEC and filtering system (COMBO) including: Ð Transmit high-pass and low-pass filtering Ð Receive low-pass filter with sin x/x correction Ð Active RC noise filters Ð m-law or A-law compatible COder and DECoder Ð Internal precision voltage reference Ð Serial I/O interface Ð Internal auto-zero circuitry Y A-law, 16-pinÐ XL3057W Designed for D3/D4 and CCITT applications g 5V operation Low operating powerÐtypically 50 mW Power-down standby modeÐtypically 3 mW Automatic power-down TTL or CMOS compatible digital interfaces Maximizes line interface card circuit density Dual-In-Line or surface mount packages Y Y Y Y Y Y Y Y Connection Diagrams SOP16 XL3057W 1 XL3057W SOP16 Block Diagram Pin Description Symbol VBB GNDA Symbol Function Negative power supply pin. VBB e b5V g 5%. Analog ground. All signals are referenced to this pin. VFRO Analog output of the receive power amplifier. VCC Positive power supply pin. VCC e a 5V g 5%. FSR Receive frame sync pulse which enables BCLKR to shift PCM data into DR. FSR is an 8 kHz pulse train. See Figures 2 and 3 for timing details. DR Receive data input. PCM data is shifted into DR following the FSR leading edge. BCLKR/CLKSEL The bit clock which shifts data into DR after the FSR leading edge. May vary from 64 kHz to 2.048 MHz. Alternatively, may be a logic input which selects either 1.536 MHz/1.544 MHz or 2.048 MHz for master clock in synchronous mode and BCLKX is used for both transmit and receive directions (see Table I). MCLKR/PDN Receive master clock. Must be 1.536 MHz, 1.544 MHz or 2.048 MHz. May be asynchronous with MCLKX, but MCLKX FSX BCLKX DX TSX GSX VFXIb VFXI a 2 Function should be synchronous with MCLKX for best performance. When MCLKR is connected continuously low, MCLKX is selected for all internal timing. When MCLKR is connected continuously high, the device is powered down. Transmit master clock. Must be 1.536 MHz, 1.544 MHz or 2.048 MHz. May be asynchronous with MCLKR. Best performance is realized from synchronous operation. Transmit frame sync pulse input which enables BCLKX to shift out the PCM data on DX. FSX is an 8 kHz pulse train, see Figures 2 and 3 for timing details. The bit clock which shifts out the PCM data on DX. May vary from 64 kHz to 2.048 MHz, but must be synchronous with MCLKX. The TRI-STATEÉ PCM data output which is enabled by FSX. Open drain output which pulses low during the encoder time slot. Analog output of the transmit input amplifier. Used to externally set gain. Inverting input of the transmit input amplifier. Non-inverting input of the transmit input amplifier. XL3057W SOP16 Functional Description POWER-UP ASYNCHRONOUS OPERATION When power is first applied, power-on reset circuitry initializes the COMBO and places it into a power-down state. All non-essential circuits are deactivated and the DX and VFRO outputs are put in high impedance states. To power-up the device, a logical low level or clock must be applied to the MCLKR/PDN pin and FSX and/or FSR pulses must be present. Thus, 2 power-down control modes are available. The first is to pull the MCLKR/PDN pin high; the alternative is to hold both FSX and FSR inputs continuously lowÐthe device will power-down approximately 1 ms after the last FSX or FSR pulse. Power-up will occur on the first FSX or FSR pulse. The TRI-STATE PCM data output, DX, will remain in the high impedance state until the second FSX pulse. For asynchronous operation, separate transmit and receive clocks may be applied. MCLKX and MCLKR must be 2.048 MHz for the XL3057W, or 1.536 MHz, 1.544 MHz for the logic levels to the MCLKR/PDN pin. This will automatically connect MCLKX to all internal MCLKR functions (see Pin Description). For 1.544 MHz operation, the device automatically compensates for the 193rd clock pulse each frame. FSX starts each encoding cycle and must be synchronous with MCLKX and BCLKX. FSR starts each decoding cycle and must be synchronous with BCLKR. BCLKR must be a clock, the logic levels shown in Table 1 are not valid in asynchronous mode. BCLKX and BCLKR may operate from 64 kHz to 2.048 MHz. SYNCHRONOUS OPERATION For synchronous operation, the same master clock and bit clock should be used for both the transmit and receive directions. In this mode, a clock must be applied to MCLKX and the MCLKR/PDN pin can be used as a power-down control. A low level on MCLKR/PDN powers up the device and a high level powers down the device. In either case, MCLKX will be selected as the master clock for both the transmit and receive circuits. A bit clock must also be applied to BCLKX and the BCLKR/CLKSEL can be used to select the proper internal divider for a master clock of 1.536 MHz, 1.544 MHz or 2.048 MHz. For 1.544 MHz operation, the device automatically compensates for the 193rd clock pulse each frame. With a fixed level on the BCLKR/CLKSEL pin, BCLKX will be selected as the bit clock for both the transmit and receive directions. Table 1 indicates the frequencies of operation which can be selected, depending on the state of BCLKR/ CLKSEL. In this synchronous mode, the bit clock, BCLKX, may be from 64 kHz to 2.048 MHz, but must be synchronous with MCLKX. Each FSX pulse begins the encoding cycle and the PCM data from the previous encode cycle is shifted out of the enabled DX output on the positive edge of BCLKX. After 8 bit clock periods, the TRI-STATE DX output is returned to a high impedance state. With an FSR pulse, PCM data is latched via the DR input on the negative edge of BCLKX (or BCLKR if running). FSX and FSR must be synchronous with MCLKX/R. SHORT FRAME SYNC OPERATION The COMBO can utilize either a short frame sync pulse or a long frame sync pulse. Upon power initialization, the device assumes a short frame mode. In this mode, both frame sync pulses, FSX and FSR, must be one bit clock period long, with timing relationships specified in Figure 2 . With FSX high during a falling edge of BCLKX, the next rising edge of BCLKX enables the DX TRI-STATE output buffer, which will output the sign bit. The following seven rising edges clock out the remaining seven bits, and the next falling edge disables the DX output. With FSR high during a falling edge of BCLKR (BCLKX in synchronous mode), the next falling edge of BCLKR latches in the sign bit. The following seven falling edges latch in the seven remaining bits. All four devices may utilize the short frame sync pulse in synchronous or asynchronous operating mode. LONG FRAME SYNC OPERATION To use the long frame mode, both the frame sync pulses, FSX and FSR, must be three or more bit clock periods long, with timing relationships specified in Figure 3 . Based on the transmit frame sync, FSX, the COMBO will sense whether short or long frame sync pulses are being used. For 64 kHz operation, the frame sync pulse must be kept low for a minimum of 160 ns. The DX TRI-STATE output buffer is enabled with the rising edge of FSX or the rising edge of BCLKX, whichever comes later, and the first bit clocked out is the sign bit. The following seven BCLKX rising edges clock out the remaining seven bits. The DX output is disabled by the falling BCLKX edge following the eighth rising edge, or by FSX going low, whichever comes later. A rising edge on the receive frame sync pulse, FSR, will cause the PCM data at DR to be latched in on the next eight falling edges of BCLKR (BCLKX in synchronous mode). All four devices may utilize the long frame sync pulse in synchronous or asynchronous mode. In applications where the LSB bit is used for signalling with FSR two bit clock periods long, the decoder will interpret the lost LSB as ‘‘(/2’’ to minimize noise and distortion. TABLE I. Selection of Master Clock Frequencies BCLKR/CLKSEL Master Clock Frequency Selected XL3057W Clocked 0 1 2.048 MHz 1.536 MHz or 1.544 MHz 2.048 MHz 3 XL3057W SOP16 Functional Description (Continued) TRANSMIT SECTION RECEIVE SECTION The receive section consists of an expanding DAC which drives a fifth order switched-capacitor low pass filter clocked at 256 kHz. The decoder is A-law XL3057W the 5th order low pass filter corrects for the sin x/x attenuation due to the 8 kHz sample/hold. The filter is then followed by a 2nd order RC active post-filter/ power amplifer capable of driving a 600X load to a level of 7.2 dBm. The receive section is unity-gain. Upon the occurrence of FSR, the data at the DR input is clocked in on the falling edge of the next eight BCLKR (BCLKX) periods. At the end of the decoder time slot, the decoding cycle begins, and 10 ms later the decoder DAC output is updated. The total decoder delay is E 10 ms (decoder update) plus 110 ms (filter delay) plus 62.5 ms ((/2 frame), which gives approximately 180 ms. The transmit section input is an operational amplifier with provision for gain adjustment using two external resistors, see Figure 4. The low noise and wide bandwidth allow gains in excess of 20 dB across the audio passband to be realized. The op amp drives a unity-gain filter consisting of RC active pre-filter, followed by an eighth order switched-capacitor bandpass filter clocked at 256 kHz. The output of this filter directly drives the encoder sample-and-hold circuit. The A/D is of companding type according to m-law XL3057W coding conventions. A precision voltage reference is trimmed in manufacturing to provide an input overload (tMAX) of nominally 2.5V peak (see table of Transmission Characteristics). The FSX frame sync pulse controls the sampling of the filter output, and then the successive-approximation encoding cycle begins. The 8-bit code is then loaded into a buffer and shifted out through DX at the next FSX pulse. The total encoding delay will be approximately 165 ms (due to the transmit filter) plus 125 ms (due to encoding delay), which totals 290 ms. Any offset voltage due to the filters or comparator is cancelled by sign bit integration. 4 XL3057W SOP16 Voltage at any Digital Input or Output Absolute Maximum Ratings VCC to GNDA 7V VBB to GNDA b 7V Voltage at any Analog Input or Output VCC a 0.3V to VBBb0.3V Electrical Characteristics VCC a 0.3V to GNDAb0.3V b 25§ C to a 125§ C Operating Temperature Range b 65§ C to a 150§ C Storage Temperature Range Lead Temperature (Soldering, 10 seconds) 300§ C ESD (Human Body Model) 2000V Latch-Up Immunity e 100 mA on any Pin Unless otherwise noted, limits printed in BOLD characters are guaranteed for VCC e 5.0V g 5%, VBB e b 5.0V g 5%; TA e 0§ C to 70§ C by correlation with 100% electrical testing at TA e 25§ C. All other limits are assured by correlation with other production tests and/or product design and characterization. All signals referenced to GNDA. Typicals specified at VCC e 5.0V, VBB e b5.0V, TA e 25§ C. Symbol Parameter Conditions Min Typ Max Units 0.6 V 0.4 0.4 0.4 V V V DIGITAL INTERFACE VIL Input Low Voltage VIH Input High Voltage VOL Output Low Voltage DX, IL e 3.2 mA SIGR, IL e 1.0 mA TSX, IL e 3.2 mA, Open Drain VOH Output High Voltage DX, IH eb3.2 mA SIGR, IH eb1.0 mA IIL Input Low Current GNDAsVINsVIL, All Digital Inputs b 10 10 mA IIH Input High Current VIHsVINsVCC b 10 10 mA IOZ Output Current in High Impedance State (TRI-STATE) DX, GNDAsVOsVCC b 10 10 mA 200 2.2 V 2.4 2.4 V V ANALOG INTERFACE WITH TRANSMIT INPUT AMPLIFIER (ALL DEVICES) IIXA Input Leakage Current b 2.5V s V s a 2.5V, VFXI a or VFXI b b 200 RIXA Input Resistance b 2.5V s V s a 2.5V, VFXI a or VFXI b 10 ROXA Output Resistance Closed Loop, Unity Gain RLXA Load Resistance GSX CLXA Load Capacitance GSX VOXA Output Dynamic Range GSX, RLt10 kX b 2.8 AVXA Voltage Gain VFXI a to GSX 5000 FUXA Unity Gain Bandwidth VOSXA Offset Voltage VCMXA Common-Mode Voltage CMRRXA l 60 dB CMRRXA Common-Mode Rejection Ratio DC Test 60 dB PSRRXA Power Supply Rejection Ratio DC Test 60 dB 1 3 10 X kX 50 1 nA MX 2.8 pF V V/V 2 MHz b 20 20 b 2.5 2.5 mV V ANALOG INTERFACE WITH RECEIVE FILTER (ALL DEVICES) RORF Output Resistance Pin VFRO RLRF Load Resistance VFRO e g 2.5V 1 CLRF Load Capacitance VOSRO Output DC Offset Voltage 3 X 500 pF 200 mV 600 X b 200 POWER DISSIPATION (ALL DEVICES) ICC0 Power-Down Current No Load (Note) 0.5 1.5 mA IBB0 Power-Down Current No Load (Note) 0.05 0.3 mA ICC1 Power-Up Active Current No Load 5.0 9.0 mA IBB1 Power-Up Active Current No Load 5.0 9.0 mA Note: ICC0 and IBB0 are measured after first achieving a power-up state. 5 XL3057W SOP16 Timing Specifications Unless otherwise noted, limits printed in BOLD characters are guaranteed for VCC e 5.0V g 5%, VBB e b5.0V g 5%; TA e 0§ C to 70§ C by correlation with 100% electrical testing at TA e 25§ C. All other limits are assured by correlation with other production tests and/or product design and characterization. All signals referenced to GNDA. Typicals specified at VCC e 5.0V, VBB e b5.0V, TA e 25§ C. All timing parameters are measured at VOH e 2.0V and VOL e 0.7V. See Definitions and Timing Conventions section for test methods information. Symbol Parameter Conditions Min Typ Max 1.536 1.544 2.048 Units 1/tPM Frequency of Master Clocks Depends on the Device Used and the BCLKR/CLKSEL Pin. MCLKX and MCLKR tRM Rise Time of Master Clock MCLKX and MCLKR 50 ns tFM Fall Time of Master Clock MCLKX and MCLKR 50 ns tPB Period of Bit Clock tRB Rise Time of Bit Clock tFB Fall Time of Bit Clock BCLKX and BCLKR tWMH Width of Master Clock High MCLKX and MCLKR 160 ns tWML Width of Master Clock Low MCLKX and MCLKR 160 ns tSBFM Set-Up Time from BCLKX High to MCLKX Falling Edge First Bit Clock after the Leading Edge of FSX 100 ns tSFFM Set-Up Time from FSX High to MCLKX Falling Edge Long Frame Only 100 ns tWBH Width of Bit Clock High VIH e 2.2V 160 ns tWBL Width of Bit Clock Low VIL e 0.6V 160 ns tHBFL Holding Time from Bit Clock Low to Frame Sync Long Frame Only 0 ns tHBFS Holding Time from Bit Clock High to Frame Sync Short Frame Only 0 ns tSFB Set-Up Time from Frame Sync to Bit Clock Low Long Frame Only 80 ns tDBD Delay Time from BCLKX High to Data Valid Load e 150 pF plus 2 LSTTL Loads tDBTS Delay Time to TSX Low Load e 150 pF plus 2 LSTTL Loads tDZC Delay Time from BCLKX Low to Data Output Disabled tDZF Delay Time to Valid Data from FSX or BCLKX, Whichever Comes Later tSDB Set-Up Time from DR Valid to BCLKR/X Low 50 ns tHBD Hold Time from BCLKR/X Low to DR Invalid 50 ns tSF Set-Up Time from FSX/R to BCLKX/RLow Short Frame Sync Pulse (1 Bit Clock Period Long) 50 ns tHF Hold Time from BCLKX/R Low to FSX/R Low Short Frame Sync Pulse (1 Bit Clock Period Long) 100 ns tHBFl Hold Time from 3rd Period of Bit Clock Low to Frame Sync (FSX or FSR) Long Frame Sync Pulse (from 3 to 8 Bit Clock Periods Long) 100 ns tWFL Minimum Width of the Frame Sync Pulse (Low Level) 64k Bit/s Operating Mode 160 ns 485 BCLKX and BCLKR 488 MHz MHz MHz 15725 ns 50 ns 50 ns 0 140 140 ns CL e 0 pF to 150 pF 50 165 ns CL e 0 pF to 150 pF 20 165 ns 6 ns XL3057W SOP16 7 XL3057W SOP16 Timing Diagrams (Continued) 8 XL3057W SOP16 Transmission Characteristics Unless otherwise noted, limits printed in BOLD characters are guaranteed for VCC e 5.0V g5%, VBB e b5.0V g5%; TA e 0§C to 70§C by correlation with 100% electrical testing at TA e 25§C. All other 1.02 kHz, VIN e 0 dBm0, transmit input amplifier connected for unity gain non-inverting. Typicals specified at VCC e 5.0V, VBB e b5.0V, TA e 25§C. Symbol Parameter Conditions Min Typ Max Units AMPLITUDE RESPONSE Absolute Levels (Definition of Nominal Gain) Nominal 0 dBm0 Level is 4 dBm (600X) 0 dBm0 1.2276 Vrms Virtual Decision Valve Defined Per CCITT Rec. G711 Max Overload Level XL3057W (3.14 dBm0) 2.492 VPK GXA Transmit Gain, Absolute TA e 25§ C, VCC e 5V, VBB eb5V Input at GSX e 0 dBm0 at 1020 Hz XL3057W GXR Transmit Gain, Relative to GXA f e 16 Hz f e 50 Hz f e 60 Hz f e 200 Hz f e 300 Hzb3000 Hz f e 3300 Hz f e 3400 Hz f e 4000 Hz f e 4600 Hz and Up, Measure Response from 0 Hz to 4000 Hz tMAX b 0.15 b 1.8 b 0.15 b 0.35 b 0.7 0.15 dB b 40 b 30 b 26 b 0.1 0.15 0.05 0 b 14 b 32 dB dB dB dB dB dB dB dB dB GXAT Absolute Transmit Gain Variation with Temperature Relative to GXA b 0.1 0.1 dB GXAV Absolute Transmit Gain Variation with Supply Voltage Relative to GXA b 0.05 0.05 dB GXRL Transmit Gain Variations with Level Sinusoidal Test Method Reference Level eb10 dBm0 VFXI a eb40 dBm0 to a 3 dBm0 VFXI a eb50 dBm0 to b40 dBm0 VFXI a eb55 dBm0 to b50 dBm0 b 0.2 b 0.4 b 1.2 0.2 0.4 1.2 dB dB dB TA e 25§ C, VCC e 5V, VBB eb5V Input e Digital Code Sequence for 0 dBm0 Signal at 1020 Hz XL3057W b 0.15 0.15 dB b 0.15 b 0.35 b 0.7 0.15 0.05 0 b 14 dB dB dB dB GRA Receive Gain, Absolute GRR Receive Gain, Relative to GRA f e 0 Hz to 3000 Hz f e 3300 Hz f e 3400 Hz f e 4000 Hz GRAT Absolute Receive Gain Variation with Temperature Relative to GRA b 0.1 0.1 dB GRAV Absolute Receive Gain Variation with Supply Voltage Relative to GRA b 0.05 0.05 dB GRRL Receive Gain Variations with Level Sinusoidal Test Method; Reference Input PCM Code Corresponds to an Ideally Encoded PCM Level eb 40 dBm0 to a 3 dBm0 eb 50 dBm0 to b 40 dBm0 eb 55 dBm0 to b 50 dBm0 b 0.2 b 0.4 b 1.2 0.2 0.4 1.2 dB dB dB RL e 600X b 2.5 2.5 V VRO Receive Output Drive Level 9 XL3057W SOP16 Transmission Characteristics (Continued) Unless otherwise noted, limits printed in BOLD characters are guaranteed for VCC e 5.0V g5%, VBB e b5.0V g5%; TA e 0§C to 70§C by correlation with 100% electrical testing at TA e e 0V, f e 1.02 kHz, VIN e 0 dBm0, transmit input amplifier connected for unity gain non-inverting. Typicals specified at VCC e 5.0V, VBB e b5.0V, TA e 25§C. Symbol Parameter Conditions Min Typ Max Units ENVELOPE DELAY DISTORTION WITH FREQUENCY DXA Transmit Delay, Absolute f e 1600 Hz 290 315 ms DXR Transmit Delay, Relative to DXA f e 500 Hz – 600 Hz f e 600 Hz – 800 Hz f e 800 Hz – 1000 Hz f e 1000 Hz – 1600 Hz f e 1600 Hz – 2600 Hz f e 2600 Hz – 2800 Hz f e 2800 Hz – 3000 Hz 195 120 50 20 55 80 130 220 145 75 40 75 105 155 ms ms ms ms ms ms ms DRA Receive Delay, Absolute f e 1600 Hz 180 200 ms DRR Receive Delay, Relative to DRA f e 500 Hz – 1000 Hz f e 1000 Hz – 1600 Hz f e 1600 Hz – 2600 Hz f e 2600 Hz – 2800 Hz f e 2800 Hz – 3000 Hz 70 100 145 90 125 175 ms ms ms ms ms b 40 b 30 b 25 b 20 NOISE NXP Transmit Noise, P Message Weighted XL3057W b 74 b 67 dBm0p NRP Receive Noise, P Message Weighted PCM Code Equals Positive Zero Ð XL3057W b 82 b 79 dBm0p NRS Noise, Single Frequency f e 0 kHz to 100 kHz, Loop Around Measurement, VFXI a e 0 Vrms b 53 dBm0 PPSRX Positive Power Supply Rejection, Transmit VFXI a e b50 dBm0 VCC e 5.0 VDC a 100 mVrms f e 0 kHz – 50 kHz (Note 2) Negative Power Supply Rejection, Transmit VFXI a e b50 NPSRX PPSRR NPSRR Positive Power Supply Rejection, Receive Negative Power Supply Rejection, Receive 40 dBC dBm0 VBB eb5.0 VDC a 100 mVrms f e 0 kHz – 50 kHz (Note 2) 40 dBC PCM Code Equals Positive Zero VCC e 5.0 VDC a 100 mVrms Measure VFR0 f e 0 Hz – 4000 Hz f e 4 kHz – 25 kHz f e 25 kHz – 50 kHz 40 40 36 dBC dB dB PCM Code Equals Positive Zero VBB eb5.0 VDC a 100 mVrms Measure VFR0 f e 0 Hz – 4000 Hz f e 4 kHz – 25 kHz f e 25 kHz – 50 kHz 40 40 36 dBC dB dB 10 XL3057W SOP16 Transmission Characteristics (Continued) Unless otherwise noted, limits printed in BOLD characters are guaranteed for VCC e 5.0V g5%, VBB e b5.0V g5%; TA e 0§C to 70§C by correlation with 100% electrical testing at TA e e 0V, f e 1.02 kHz, VIN e 0 dBm0, transmit input amplifier connected for unity gain non-inverting. Typicals specified at VCC e 5.0V, VBB e b5.0V, TA e 25§C. Symbol SOS Parameter Conditions Spurious Out-of-Band Signals at the Channel Output Loop Around Measurement, 0 dBm0, 300 Hz to 3400 Hz Input PCM Code Applied at DR. 4600 Hz – 7600 Hz 7600 Hz – 8400 Hz 8400 Hz – 100,000 Hz Min Typ Max Units b 30 dB b 30 b 40 b 30 dB dB dB DISTORTION STDX STDR Signal to Total Distortion Transmit or Receive Half-Channel Sinusoidal Test Method (Note 3) Level e 3.0 dBm0 e 0 dBm0 to b 30 dBm0 eb 40 dBm0 XMT RCV eb 55 dBm0 XMT RCV SFDX Single Frequency Distortion, Transmit b 46 dB SFDR Single Frequency Distortion, Receive b 46 dB IMD Intermodulation Distortion b 41 dB b 90 b 75 dB b 90 b 70 dB 33 36 29 30 14 15 dBC dBC dBC dBC dBC dBC Loop Around Measurement, VFX a eb4 dBm0 to b21 dBm0, Two Frequencies in the Range 300 Hz – 3400 Hz CROSSTALK CTX-R Transmit to Receive Crosstalk, 0 dBm0 Transmit Level f e 300 Hz – 3400 Hz DR e Quiet PCM Code CTR-X Receive to Transmit Crosstalk, 0 dBm0 Receive Level f e 300 Hz – 3400 Hz, VFXI e Multitone (Note 2) ENCODING FORMAT AT DX OUTPUT XL3057W A-Law (Includes Even Bit Inversion) VIN (at GSX) e a Full-Scale 1 0 1 0 1 0 1 0 VIN (at GSX) e 0V 1 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 VIN (at GSX) ebFull-Scale 0 0 1 0 1 0 1 0 Note 1: Measured by extrapolation from the distortion test result at b 50 dBm0. Note 2: PPSRX, NPSRX, and CTR-X are measured with a b 50 dBm0 activation signal applied to VFXI a . Note 3: Devices are measured using C message weighted filter for m-Law and psophometric weighted filter for A-Law. 11 XL3057W SOP16 Applications Information POWER SUPPLIES While the pins of the XL3057W family are well protected against electrical misuse, it is recommended that the standard CMOS practice be followed, ensuring that ground is connected to the device before any other connections are made. In applications where the printed circuit board may be plugged into a ‘‘hot’’ socket with power and clocks already present, an extra long ground pin in the connector should be used. All ground connections to each device should meet at a common point as close as possible to the GNDA pin. This minimizes the interaction of ground return currents flowing through a common bus impedance. 0.1 mF supply decoupling capacitors should be connected from this common ground point to VCC and VBB, as close to the device as possible. For best performance, the ground point of each CODEC/ FILTER on a card should be connected to a common card ground in star formation, rather than via a ground bus. This common ground point should be decoupled to VCC and VBB with 10 mF capacitors. RECEIVE GAIN ADJUSTMENT For applications where a XL3057W family CODEC/filter re- ceive output must drive a 600X load, but a peak swing lower than g 2.5V is required, the receive gain can be easily ad- justed by inserting a matched T-pad or q-pad at the output. Table II lists the required resistor values for 600X termina- tions. As these are generally non-standard values, the equa- tions can be used to compute the attenuation of the closest practical set of resistors. It may be necessary to use un- equal values for the R1 or R4 arms of the attenuators to achieve a precise attenuation. Generally it is tolerable to allow a small deviation of the input impedance from nominal while still maintaining a good return loss. For example a 30 dB return loss against 600X is obtained if the output imped- ance of the attenuator is in the range 282X to 319X (as- suming a perfect transformer). Applications Information T-Pad Attenuator (Continued) TABLE II. Attentuator Tables for Z1 e Z2 e 300X (All Values in X) R1 e Z1 N2 a 1 2b1 #N #N R2 e 20Z1.Z2 Where: N e 0 J b 20Z1.Z2 #N N 2b1 J J N 2b1 POWER IN POWER OUT and Se 0Z2 Z1 Also: Z e 0ZSC # ZOC Where ZSC e impedance with short circuit termination and ZOC e impedance with open circuit termination q-Pad Attenuator R3 e 0 Z1.Z2 2 R3 e Z1 # # N2 b 1 N J N2 b 1 N2 b 2NS a 1 J 12 dB R1 R2 R3 R4 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 18 20 1.7 3.5 5.2 6.9 8.5 10.4 12.1 13.8 15.5 17.3 34.4 51.3 68 84 100 115 379 143 156 168 180 190 200 210 218 233 246 26k 13k 8.7k 6.5k 5.2k 4.4k 3.7k 3.3k 2.9k 2.6l 1.3k 850 650 494 402 380 284 244 211 184 161 142 125 110 98 77 61 3.5 6.9 10.4 13.8 17.3 21.3 24.2 27.7 31.1 34.6 70 107 144 183 224 269 317 370 427 490 550 635 720 816 924 1.17k 1.5k 52k 26k 17.4k 13k 10.5k 8.7k 7.5k 6.5k 5.8k 5.2k 2.6k 1.8k 1.3k 1.1k 900 785 698 630 527 535 500 473 450 430 413 386 366 XL3057W SOP16 Typical Synchronous Application XL3057W Note 1: XMIT gain e 20 c log # R1 a R2 R2 13 J where (R1 a R2) l 10 KX.