TLC2578IPWR


 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 D 14-Bit Resolution for TLC3574/78, 12-Bit for D D D D D D D D D D D D D D D TLC2574/2578 Maximum Throughput 200-KSPS Multiple Analog Inputs: − 8 Single-Ended Channels for TLC3578/2578 − 4 Single-Ended Channels for TLC3574/2574 Analog Input Range: ±10 V Pseudodifferential Analog Inputs SPI/DSP-Compatible Serial Interfaces With SCLK up to 25-MHz Built-In Conversion Clock and 8x FIFO Single 5-V Analog Supply; 3-/5-V Digital Supply Low-Power − 5.8 mA in Normal Operation − 20 µA in Power Down Programmable Autochannel Sweep and Repeat Hardware-Controlled, Programmable Sampling Period Hardware Default Configuration INL: TLC3574/78: ±1 LSB; TLC2574/78: ±0.5 LSB DNL: TLC3574/78: ±0.5 LSB; TLC2574/78: ±0.5 LSB SINAD: TLC3574/78: 79 dB; TLC2574/78: 72 dB THD: TLC3574/78: −82 dB; TLC2574/78: −82 dB TLC3578, TLC2578 DW OR PW PACKAGE (TOP VIEW) SCLK FS SDI EOC/INT SDO DGND DVDD CS A0 A1 A2 A3 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 CSTART AVDD AGND COMP REFM REFP AGND AVDD A7 A6 A5 A4 TLC3574, TLC2574 DW, N, OR PW PACKAGE (TOP VIEW) SCLK FS SDI EOC/INT SDO DGND DVDD CS A0 A1 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 CSTART AVDD AGND COMP REFM REFP AGND AVDD A3 A2 description The TLC3574, TLC3578, TLC2574, and TLC2578 are a family of high-performance, low-power, CMOS analog-to-digital converters (ADC). TLC3574/78 is a 14-bit ADC; TLC2574/78 is a 12-bit ADC. All parts operate from single 5-V analog power supply and 3-V to 5-V digital supply. The serial interface consists of four digital input [chip select (CS), frame sync (FS), serial input-output clock (SCLK), serial data input (SDI)], and a 3-state serial data output (SDO). CS (works as SS, slave select), SDI, SDO and SCLK form an SPI interface. FS, SDI, SDO, and SCLK form DSP interface. The frame sync signal (FS) indicates the start of a serial data frame being transferred. When multiple converters connect to one serial port of a DSP, CS works as the chip select to allow the host DSP to access the individual converter. CS can be tied to ground if only one converter is used. FS must be tied to DVDD if it is not used (such as in an SPI interface). When SDI is tied to DVDD, the device is set in hardware default mode after power on and no software configuration is required. In the simplest case, only three wires (SDO, SCLK, and CS or FS) are needed to interface with the host. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright  2000 − 2003, Texas Instruments Incorporated 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 description (continued) In addition to being a high-speed ADC with versatile control capability, these devices have an on-chip analog multiplexer (MUX) that can select any analog input or one of three self-test voltages. The sample-and-hold function is automatically started after the fourth SCLK (normal sampling) or can be controlled by a special pin, CSTART, to extend the sampling period (extended sampling). The normal sampling period can also be programmed as short sampling (12 SCLKs) or long sampling (44 SCLKs) to accommodate the faster SCLK operation popular among high-performance signal processors. The TLC3574/78 and TLC2574/78 are designed to operate with low-power consumption. The power saving feature is further enhanced with autopower-down mode and programmable conversion speeds. The conversion clock (internal OSC) is built in. The converter can also use an external SCLK as the conversion clock for maximum flexibility. The TLC3574/78 and TLC2574/78 are specified with bipolar input and a full scale range of ±10 V. AVAILABLE OPTIONS PACKAGED DEVICES TA 20-TSSOP (PW) −40°C to 85°C 20-SOIC (DW) 20-PDIP (N) 24-SOIC (DW) 24-TSSOP (PW) TLC2574IPW TLC2574IDW TLC2574IN TLC2578IDW TLC2578IPW TLC3574IPW TLC3574IDW TLC3574IN TLC3578IDW TLC3578IPW functional block diagram DVDD AVDD REFP COMP REFM X8† X4‡ A0 A0 A1 A1 A2 A2 A3 A3 X A4 X A5 X A6 X A7 SAR ADC Analog MUX Signal Scaling FIFO X8 OSC SDO Conversion Clock Command Decode CFR SDI CMR (4 MSBs) SCLK CS FS 4-Bit Counter Control Logic EOC/INT CSTART DGND AGND † TLC3578, TLC2578 ‡ TLC3574, TLC2574 NOTE: 4-Bit counter counts the CLOCK, SCLK. The CLOCK is gated in by CS falling edge if CS initiates the conversion operation cycle, or gated in by the rising edge of FS if FS initiates the operation cycle. SCLK is disabled for serial interface when CS is high. 2 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 equivalent input circuit VDD REFP Bipolar Signal Scaling MUX 3.94 kΩ Digital Input 1.5 kΩ 9.9 kΩ Ain Ron C(sample)= 30 pF 6.6 kΩ Equivalent Digital Input Circuit REFM Diode Turn on Voltage: 35 V Equivalent Analog Input Circuit Terminal Functions TERMINAL NO. NAME I/O DESCRIPTION 9 10 11 12 13 14 15 16 I Analog signal inputs. Analog input signals applied to these terminals are internally multiplexed. The driving source impedance should be less than or equal to 25 Ω for normal sampling. For larger source impedance, use the external hardware conversion start signal CSTART (the low time of CSTART controls the sampling period) or reduce the frequency of SCLK to increase the sampling time. 14, 18 18, 22 I Analog ground return for the internal circuitry. Unless otherwise noted, all analog voltage measurements are with respect to AGND. 13, 19 17, 23 I Analog supply voltage 17 21 I Internal compensation pin. Install compensation capacitors 0.1 µF between this pin and AGND. 8 8 I Chip select. When CS is high, SDO is in high-impedance state, SDI is ignored, and SCLK is disabled to clock data, but works as conversion clock source if programmed. The falling edge of CS input resets the internal 4-bit counter, enables SDI and SCLK, and removes SDO from high-impedance state. TLC3574 TLC2574 TLC3578 TLC2578 9 10 11 12 AGND AVDD COMP A0 A1 A2 A3 A0 A1 A2 A3 A4 A5 A6 A7 CS If FS is high at CS falling edge, CS falling edge initiates the operation cycle. CS works as slave select (SS) to provide an SPI interface. If FS is low at CS falling edge, FS rising edge initiates the operation cycle. CS can be used as chip select to allow host to access the individual converter. CSTART 20 24 I External sampling trigger signal, which initiates the sampling from a selected analog input channel when the device works in extended sampling mode (asynchronous sampling). A high-to-low transition starts the sampling of the analog input signal. A low-to-high transition puts the S/H in hold mode and starts the conversion. The low time of the CSTART signal controls the sampling period. CSTART signal must stay low long enough for proper sampling. CSTART must stay high long enough after the low-to-high transition for the conversion to finish maturely. The activation of CSTART is independent of SCLK and the level of CS and FS. However, the first CSTART cannot be issued before the rising edge of the eleventh SCLK. Tie this pin to DVDD if not used. DGND 6 6 I Digital ground return for the internal circuitry DVDD 7 7 I Digital supply voltage WWW.TI.COM 3 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 Terminal Functions (Continued) TERMINAL NO. I/O NAME TLC3574 TLC2574 TLC3578 TLC2578 EOC(INT) 4 4 O DESCRIPTION End of conversion (EOC) or interrupt to host processor (INT) EOC: used in conversion mode 00 only. EOC goes from high to low at the end of the sampling and remains low until the conversion is complete and data is ready. INT: Interrupt to the host processor. The falling edge of INT indicates data is ready for output. INT is cleared by the following CS↓, FS↑, or CSTART↓. FS 2 2 I Frame sync input from DSP. The rising edge of FS indicates the start of a serial data frame being transferred (coming into or being sent out of the device). If FS is low at the falling edge of CS, the rising edge of FS initiates the operation cycle, resets the internal 4-bit counter, and enables SDI, SDO, and SCLK. Tie this pin to DVDD if FS is not used to initiate the operation cycle. REFM 16 20 I External low reference input. Connect REFM to AGND. REFP 15 19 I External positive reference input. The range of maximum input voltage is determined by the difference between the voltage applied to this terminal and to the REFM terminal. Always install decoupling capacitors (10 µF in parallel with 0.1 µF) between REFP and REFM. SCLK 1 1 I Serial clock input from the host processor to clock in the input from SDI and clock out the output via SDO. It can also be used as the conversion clock source when the external conversion clock is selected (see Table 2). When CS is low, SCLK is enabled. When CS is high, SCLK is disabled for the data transfer, but can still work as the conversion clock source. SDI 3 3 I Serial data input. The first 4 MSBs, ID[15:12], are decoded as one 4-bit command. All trailing bits, except for the WRITE CFR command, are filled with zeros. The WRITE CFR command requires additional 12-bit data. The MSB of input data, ID(15), is latched at the first falling edge of SCLK following FS falling edge if FS starts the operation, or latched at the falling edge of first SCLK following CS falling edge when CS initiates the operation. The remaining input data (if any) is shifted in on the rising edge of SCLK and latched on the falling edge of SCLK. The input via SDI is ignored after the 4-bit counter counts to 16 (clock edges) or a low-to-high transition of CS, whichever happens first. Refer to the timing specification for the timing requirements. Tie SDI to DVDD if using hardware default mode (refer to Device Initialization). SDO 5 5 O The 3-state serial output for the A/D conversion result. All data bits are shifted out through SDO. SDO is in the high-impedance state when CS is high. SDO is released after a CS falling edge. The output format is MSB (OD15) first. When FS initiates the operation, the MSB of output via SDO, OD(15), is valid before the first falling edge of SCLK following the falling edge of FS. When CS initiates the operation, the MSB, OD(15), is valid before the first falling edge of SCLK following the CS falling edge. The remaining data bits (if any) are shifted out on the rising edge of SCLK and are valid before the falling edge of SCLK. Refer to the timing specification for the details. In select/conversion operation, the first 14 bits (for TLC3574/78) or the first 12 bits (for TLC2574/78) are the results from the previous conversion (data). In a READ FIFO operation, this data is from FIFO. In both cases, the last two bits (for TLC3574/78) or the last four bits (for TLC2574/78) are don’t care. In a WRITE operation, the output from SDO must be ignored. SDO goes into high-impedance state at the 16th falling edge of SCLK after the operation cycle is initiated. SDO is in high-impedance state during conversions in modes 01, 10, and 11. 4 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 absolute maximum ratings over operating free-air temperature (unless otherwise noted)† Supply voltage, GND to AVDD and DVDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to 6.5 V Analog input voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −17 V to 17 V Analog input current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mA MAX Reference input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AVDD + 0.3 V Digital input voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to DVDD + 0.3 V Operating virtual junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −40°C to 150°C Operating free-air temperature range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −40°C to 85°C Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C Lead temperature 1,6 mm (1.16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under electrical characteristics and timing characteristics is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. general electrical characteristics over recommended operating free-air temperature range, single-ended input, normal long sampling, 200 KSPS, AVDD = 5 V, VREFP = 4 V, VREFM = 0 V, SCLK frequency = 25 MHz, fixed channel at CONV mode 00, analog input signal source resistance = 25 Ω (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP† MAX UNIT Digital Input VIH High-level digital input voltage VIL Low-level digital input voltage IIH IIL High-level digital input current Low-level digital input current DVDD = 5 V 3.8 DVDD = 3 V 2.1 V DVDD = 5 V 0.8 DVDD = 3 V 0.6 VI = DVDD VI = DGND 0.005 −2.5 Input capacitance 2.5 µA µA −0.005 20 V 25 pF Digital Output VOH VOL IOZ High-level digital output at 30 pF load Io = −0.2 mA 4.2 DVDD = 3 V 2.4 V DVDD = 5 V Io = 0.8 mA Io = 50 µA 0.4 DVDD = 3 V Io = 0.8 mA Io = 50 µA 0.4 Low-level digital output at 30 pF load VO = DVDD VO = DGND Off-state output current (high-impedance state) DVDD = 5 V 0.1 V 0.1 0.02 CS = DVDD 1 µA −1 0.02 4.75 5 5.5 V 2.7 5 5.5 V 4.2 5 1.6 2.0 Power Supply AVDD DVDD ICC Supply voltage Power supply current ICC (autopwrdn): AVDD current AlCC DVDD current DlCC Autopower-down power supply current Operating temperature † All typical values are at TA = 25°C. Conversion clock is internal OSC, AVDD = 5.5 V − 4.5 V, CS = DGND, Excluding bipolar input biasing current For all digital inputs = DVDD or DGND, AVDD = 5.5 V, Excluding bipolar input biasing current, external reference mA SCLK OFF 20 SCLK ON 175 −40 WWW.TI.COM 230 85 µA °C 5 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 general electrical characteristics over recommended operating free-air temperature range, singleended input, normal long sampling, 200 KSPS, AVDD = 5 V, VREFP = 4 V, VREFM = 0 V, SCLK frequency = 25 MHz, fixed channel at CONV mode 00, analog input signal source resistance = 25 Ω (unless otherwise noted) TLC3574/78 and TLC2574/78 PARAMETER TEST CONDITIONS MIN Resolution TYP† MAX 14 UNIT bits Analog Input Voltage range −10 Selected channel at 10 V Selected analog input channel bias current 10 0.8 Selected channel at –10 V −1.6 V 1.6 mA −1.2 Impedance 10 kΩ Capacitance 30 pF Reference VREFP VREFM Positive reference voltage Negative reference voltage Input impedance 3.96 4 0 AGND No conversion (AVDD = 5V, CS= DVDD, SCLK=DGND) 100 Normal long sampling (AVDD = 5V, CS=DGND, SCLK = 25 MHz, External conversion clock) 8.3 Internal oscillation frequency Normal long sampling (AVDD = 5 V, CS = DGND, External conversion clock, SCLK = 25 MHz, VREF = 5 V) DVDD = 2.7 V – 5.5 V Internal OSC, 6.5 MHz minimum t(conv) Conversion time Conversion clock is external source, SCLK = 25 MHz (see Note 1) Acquisition time Normal short sampling Throughput rate (see Note 2) Normal long sampling, fixed channel in mode 00 or 01 V 12.5 0.4 kΩ 1.5 µA 0.6 mA 6.5 MHz TLC3574/78 2.785 TLC2574/78 2.015 TLC3574/78 2.895 TLC2574/78 2.095 1.2 200 V MΩ No conversion (AVDD = 5 V, SCLK = DGND, CS = DVDD) Reference current 4.04 µS S µS KSPS † All typical values are at TA = 25°C. NOTES: 1. Conversion time t(conv) is (18 × 4 × SCLK) + 15 ns for TLC3574/78. Conversion time is (13 × 4 × SCLK) + 15 ns for TLC2574/78. 2. This is for a fixed channel in conversion mode 00 or 01. When switching the channels, additional multiplexer setting time is required to overcome the memory effect of the charge redistribution DAC. 6 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 AC/DC performance over recommended operating free-air temperature range, single-ended input, normal long sampling, 200 KSPS, AVDD = 5 V, VREFP = 4 V, VREFM = 0 V, SCLK frequency = 25 MHz, fixed channel at CONV mode 00, analog input signal source resistance = 25 Ω (unless otherwise noted) TLC3574/78 DW and PW package device AC/DC performance MIN TYP† MAX UNIT See Note 3 −1.5 ±1 1.5 LSB PARAMETER TEST CONDITIONS DC Accuracy—Normal Long Sampling EL ED Integral linearity error −1 ±0.5 1 LSB EO EFS(+) Bipolar zero error See Note 4 −0.30 ±0.08 0.36 %FS Positive full scale error Differential linearity error See Note 4 −0.55 ±0.04 0.61 %FS EFS(−) Negative full scale error DC Accuracy—Normal Short Sampling See Note 4 −0.30 ±0.13 0.79 %FS EL ED Integral linearity error See Note 3 EO EFS(+) Bipolar zero error Positive full scale error ±1 LSB ±0.5 LSB See Note 4 ±0.08 %FS See Note 4 ±0.04 %FS EFS(−) Negative full scale error See Note 4 AC Accuracy (see Note 3)—Normal Long Sampling ±0.13 %FS Differential linearity error SINAD Signal-to-noise ratio + distortion fi = 20 kHz fi = 100 kHz THD Total harmonic distortion fi = 20 kHz fi = 100 kHz SNR Signal-to-noise ratio fi = 20 kHz fi = 100 kHz 78 ENOB Effective number of bits fi = 20 kHz fi = 100 kHz 12.3 SFDR Spurious free dynamic range fi = 20 kHz fi = 100 kHz 78 Channel-to-channel isolation Fixed channel in conversion mode 00, fi = 35 kHz, See Notes 2 and 5 Analog input bandwidth 76 79 dB 75 −82 −78 80 78 12.8 12.2 84 79 −77 dB dB Bits dB 81 dB Full power bandwidth, −3 dB 1 MHz Full power bandwidth, −1 dB 700 kHz † All typical values are at TA = 25°C. NOTES: 2. This is for a fixed channel in conversion mode 00 or 01. When switching the channels, additional multiplexer setting time is required to overcome the memory effect of the charge redistribution DAC. 3. Linear error is the maximum deviation from the best fit straight line through the A/D transfer characteristics. 4. Bipolar zero error is the difference between 10000000000000 and the converted output for zero input voltage; positive full-scale error is the difference between 11111111111111 and the converted output for positive full-scale input voltage (10 V); negative full-scale error is the difference between 00000000000000 and the converted output for negative full-scale input voltage (−10 V). 5. It is measured by applying a full-scale of 35 kHz signal to other channels and determining how much the signal is attenuated in the channel of interest. The converter samples this examined channel continuously. The channel-to-channel isolation is degraded if the converter samples different channels alternately. WWW.TI.COM 7 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TLC3574/78 DW and PW package device AC/DC performance (continued) PARAMETER TEST CONDITIONS MIN TYP† MAX UNIT AC Accuracy—Normal Short Sampling SINAD Signal-to-noise ratio + distortion fi = 20 kHz fi = 100 kHz 79 THD Total harmonic distortion fi = 20 kHz fi = 100 kHz −82 SNR Signal-to-noise ratio fi = 20 kHz fi = 100 kHz 80 ENOB Effective number of bits fi = 20 kHz fi = 100 kHz 12.8 SFDR Spurious free dynamic range fi = 20 kHz fi = 100 kHz 84 Channel-to-channel isolation Fixed channel in conversion mode 00, fi= 35 kHz, See Notes 2 and 5 Analog input bandwidth 75 −78 78 12.2 79 dB dB dB Bits dB 81 dB Full power bandwidth, −3 dB 1 MHz Full power bandwidth, −1 dB 700 kHz † All typical values are at TA = 25°C. NOTES: 2. This is for a fixed channel in conversion mode 00 or 01. When switching the channels, additional multiplexer setting time is required to overcome the memory effect of the charge redistribution DAC. 5. It is measured by applying a full-scale of 35 kHz signal to other channels and determining how much the signal is attenuated in the channel of interest. The converter samples this examined channel continuously. The channel-to-channel isolation is degraded if the converter samples different channels alternately. 8 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TLC3574I N package device AC/DC performance PARAMETER TEST CONDITIONS TYP† MAX UNIT −1.5 ±1 1.5 LSB −1 ±0.8 1.5 LSB MIN DC Accuracy—Normal Long Sampling EL ED Integral linearity error See Note 3 EO EFS(+) Bipolar zero error See Note 4 −0.30 ±0.08 0.36 %FS Positive full scale error Differential linearity error See Note 4 −0.55 ±0.04 0.61 %FS EFS(−) Negative full scale error DC Accuracy—Normal Short Sampling See Note 4 −0.30 ±0.13 0.79 %FS EL ED Integral linearity error See Note 3 ±1.8 ±0.8 LSB EO EFS(+) Bipolar zero error See Note 4 ±0.08 %FS Positive full-scale error See Note 4 ±0.04 %FS EFS(−) Negative full-scale error See Note 4 AC Accuracy (see Note 3)—Normal Long Sampling ±0.13 %FS Differential linearity error SINAD Signal-to-noise ratio + distortion fi = 20 kHz fi = 100 kHz THD Total harmonic distortion fi = 20 kHz fi = 100 kHz SNR Signal-to-noise ratio fi = 20 kHz fi = 100 kHz 78 ENOB Effective number of bits fi = 20 kHz fi = 100 kHz 12.2 SFDR Spurious free dynamic range fi = 20 kHz fi = 100 kHz 78 Channel-to-channel isolation Fixed channel in conversion mode 00, fi = 35 kHz, See Notes 2 and 5 Analog input bandwidth 75 LSB 78 dB 75 −82 −75 80 76 12.7 12.2 83 75 −77 dB dB Bits dB 81 dB Full power bandwidth, −3 dB 1 MHz Full power bandwidth, −1 dB 700 kHz † All typical values are at TA = 25°C. NOTES: 2. This is for a fixed channel in conversion mode 00 or 01. When switching the channels, additional multiplexer setting time is required to overcome the memory effect of the charge redistribution DAC. 3. Linear error is the maximum deviation from the best fit straight line through the A/D transfer characteristics. 4. Bipolar zero error is the difference between 10000000000000 and the converted output for zero input voltage; positive full-scale error is the difference between 11111111111111 and the converted output for positive full-scale input voltage (10 V); negative full-scale error is the difference between 00000000000000 and the converted output for negative full-scale input voltage (−10 V). 5. It is measured by applying a full-scale of 35 kHz signal to other channels and determining how much the signal is attenuated in the channel of interest. The converter samples this examined channel continuously. The channel-to-channel isolation is degraded if the converter samples different channels alternately. WWW.TI.COM 9 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TLC3574I N package device AC/DC performance (continued) PARAMETER TEST CONDITIONS MIN TYP† MAX UNIT AC Accuracy—Normal Short Sampling SINAD Signal-to-noise ratio + distortion fi = 20 kHz fi = 100 kHz 76 THD Total harmonic distortion fi = 20 kHz fi = 100 kHz −81 SNR Signal-to-noise ratio fi = 20 kHz fi = 100 kHz 78 ENOB Effective number of bits fi = 20 kHz fi = 100 kHz 12.3 SFDR Spurious free dynamic range fi = 20 kHz fi = 100 kHz 83 Channel-to-channel isolation Fixed channel in conversion mode 00, fi= 35 kHz, See Notes 2 and 5 Analog input bandwidth 70 −74 75 11.3 75 dB dB dB Bits dB 81 dB Full power bandwidth, −3 dB 1 MHz Full power bandwidth, −1 dB 700 kHz † All typical values are at TA = 25°C. NOTES: 2. This is for a fixed channel in conversion mode 00 or 01. When switching the channels, additional multiplexer setting time is required to overcome the memory effect of the charge redistribution DAC. 5. It is measured by applying a full-scale of 35 kHz signal to other channels and determining how much the signal is attenuated in the channel of interest. The converter samples this examined channel continuously. The channel-to-channel isolation is degraded if the converter samples different channels alternately. 10 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TLC2574/78 DW and PW package devices AC/DC performance MIN TYP† MAX UNIT See Note 6 −1 ±0.5 1 LSB PARAMETER TEST CONDITIONS DC Accuracy EL ED Integral linearity error −1 ±0.5 1 LSB EO EFS(+) Bipolar zero error See Note 7 −0.30 ±0.08 0.36 %FS Positive full scale error See Note 7 −0.55 ±0.04 0.61 %FS See Note 7 −0.30 ±0.13 0.79 %FS 70 72 Differential linearity error EFS(−) Negative full scale error AC Accuracy SINAD Signal-to-noise ratio + distortion THD Total harmonic distortion SNR Signal-to-noise ratio ENOB Effective number of bits SFDR Spurious free dynamic range Analog input bandwidth Channel-to-channel Isolation fi = 20 kHz fi = 100 kHz fi = 20 kHz dB 70 −82 fi = 100 kHz fi= 20 kHz −80 71 fi = 100 kHz fi = 20 kHz 11.3 dB 11.7 11.3 78 dB 72 71 fi = 100 kHz fi = 20 kHz −76 Bits 83 dB fi = 100 kHz Full power bandwidth, −3 dB 80 1 MHz Full power bandwidth, −1 dB 700 kHz 81 dB Fixed channel in conversion mode 00, fi = 35 kHz, See Note 8 † All typical values are at TA = 25°C. NOTES: 6. Linear error is the maximum deviation from the best fit straight line through the A/D transfer characteristics. 7. Bipolar zero error is the difference between 100000000000 and the converted output for zero input voltage; positive full-scale error is the difference between 111111111111 and the converted output for positive full-scale input voltage (10 V); negative full-scale error is the difference between 000000000000 and the converted output for negative full-scale input voltage (−10 V). 8. It is measured by applying a full-scale of 35 kHz signal to other channels and determining how much the signal is attenuated in the channel of interest. The converter samples this examined channel continuously. The channel-to-channel isolation is degraded if the converter samples different channels alternately. WWW.TI.COM 11 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TLC2574I N package device AC/DC performance MIN TYP† MAX UNIT see Note 6 −1 ±0.7 1 LSB PARAMETER TEST CONDITIONS DC Accuracy EL ED Integral linearity error −1 ±0.7 1 LSB EO EFS(+) Bipolar zero error see Note 7 −0.30 ±0.08 0.36 %FS Positive full-scale error see Note 7 −0.55 ±0.04 0.61 %FS see Note 7 −0.30 ±0.13 0.79 %FS 70 72 Differential linearity error EFS(−) Negative full-scale error AC Accuracy SINAD Signal-to-noise + distortion THD Total harmonic distortion SNR Signal-to-noise ratio ENOB Effective number of bits SFDR Spurious free dynamic range Analog input bandwidth Channel-to-channel Isolation fi = 20 kHz fi = 100 kHz fi = 20 kHz dB 70 −82 fi = 100 kHz fi= 20 kHz −75 70 fi = 100 kHz fi = 20 kHz 11.3 dB 11.7 11.3 77 dB 72 71 fi = 100 kHz fi = 20 kHz −76 Bits 83 dB fi = 100 kHz Full power bandwidth, −3 dB 75 1 MHz Full power bandwidth, −1 dB 700 kHz 81 dB Fixed channel in conversion mode 00, fi = 35 kHz, See Note 8 † All typical values are at TA = 25°C. NOTES: 6. Linear error is the maximum deviation from the best fit straight line through the A/D transfer characteristics. 7. Bipolar zero error is the difference between 100000000000 and the converted output for zero input voltage; positive full-scale error is the difference between 111111111111 and the converted output for positive full-scale input voltage (10 V); negative full-scale error is the difference between 000000000000 and the converted output for negative full-scale input voltage (−10 V). 8. It is measured by applying a full-scale of 35 kHz signal to other channels and determining how much the signal is attenuated in the channel of interest. The converter samples this examined channel continuously. The channel-to-channel isolation is degraded if the converter samples different channels alternately. 12 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 timing requirements over recommended operating free-air temperature range, AVDD = 5 V, DVDD = 5 V, VREFP = 4 V, VREFM = 0 V, SCLK frequency = 25 MHz (unless otherwise noted) SCLK, SDI, SDO, EOC and INT PARAMETERS tc(1) Cycle time of SCLK, 25 pF load (see Note 10) tw(1) Pulse width of SCLK High, at 25-pF load MIN DVDD = 2.7 V DVDD = 5 V TYP MAX 100 UNIT ns 40 40% 60% DVDD = 5 V DVDD = 2.7 V 6 tc(1) tr(1) Rise time for INT and EOC, at 10-pF load tf(1) Fall time for INT and EOC, at 10-pF load tsu(1) th(1) DVDD = 5 V DVDD = 2.7 V Setup time, new SDI valid (reaches 90% final level) before the falling edge of SCLK, at 25-pF load 6 − ns Hold time, old SDI hold (reaches 10% of old data level) after falling edge of SCLK, at 25-pF load 0 − ns 0 10 0 23 td(1) Delay time, new SDO valid (reaches 90% of final level) after SCLK rising edge, at 10-pF load (see Note 11) 10 6 10 DVDD = 5 V DVDD = 2.7 V ns ns ns th(2) td(2) Hold time, old SDO hold (reaches 10% of old data level) after SCLK rising edge, at 10-pF load 0 − ns Delay time, delay from the falling edge of 16th SCLK to EOC falling edge, normal sampling, at 10-pF load 0 6 ns td(3) Delay time, delay from the falling edge of 16th SCLK to INT falling edge, at 10-pF load (see Notes 11 and 12) t(conv) t(conv)+6 ns NOTES: 9. The minimum pulse width of SCLK high and low is 12.5 ns. 10. Specified by design 11. For normal short sampling, td(3) is the delay from the falling edge of 16th SCLK to the falling edge of INT. For normal long sampling, td(3) is the delay from the falling edge of 48th SCLK to the falling edge of INT. Conversion time, t(conv), is equal to 18 × OSC +15 ns (for TLC3574 and TLC3578) or 13 × OSC + 15 ns (for TLC2574 and TLC2578) when using internal OSC as conversion clock, or 72 × tc(1) + 15 ns (for TLC3574 and TLC3578) or 52 × tc(1) + 15 ns (for TLC2574 and TLC2578) when external SCLK is conversion clock source. VIH 90% 50% 10% CS VIL tc(1) tw(1) 1 SCLK 16 th(1) tsu(1) SDI Don’t Care ID15 ID1 ID0 Don’t Care td(1) th(2) SDO Hi-Z OD15 OD1 Hi-Z OD0 td(2) † tr(1) EOC tf(1) OR td(3) ‡ INT tf(1) tr(1) † For normal long sampling, td(2) is the delay time of EOC low after the falling edge of 48th SCLK. ‡ For normal long sampling, td(3) is the delay time of INT low after the falling edge of 48th SCLK. −−−− The dotted line means signal may or may not exist, depending on application. It must be ignored. Normal sampling mode, CS initiatesthe conversion, FS must be tied to high. When CS is high, SDO is in Hi-Z, all inputs (FS, SCLK, SDI) are inactive and are ignored. Figure 1. Critical Timing for SCLK, SDI, SDO, EOC and INT WWW.TI.COM 13 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 timing requirements over recommended operating free-air temperature range, AVDD = 5 V, DVDD = 5 V, VREFP = 4 V, VREFM = 0 V, SCLK frequency = 25 MHz (unless otherwise noted) (continued) CS trigger PARAMETERS MIN TYP MAX UNIT tsu(2) Setup time, CS falling edge before SCLK rising edge, at 25-pF load 12 ns td(4) Delay time, delay time from the falling edge of 16th SCLK to CS rising edge, at 25 pF load (see Note 12) 5 ns tw(2) Pulse width of CS high, at 25-pF load 1 td(5) Delay time, delay from CS falling edge to MSB of SDO valid (reaches 90% final level), at 10 pF load td(6) Delay time, delay from CS rising edge to SDO 3-state, at 10-pF load td(7) Delay time, delay from CS falling edge to INT rising edge, at 10-pF load DVDD = 5 V 0 DVDD = 2.7 V tc(1) 0 12 30† ns 0 6 ns DVDD = 5 V 0 DVDD = 2.7 V 0 6 † 16 ns † Specified by design NOTE 12: For normal short sampling, td(4) is the delay time from the falling edge of 16th SCLK to CS rising edge. For normal long sampling, td(4) is the delay time from the falling edge of 48th SCLK to CS rising edge. VIH VIL CS tsu(2) SCLK SDI SDO td(4) 1 Don’t Care Hi-Z tw(2) 16 ID1 ID0 Don’t Care OD15 OD1 OD0 Hi-Z ID15 Don’t Care td(6) td(5) OD15 OD7 Hi-Z EOC OR td(7) INT −−−− The dotted line means signal may or may not exist, depending on application. It must be ignored. Normal sampling mode, CS initiates the conversion, FS must be tied to high. When CS is high, SDO is in Hi-Z, all inputs (FS, SCLK, SDI) are inactive and are ignored. Figure 2. Critical Timing for CS Trigger 14 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 timing requirements over recommended operating free-air temperature range, AVDD = 5 V, DVDD = 5 V, VREFP = 4 V, VREFM = 0 V, SCLK frequency = 25 MHz (unless otherwise noted) (continued) FS trigger PARAMETERS MIN td(8) tsu(3) Delay time, delay from CS falling edge to FS rising edge at 25-pF load tw(3) Pulse width of FS high, at 25-pF load TYP MAX tc(1) 0.5×tc(1)+ 5 1.25×tc(1) 0.5 Setup time, FS rising edge before SCLK falling edge at 25-pF load 0.25×tc(1) 0.75×tc(1) DVDD = 5 V td(9) Delay time, delay from FS rising edge to MSB of SDO valid (reaches 90% final level), at 10-pF load td(10) Delay time, delay from FS rising edge to next FS rising edge, at 25-pF load td(11) Delay time, delay from FS rising edge to INT rising edge, at 10-pF load UNIT tc(1) ns ns 26 30† DVDD = 2.7 V Required sampling time + conversion time ns ns DVDD = 5 V 0 6 DVDD = 2.7 V 0 16† ns † Specified by design VIH VIL td(10) CS td(8) tw(3) FS tsu(3) SCLK SDI Don’t Care 16 1 ID15 ID1 ID0 Don’t Care ID15 Don’t Care td(9) SDO Hi-Z OD15 OD1 OD0 Hi-Z OD15 Don’t Care VOH EOC OR td(11) VOH INT −−−− The dotted line means signal may or may not exist, depending on application. It must be ignored. Normal sampling mode, FS initiates the conversion, CS can be tied to low. When CS is high, SDO is in Hi-Z, all inputs (FS, SCLK, SDI) are inactive and are ignored. Figure 3. Critical Timing for FS Trigger WWW.TI.COM 15 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 timing requirements over recommended operating free-air temperature range, AVDD = 5 V, DVDD = 5 V, VREFP = 4 V, VREFM = 0 V, SCLK frequency = 25 MHz (unless otherwise noted) (continued) CSTART trigger PARAMETERS MIN td(12) Delay time, delay from CSTART rising edge to EOC falling edge, at 10-pF load tw(4) Pulse width of CSTART low, at 25-pF load (see Note 13) td(13) 0 TYP MAX 15 21 UNIT ns t(sample_reg)+0.4 µs Delay time, delay from CSTART rising edge to CSTART falling edge, at 25-pF load (see Note 13 and 14) t(conv)+15 ns td(14) Delay time, delay from CSTART rising edge to INT falling edge, at 10-pF load (see Note 13 and 14) t(conv)+15 td(15) Delay time, delay from CSTART falling edge to INT rising edge, at 10-pF load 0 t(conv)+21 ns 6 ns NOTES: 13. The pulse width of the CSTART must be not less than the required sampling time. The delay from CSTART rising edge to following CSTART falling edge must be not less than the required conversion time. The delay from CSTART rising edge to the INT falling edge is equal to the conversion time. 14. The maximum rate of SCLK is 25 MHz for normal long sampling and 10 MHz for normal short sampling. tw(4) td(13) CSTART t(conv) td(12) EOC td(15) OR td(14) INT Figure 4. Critical Timing for Extended Sampling (CSTART Trigger) 16 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 circuit description converter The converters include a successive-approximation ADC utilizing a charge redistribution DAC. Figure 5 shows a simplified block diagram of the ADC. The sampling capacitor acquires the signal on Ain during the sampling period. When the conversion process starts, the control logic directs the charge redistribution DAC to add and subtract fixed amounts of charge from the sampling capacitor to bring the comparator into a balanced condition. When balanced, the conversion is complete and the ADC output code is generated. Charge Redistribution DAC _ Ain C(sample) Control Logic + ADC Code REFM Figure 5. Simplified Block Diagram of the Successive-Approximation System analog input range and internal test voltages TLC3578 and TLC2578 have 8 analog inputs (TLC3574 and TLC2574 have 4) and three test voltages. The inputs are selected by the analog multiplexer according to the command entered (see Table 1). The input multiplexer is a break-before-make type to reduce input-to-input noise injection resulting from channel switching. All converters are specified for bipolar input range of ±10 V. The input signal is scaled to 0–4 V at the SAR ADC input via the bipolar scaling circuit (see the functional block diagram and the equivalent analog input circuit): –10 V to 0 V, 10 V to 4 V, and 0 V to 2 V. analog input mode Two input signal modes can be selected: single-ended input and pseudodifferential input. Charge Redistribution DAC S1 Ain(+) _ Ain(−) + REFM Control Logic ADC Code When sampling, S1 is closed and S2 connects to Ain(−). During conversion, S1 is open and S2 connects to REFM. Figure 6. Simplified Pseudodifferential Input Circuit Pseudodifferential input refers to the negative input, Ain(−). Its voltage is limited in magnitude to ±1 V. The input frequency limit of Ain(−) is the same as the positive input Ain(+). This mode is normally used for ground noise rejection or dc offset. WWW.TI.COM 17 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 analog input mode (continued) When pseudodifferential mode is selected, only two analog input channel pairs are available for the TLC3574 and TLC2574 and four channel pairs for the TLC3578 and TLC2578, because half the inputs are used as the negative input. Single Ended X8† X4‡ A0 A0 A1 A1 A2 A2 A3 A3 X A4 X A5 X A6 X A7 Pseudodifferential SAR ADC Analog MUX X8† A0(+) A1(−) A2(+) A3(−) A4(+) A5(−) A6(+) A7(−) Pair A Pair B X4‡ A0(+) Pair A A1(−) A2(+) Pair B A3(−) Pair C SAR ADC Analog MUX Pair D † TLC3578 and TLC2578 ‡ TLC3574 and TLC2574 Figure 7. Pin Assignment of Single-Ended Input vs Pseudodifferential Input reference voltage The external reference is applied to the reference-input pins (REFP and REFM). REFM should connect to analog ground. REFP is 4 V. Install decoupling capacitors (10 µF in parallel with 0.1 µF) between REFP and REFM, and compensation capacitors (0.1 µF) between COMP and AGND. ideal conversion characteristics Bipolar Analog Input Voltage −9.99756 V −9.99878 V VBZS = 0.0 V −0.61 mV 0.61 mV 1LSB = 1.22 mV 9.99756 V −9.99939 V VFS+ = 10 V 18 2s Complement BTC 01111111111111 Binary BOB 11111111111111 01111111111110 11111111111110 16383 01111111111101 11111111111101 16382 16381 00000000000001 10000000000001 8193 00000000000000 10000000000000 8192 11111111111111 01111111111111 8191 10000000000010 00000000000010 2 10000000000001 00000000000001 1 10000000000000 00000000000000 0 WWW.TI.COM Step Digital Output Code VFS− = −10 V 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 circuit description (continued) data format INPUT DATA FORMAT (BINARY) MSB LSB ID[15:12] ID[11:0] Command Configuration data field or filled with zeros OUTPUT DATA FORMAT (READ CONVERSION/FIFO) TLC3574 and TLC3578 TLC2574 and TLC2578 MSB LSB MSB LSB OD[15:2] OD[1:0] OD[15:4] OD[3:0] Conversion result Don’t Care Conversion result Don’t Care 14-BIT (TLC3574/78) 12-BIT (TLC2574/78) Bipolar Input, Offset Binary: (BOB) Negative full scale code = VFS− = 0000h, Vcode = −10 V Midscale code = VBZS = 2000h, Vcode = 0 V Positive full scale code = VFS+ = 3FFFh, Vcode = 10 V − 1 LSB Bipolar Input, Binary 2s Complement: (BTC) Negative full scale code = VFS− = 2000 h, Vcode = −10 V Midscale code = VBZS = 0000h, Vcode = 0 V Positive full scale code = VFS+ = 1FFFh, Vocde = 10 V − 1 LSB Bipolar Offset Binary Output: (BOB) Negative full scale code = 000h, Vcode = −10 V Midscale code = 800h, Vcode = 0 V Positive full scale code = FFFh, Vcode = 10 V − 1 LSB Bipolar Input, Binary 2s Complement: (BTC) Negative full scale code = 800 h, Vcode = −10 V Midscale code = 000h, Vcode = 0 V Positive full scale code = 7FFh, Vocde = 10 V − 1 LSB operation description The converter samples the selected analog input signal, then converts the sample into digital output according to the selected output format. The converter has four digital input pins (SDI, SCLK, CS, and FS) and one digital output pin (SDO) to communicate with the host device. SDI is a serial data input pin, SDO is a serial data output pin, and SCLK is a serial clock from host device. This clock is used to clock the serial data transfer. It can also be used as conversion clock source (see Table 2). CS and FS are used to start the operation. The converter has a CSTART pin for external hardware sampling and conversion trigger, and INT/EOC for interrupt purpose. device initialization After power on, the status of EOC/INT is initially high, and the input data register is set to all zeros. The device must be initialized before starting conversion. The initialization procedure depends on the working mode. The first conversion result must be ignored after power on. Hardware Default Mode: Nonprogrammed mode, default. After power on, two consecutive active cycles initiated by CS or FS put the device into hardware default mode if SDI is tied to DVDD. Each of these cycles must last 16 SCLK at least. These cycles initialize the converter and load CFR register with 800h (bipolar offset binary output code, normal long sampling, internal OSC, single-ended input, one-shot conversion mode, and EOC/INT pin as INT). No additional software configuration is required. Software Programmed Mode: Programmed. If the converter needs to be configured, The host must write A000H into converters first after power on, then performs the WRITE CFR operation to configure the device. start of operation cycle Each operation consists of several actions that the converter takes according to the command from the host. The operation cycle includes three periods: command period, sampling period, and conversion period. In the command period, the device decodes the command from host. In the sampling period, the device samples the selected analog signal according to the command. In the conversion period, the sample of the analog signal is converted to digital format. The operation cycle starts from the command period, which is followed by one or several sampling and conversion periods (depending on the setting), and finishes at the end of last conversion period. The operation is initiated by the falling edge of CS or the rising edge of FS. WWW.TI.COM 19 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 start of operation cycle (continued) CS initiates the operation: If FS is high at the falling edge of CS, the falling edge of CS initiates the operation. When CS is high, SDO is in high-impedance state, the signals on SDI are ignored, and SCLK is disabled to clock the serial data. The falling edge of CS resets the internal 4-bit counter and enables SDO, SDI, and SCLK. The MSB of the input data via SDI, ID(15), is latched at the first falling edge of SCLK following the falling edge of CS. The MSB of output data from SDO, OD(15), is valid before this SCLK falling edge. This mode works as an SPI interface when CS is used as SLAVE SELECT (SS). It also can be used as normal DSP interface if CS connects to the frame sync output of the host DSP. FS must be tied to high in this mode. FS initiates the operation: If FS is low at the falling edge of CS, the rising edge of FS initiates the operation. It resets the internal 4-bit counter, and enables SDI, SDO, and SCLK. The ID(15) is latched at the first falling edge of SCLK following the falling edge of FS. OD(15) is valid before this falling edge of SCLK. This mode is used to interface the converter with a serial port of the host DSP. The FS of the device is connected to the frame sync of the host DSP. When several devices are connected to one DSP serial port, CS is used as chip select to allow the host DSP to access each device individually. If only one converter is used, CS can be tied to low. After the initiation, the remaining SDI data bits (if any) are shifted in and the remaining bits of SDO (if any) are shifted out at the rising edge of SCLK. The input data are latched at the falling edge of SCLK, and the output data are valid before the falling edge of SCLK. After the 4-bit counter reaches 16, the SDO goes to high-impedance state. The output data from SDO is the previous conversion result in one shot conversion mode, or the contents in the top of FIFO when FIFO is used (refer to Figure 20). command period After the rising edge of FS (FS triggers the operation) or the falling edge of CS (CS triggers the operation), SDI, SDO, and SCLK are enabled. The first four SCLK clocks form the command period. The four MSBs of input data, ID[15:12], are shifted in and decoded. These bits represent one of the 4-bit commands from the host, which defines the required operation (see Table 1). The four MSB of output, OD[15:12], are also shifted out via SDO during this period. The commands are SELECT/CONVERSION, WRITE CFR, FIFO READ, and HARDWARE DEFAULT. The SELECT/CONVERSION command includes SELECT ANALOG INPUT and SELECT TEST commands. All cause a select/conversion operation. They select the analog signal being converted, and start the sampling/conversion process after the selection. WRITE CFR causes the configuration operation, which writes the device configuration information into CFR register. FIFO READ reads the contents in FIFO. Hardware default mode sets the device into the hardware default mode. After the command period, the remaining 12 bits of SDI are written into the CFR register to configure the device if the command is WRITE CFR. Otherwise, these bits are ignored. The configuration is retained in the autopower-down state. If the SCLK stops (while CS remains low) after the first eight bits are entered, the next eight bits can be entered after the SCLK resumes. The data on SDI are ignored after the 4-bit counter counts to 16 (falling edge of SCLK) or the low-to-high transition of CS, whichever happens first. The remaining 12 bits of output data are shifted out from SDO if the command is SELECT/CONVERSION or FIFO READ. Otherwise, the data on SDO must be ignored. In any case, the SDO goes into high-impedance state after the 4-bit counter counts to 16 (falling edge of SCLK) or the low-to-high transition of CS, whichever happens first. 20 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 command period (continued) Table 1. Command Set (CMR) SDI Bit D[15:12] TLC3578 / 2578 COMMAND TLC3574 / 2574 COMMAND BINARY HEX 0000b 0h SELECT analog input channel 0 SELECT analog input channel 0 0001b 1h SELECT analog input channel 1 SELECT analog input channel 1 0010b 2h SELECT analog input channel 2 SELECT analog input channel 2 0011b 3h SELECT analog input channel 3 SELECT analog input channel 3 0100b 4h SELECT analog input channel 4 SELECT analog input channel 0 0101b 5h SELECT analog input channel 5 SELECT analog input channel 1 0110b 6h SELECT analog input channel 6 SELECT analog input channel 2 0111b 7h SELECT analog input channel 7 SELECT analog input channel 3 1000b 8h Reserved 1001b 9h Reserved 1010b Ah WRITE CFR, the last 12 bits of SDI are written into CFR. This command resets FIFO. 1011b Bh SELECT TEST, voltage = (REFP+REFM)/2 (see Note 15) 1100b Ch SELECT TEST, voltage = REFM (see Note 16) 1101b Dh SELECT TEST, voltage = REFP (see Note 17) 1110b Eh FIFO READ, FIFO contents is shown on SDO; (see Note 18) 1111b Fh HARDWARE DEFAULT mode, CFR is loaded with 800h NOTES: 15. 16. 17. 18. The output code = mid-scale code + bipolar zero error The output code = negative full-scale code + negative full-scale error The output code = positive full-scale code + positive full-scale error The TLC3574 and TLC3578, OD [15:2] is conversion result, OD [1:0] don’t care The TLC2574 and TLC2578, OD [15:4] is conversion result, OD [3:0] don’t care WWW.TI.COM 21 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 detailed description (continued) Table 2. Configuration Register (CFR) Bit Definition SDI BIT DEFINITION D11 Always 1. Otherwise the performance is degraded. D10 Conversion output code format select: 0: BOB (bipolar offset binary); D9 1: BTC (binary 2s complement) Sample period select for normal sampling. Don’t care in extended sampling. 0: Long sampling (4x) 44 SCLKs; 1: Short sampling 12 SCLKs D8 Conversion clock source select: 0: Conversion clock = Internal OSC; 1: Conversion clock = SCLK/4 D7 Input mode select: 0: Single-ended; 1: Pseudodifferential. Pin configuration shown below. Pin Configuration of TLC3578 and TLC2578 Pin Configuration of TLC3574 and TLC2574 Pin No. Single-ended Pseudodifferential polarity Pin No. Single-ended Pseudodifferential polarity 9 10 A0 A1 Plus Minus Pair A 9 10 A0 A1 PLUS MINUS Pair A 11 12 A2 A3 Plus Minus Pair B 11 12 A2 A3 PLUS MINUS Pair B 13 14 A4 A5 Plus Minus Pair C 15 16 A6 A7 Plus Minus Pair D D[6:5] Conversion mode select 00: One shot mode 01: Repeat mode 10: Sweep mode 11: Repeat sweep mode. D[4:3] Sweep auto sequence select (Note: These bits only take effect in conversion mode 10 and 11.) TLC3578 and TLC2578 D2 D[1:0] TLC3574 and TLC2574 Single-ended (by ch) Pseudodifferential (by pair) Single-ended (by ch) Pseudodifferential (by pair) 00: 0−1−2−3−4−5−6−7 01: 0−2−4−6−0−2−4−6 10: 0−0−2−2−4−4−6−6 11: 0−2−0−2−0−2−0−2 00: N/A 01: A−B−C−D−A−B−C−D 10: A−A−B−B−C−C−D−D 11: A−B−A−B−A−B−A−B 00: 0−1−2−3−0−1−2−3 01: 0−2−0−2−0−2−0−2 10: 0−0−1−1−2−2−3−3 11: 0−0−0−0−2−2−2−2 00: N/A 01: A−B−A−B−A−B−A−B 10: N/A 11: A−A−A−A−B−B−B−B EOC/INT pin function select 0: Pin used as INT 1: Pin used as EOC ( for mode 00 only) FIFO trigger level (sweep sequence length). Don’t care in one shot mode. 00: Full (INT generated after FIFO Level 7 filled) 01: 3/4 (INT generated after FIFO Level 5 filled) 10: 1/2 (INT generated after FIFO Level 3 filled) 11: 1/4 (INT generated after FIFO Level 1 filled) sampling period The sampling period follows the command period. The selected signal is sampled during this time. The device has three different sampling modes: normal short mode, normal long mode, and extended mode. Normal Short Sampling Mode: Sampling time is controlled by the SCLK and lasts 12 SCLK periods. At the end of sampling, the converter automatically starts the conversion period. After the configuration, the normal sampling starts automatically after the falling edge of fourth SCLK that follows the falling edge of CS if CS triggers the operation, or follows the rising edge of FS if FS initiates the operation, except the FIFO READ and WRITE CFR commands. 22 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 sampling period (continued) Normal Long Sampling Mode: It is the same as normal short sampling, except that it lasts 44 SCLKs periods to complete the sampling. Extended Sampling Mode: The external signal, CSTART, triggers sampling and conversion. SCLK is not used for sampling. SCLK is also not needed for conversion if the internal conversion clock is selected. The falling edge of CSTART begins the sampling of the selected analog input. The sampling continues while CSTART is low. The rising edge of CSTART ends the sampling, and starts the conversion (with about 15 ns internal delay). The occurrence of CSTART is independent of SCLK clock, CS, and FS. However, the first CSTART cannot occur before the rising edge of the 11th SCLK. In other words, the falling edge of first CSTART can happen at or after the rising edge of 11th SCLK , but not before. The device enters the extended sampling mode at the falling edge of CSTART and exits this mode once CSTART goes to high followed by two consecutive falling edges of CS or two consecutive rising edges of FS (such as one read data operations followed by WRITE CFR). The first CS or FS does not cause conversion. Extended mode is used when a fast SCLK is not suitable for sampling, or when extended sampling period is needed to accommodate different input signal source impedance. conversion period The conversion period is the third portion of the operation cycle. It begins after the falling edge of 16th SCLK for the normal short sampling mode, or after the falling edge of 48th SCLK for the normal long sampling, or on the rising edge of CSTART (with 15 ns internal delay) for the extended sampling mode. The conversion takes 18 conversion clocks plus 15 ns for TLC3574/78, 13 conversion clocks plus 15 ns for the TLC2574/78. The conversion clock source can be an internal oscillator, OSC, or an external clock, SCLK. The conversion clock is equal to the internal OSC if the internal clock is used, or equal to four SCLKs when the external clock is programmed. To avoid the premature termination of conversion, enough time for the conversion must be allowed between consecutive triggers. EOC goes to low at the beginning of the conversion period and goes to high at the end of the conversion period. INT goes to low at the end of this period, too. conversion mode Four different conversion modes (mode 00, 01, 10, 11) are available. The operation of each mode is slightly different, depending on how the converter samples and what host interface is used. Do not mix different types of triggers throughout the repeat or sweep operations. ONE SHOT Mode (Mode 00): Each operation cycle performs one sampling and one conversion for the selected channel. FIFO is not used. When EOC is selected, it is generated while the conversion period is in progress. Otherwise, INT is generated after the conversion is done. The result is output through the SDO pin during the next select/conversion operation. REPEAT Mode (Mode 01): Each operation cycle performs multiple samplings and conversions for a fixed channel selected according to the 4-bit command. The results are stored in the FIFO. The number of samples to be taken equals the FIFO threshold programmed via D[1:0] in CFR register. Once the threshold is reached, INT is generated, and the operation ends. If the FIFO is not read after the conversions, the data is replaced in the next operation. The operation of this mode starts with the WRITE CFR commands to set conversion mode 01, then the SELECT/CONVERSION commands, followed by a number of samplings and conversions of the fixed channel (triggered by CS, FS, or CSTART) until the FIFO threshold is hit. If CS or FS triggers the sampling, the data on SDI must be any one of the SELECT CHANNEL commands. However, this data is a dummy code for setting the converter in conversion state. It does not change the existing channel selection set at the start of the operation until the FIFO is full. After the operation finishes, the host can read the FIFO, then reselect the channel and start the next REPEAT operation again; or immediately reselect the channel and start next REPEAT operation (by issuing CS or FS or CSTART); or reconfigure the converter then start new operation according to the new setting. If CSTART triggers the sampling, host can also immediately start the next REPEAT operation (on the current channel) after the FIFO is full. Besides, if FS initiates the operation and CSTART triggers the samplings and conversions, CS must not toggle during the conversion. This mode allows the host to set up the converter, continue monitoring a fixed input, and to get a set of samples as needed. WWW.TI.COM 23 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 conversion mode (continued) SWEEP Mode (Mode 10): During each operation, all of the channels listed in the SWEEP SEQUENCE (D[4:3] of CFR register) are sampled and converted one time according to the programmed sequence. The results are stored in the FIFO. When the FIFO threshold is reached, an interrupt (INT) is generated, and the operation ends. If the FIFO threshold is reached before all of the listed channels are visited, the remaining channels are ignored. This allows the host to change the sweep sequence length. The mode 10 operation starts with the WRITE CFR command to set the sweep sequence. The following triggers (CS, FS, or CSTART, depending on the interface) start the samplings and conversions of the listed channels in sequence until the FIFO threshold is hit. If CS or FS starts the sampling, the SDI data must be any one of the SELECT commands to set the converter in conversion state. However, this command is a dummy code. It does not change the existing conversion sequence. After the FIFO is full, the converter waits for FIFO READ. It does nothing before the FIFO READ or WRITE CFR command is issued. The host must read the FIFO completely or WRITE CFR. If CSTART triggers the samplings, the host must issue an extra SELECT/CONVERSION command (select any channel) via CS or FS after the FIFO READ or WRITE CFR. This extra period is named the arm period and is used to set the converter into conversion state, but does not affect the existing conversion sequence. If FS initiates the operation and CSTART triggers the samplings and conversions, CS must not toggle during the conversion. REPEAT SWEEP Mode (Mode 11): This mode works in the same way as mode 10, except that it is not necessary to read the FIFO before the next operation after the FIFO threshold is hit. The next sweep can repeat immediately, but the contents in the FIFO are replaced by the new results. The host can read the FIFO completely, then issue next SWEEP; or repeat the SWEEP immediately (with the existing sweep sequence) by issuing sampling/conversion triggers (CS, FS or CSTART); or change the device setting with the WRITE CFR command. The memory effect of charge redistribution DAC exists when the mux switches from one channel to another. This degrades the channel-to-channel isolation if the channel changes after each conversion. For example, in mode 10 and 11, the isolation is about 70 dB for the sweep sequence 0-1-2-3-4. The memory effect can be reduced by increasing the sampling time or using sweep sequence 0-0-2-2-4-4-6-6 and ignoring the first sample of each channel. 24 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 operation cycle timing CS Initiates Operation 12 SCLKs for Short 44 SCLKs for Long 4 SCLKs t(setup)† SDI § SDO 18 OSC for Internal OSC‡ 72 SCLK for External Clock 15 ns t(convert) t(overhead) t(sample) 4-bit Command 12-bit CFR Data (Optional) 14-bit Data (Previous Conversion) 2-bit Don’t Care Active CS (FS Is Tied to High) CSTAR (For Extended Sampling) occurs at or after the rising edge of eleventh SCLK FS Initiates Operation Delay From CS Low to FS High 4 SCLKs t(delay)† t(setup)† SDI SDO § 12 SCLKs for Short 44 SCLKs for Long 18 OSC for Internal OSC‡ 72 SCLK for External Clock 15 nS t(convert) t(overhead) t(sample) 4-bit Command 12-bit CFR Data (Optional) 14-bit Data (Previous Conversion) 2-bit Don’t Care Active CS (CS Can Be Tied to Low) Active FS CSTAR (For Extended Sampling) occurs at or after the rising edge of eleventh SCLK † Non JEDEC terms used. ‡ 18 internal OSC or 72 SCLK for TLC3574 and TLC3578, 13 internal OSC or 52 SCLK for TLC2574 and TLC2578. § For TLC3574 and TLC3578, 14-bits are result of previous conversion, last two bits are don’t care. For TLC2574 and TLC2578, 12-bits are result of previous conversion, last four bits are don’t care. WWW.TI.COM 25 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 operation cycle timing (continued) After the operation finished, the host has several choices. Table 3 summarizes of operation options. Table 3. Operation Options CONVERSION IS INITIATED BY MODE CS FS CSTART 00 1. Issue new Select/Read operation to read data and start new conversion. 2. Reconfigure the device. 1. Issue new Select/Read operation to read data and start new conversion. 2. Reconfigure the device. 1. Issue new CSTART to start next conversion; old data lost. 2. Issue new Select/Read operation to read data—Issue new CSTART to start new conversion. 3. Reconfigure the device. 01 1. Read FIFO—Select Channel—Start new conversion. Channel must be selected after FIFO READ. 2. Select Channel—Start new conversion (old data lost) 3. Configure device again. 1. Read FIFO—Select Channel—Start new conversion. Channel must be selected after FIFO READ. 2. Select Channel—Start new conversion (old data lost) 3. Configure device again. 1. Read FIFO—Select channel—Start new conversion. Channel must be selected after FIFO READ. 2. Start new conversion (old data lost) with existing setting. 3. Configure device again. 10 1. Read FIFO—Start new conversion with existing setting. 2. Configure device—New conversion (old data lost) 1. Read FIFO—Start new conversion with existing setting. 2. Configure device—New conversion (old data lost) 1. Read FIFO—Arm Period—Start new conversion with existing setting 2. Configure device—Arm Period—New conversion (old data lost) 11 1. Read FIFO—Start new conversion with existing setting. 2. Start new conversion with the existing setting. 3. Configure device—Start new conversion with new setting. 1. Read FIFO—Start new conversion with existing setting 2. Start new conversion with the existing setting. 3. Configure Device—Start new conversion with new setting. 1. Read FIFO—Arm Period—Start new Conversion with existing setting 2. Start new conversion with existing setting. (old data lost) 3. Configure device—Arm Period—New conversion with new setting. operation timing diagrams The nonconversion operation includes FIFO READ and WRITE CFR. Both do not perform a conversion. The conversion operation performs one of four types of conversion: mode 00, 01, 10 and 11 write cycle (WRITE CFR Command): Write cycle does not generate EOC or INT, nor does it carry out any conversion. 1 2 3 4 1D14 ID13 1D12 5 6 ID11 ID10 7 12 13 14 15 1 16 CS FS SDI OR INT EOC SDO ÌÌÌ ÌÌÌ ID15 ID9 ID4 ID3 ID2 ID1 ÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌ ID0 ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌ Hi-Z The dotted lines means signal may or may not exist. Don’t care Figure 8. Write Cycle, FS Initiates Operation 26 WWW.TI.COM ID15 ÌÌÌÌ ÌÌ ÌÌ ÌÌÌÌ 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 operation timing diagrams (continued) 1 2 3 4 5 6 7 12 13 14 15 16 1 CS ÌÌÌÌ ÌÌÌÌ ÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌ FS = High SDI ID15 1D14 ID13 1D12 ID11 ID10 ID9 ID4 ID3 ID2 ID1 ID0 INT OR ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ EOC SDO ÌÌÌ ÌÌÌ ID15 ID14 ÌÌÌÌÌ Hi-Z The dotted lines means signal may or may not exist. Don’t Care Figure 9. Write Cycle, CS Initiates Operation, FS = 1 FIFO READ Operation: When the FIFO is used, the first command after INT is generated is assumed to be the FIFO READ. The first FIFO content is output immediately before the command is decoded. If this command is not FIFO READ, the output is terminated. Using more layers of FIFO reduces the time taken to read multiple conversion results, because the read cycle does not generate an EOC or INT, nor does it make a data conversion. Once the FIFO is read, the entire contents in FIFO must be read out. Otherwise, the remaining data is lost. 1 2 3 4 ID15 1D14 ID13 1D12 5 6 7 12 13 14 15 16 1 SCLK CS ÌÌÌ ÌÌÌ FS = High SDI INT ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ID15 OR EOC SDO ÌÌ ÌÌ OD15 OD14 OD13 OD12 OD11 OD10 OD9 OD4 OD3 The dotted lines means signal may or may not exist. OD2 ÌÌÌÌ ÌÌÌÌ ID14 Hi-Z OD15 OD14 OD[15:2] (for TLC3574/78) or OD[15:4](for TLC2574/78) is the FIFO content. Don’t Care Figure 10. FIFO Read Cycle, CS Initiates Operation, FS = 1 WWW.TI.COM 27 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 conversion operation 48 SCLKs for Long Sampling 16 SCLKs for Short Sampling 1 CS 2 ÌÌÌ ÌÌ ÌÌÌ ÌÌ FS in High SDI INT 3 4 Select Channel ID15 ID14 ID13 5 6 13 12 7 14 15 1 16 ÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌ ÌÌÌÌÌÌÌÌ 1D12 ID15 t(SAMPLE) EOC t(conv) Previous Conversion Result OR SDO OD15 ÌÌ ÌÌ OD14 OD13 OD12 OD11 OD10 OD9 OD4 OD3 The dotted line means signal may or may not exist. ÌÌÌÌÌ OD2 Hi−Z OD15 SDO goes to Hi−Z after 16th SCLK OD[15:2] (for TLC3574/78) or OD [15:4] (for TLC2574/78) is the result of previous conversion. Don’t Care Figure 11. Mode 00, CS Initiates Operation 48 SCLKs for Long Sampling 16 SCLKs for Short Sampling 1 2 3 4 5 6 7 12 13 14 15 1 16 SCLK CS FS SDI INT ÌÌÌ ÌÌÌ Select Channel ID15 1D14 ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ID13 1D12 ID15 t(SAMPLE) OR t(conv) EOC Previous Conversion Result SDO OD15 ÌÌÌ ÌÌÌ ÌÌÌÌ SDO Goes Through Hi-Z After 16 SCLK OD14 OD13 OD12 OD11 OD10 OD9 OD4 OD3 OD2 Hi-Z The dotted line means signal may or may not exist. OD[15:2] (for TLC3574/78) or OD[15:4](for TLC2574/78) is the result of previous conversion. Don’t Care 28 Figure 12. Mode 00, FS Initiates Operation WWW.TI.COM OD15 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 conversion operation (continued) Select Channel 16 SCLK Select Channel 16 SCLK t(sample) CS Tied to Low CSTART Possible Signal FS t(convert) ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ** *** SDI ** INT EOC OR SDO ÌÌ ÌÌ ** Data Lost Previous Conversion Result Hi-Z Conversion Result Hi-Z Hi-Z Possible Signal Select Channel Don’t Care Figure 13. Mode 00, CSTART Triggers Sampling/Conversion, FS Initiates Select CS FS ÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌ ÌÌÌÌÌ ÌÌÌ ÌÌÌÌÌ ÌÌÌ Ì Ì Select CH1 SDI *** ** Select Any Channel ** Select CH2 * * Select Any Channel ** ** DATA1 of CH1 DATA2 of CH1 * * DATA1 of CH2 DATA2 of CH2 Hi-Z SDO 1/4 FIFO FULL 1/4 FIFO FULL INT *** ** * Don’t Care Possible Signal −− WRITE CFR −− Select Channel −− FIFO Read MODE 01, FS Activates Conversion, FIFO Threshold = 1/4 Full Read FIFO After Threshold Is Hit Figure 14. Mode 01, FS Initiates Operations CS FS CSTART ÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌ ÌÌ ÌÌ Select CH1 SDI *** Select CH2 ** * Hi-Z SDO * ** * DATA1 of CH1 DATA2 of CH1 * DATA1 of CH2 DATA2 of CH2 1/4 FIFO FULL 1/4 FIFO FULL INT *** ** * Don’t Care Possible Signal −− WRITE CFR −− Select Channel −− FIFO Read MODE 01, FS Initiates Select Period, CSTART Activates Conversion, FIFO Threshold = 1/4 Full, Read FIFO After Threshold Is Hit Figure 15. Mode 01, CSTART Triggers Samplings/Conversions WWW.TI.COM 29 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 conversion operation (continued) Configure Conversion From CH0 Conversion From CH3 Conversion From CH0 Conversion From CH3 CS ÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌ ÌÌ ÌÌ FS SDI ** *** ** ** ** * * * ** * ** ** ** * INT Hi-Z SDO CH0 1st Sweep CH1 ** * CH0 CH3 2nd Sweep Using Existing Configuration Don’t Care *** CH2 1st FIFO Read Command = Configure Write for Mode 10, FIFO Threshold = 1/2 Full, Sweep Sequence: 0−1−2−3 COMMAND = Select Any Channel COMMAND = Read FIFO 2nd FIFO Read Read FIFO After FIFO Threshold Is Hit Figure 16. Mode 10, FS Initiates Operations CS Tied to Low FS Configure Conversion From CH0 Conversion From CH2 Conversion From CH0 Conversion From CH2 Ì ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌ ÌÌÌÌÌÌÌÌÌ ÌÌÌÌ Ì ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌ ÌÌÌÌÌÌÌÌÌ ÌÌÌÌ ÌÌÌ ÌÌ ÌÌÌ ÌÌ ÌÌ ÌÌ CSTART SDI *** ** * * * * ** * INT Hi-Z SDO CH0 CH0 ** * CH2 CH0 2nd Sweep Using Existing Configuration Don’t Care *** CH2 1st Sweep 2nd FIFO Read 1st FIFO Read Read FIFO After FIFO Threshold Is Hit, FS Initiates Select Period Command = Configure Write for Mode 10, FIFO Threshold = 1/2 Full, Sweep Sequence: 0−0−2−2 COMMAND = Select Any Channel COMMAND = Read FIFO Figure 17. Mode 10, CSTART Initiates Operations Configure Conversion From CH0 Conversion From CH3 Conversion From CH0 Conversion From CH3 Conversion From CH0 CS START 2nd Round SWEEP CONVERSION, the DATA of the 1st Round Are Lost FS=High ÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌ Ì ÌÌ Ì ÌÌ SDI *** ** ** ** ** ** ** INT SDO ** ** ÌÌÌÌÌÌÌÌÌÌÌÌ * CH0 Don’t Care *** ** * CH1 * * CH2 CH3 ** READ the DATA of 2nd Sweep From FIFO Command = Configure Write for Mode 11, FIFO Threshold = 1/2 Full, Sweep Sequence: 0−1−2−3 START 2nd Sweep conversion immediately (NO FIFO READ) after the 1st SWEEP completed. COMMAND = Select Any Channel COMMAND = Read FIFO Figure 18. Mode 11, CS Initiates Operations 30 * WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 conversion operation (continued) Configure Conversion From CH0 Conversion From CH2 Conversion From CH0 Conversion From CH2 CS FS CSTART ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌ Ì Ì Ì *** ** SDI INT 1st SWEEP SDO * * * * CH0 CH0 CH2 CH2 ** * REPEAT CH0 1st FIFO Read Don’t Care *** ** * 2nd FIFO Read READ FIFO after 1st SWEEP Completed Command = Configure Write for Mode 11, FIFO Threshold = 1/2 Full, Sweep Sequence: 0−0−2−2 COMMAND = Select Any Channel COMMAND = Read FIFO Possible Signal Figure 19. Mode 11, CSTART Triggers Samplings/Conversions, FS Initiates SELECT Operation conversion clock and conversion speed The conversion clock source can be the internal OSC, or the external clock, SCLK. The conversion clock is equal to the internal OSC if the internal clock is used, or equal to SCLK/4 when the external clock is selected. It takes 18 conversion clocks plus 15 ns to finish the conversion for TLC3574 and TLC3578, and 13 conversion clocks plus 15 ns for the TLC2574 and TLC2578. If the external clock is selected, the conversion time (not including sampling time) is 18X(4/fSCLK)+15 ns for TLC3574 and TLC3578 and 13X(4/fSCLK)+15 ns for TLC2574 and TLC2578. Table 4 shows the maximum conversion rate (including sampling time) when the analog input source resistor is 25 Ω. Table 4. Maximum Conversion Rate DEVICE TLC3574/78 (Rs = 25 Ω)) TLC2574/78 (Rs = 25 Ω)) SAMPLING MODE CONVERSION CLK MAX SCLK (MHz) CONVERSION TIME (µs) RATE (KSPS) SHORT (16 SCLK) External SCLK/4 10 8.815 113.4 LONG (48 SCLK) External SCLK/4 25 4.815 207.7 SHORT (16 SCLK) Internal 6.5 MHz 10 4.384 228.0 LONG (48 SCLK) Internal 6.5 MHz 25 4.705 212.5 SHORT (16 SCLK) Exernal SCLK/4 10 6.815 146.7 LONG (48 SCLK) External SCLK/4 25 4.015 249.1 SHORT (16 SCLK) Internal 6.5 MHz 10 3.615 276.6 LONG (48 SCLK) Internal 6.5 MHz 25 3.935 254.1 WWW.TI.COM 31 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 FIFO operation Serial SOD ×8 FIFO ADC 7 6 FIFO Full 5 4 3 2 1 0 FIFO 1/2 Full FIFO 3/4 Full FIFO 1/4 Full FIFO Threshold Pointer Figure 20. FIFO Structure FIFO operation (continued) The device has an 8-level FIFO that can be programmed for different thresholds. An interrupt is sent to the host after the preprogrammed threshold is reached. The FIFO is used to store conversion results in mode 01, 10, and 11, from either a fixed channel or a series of channels according to the preprogrammed sweep sequence. For example, an application may require eight measurements from channel 3. In this case, if the threshold is set to full, the FIFO is filled with 8 data conversions sequentially taken from channel 3. Another application may require data from channel 0, 2, 4, and 6 in that order. The threshold is set to 1/2 full and sweep sequence is selected as 0−2−4−6−0−2−4−6. An interrupt is sent to the host as soon as all four data conversions are in the FIFO. FIFO is reset after power on and WRITE CFR operation. The contents of the FIFO are retained during autopower down. Autopower-Down Mode: The device enters the autopower-down state at the end of conversion. The power current is about 20 µA if SCLK stops, and 120 µA maximum if SCLK is running. Active CS , FS, or CSTART resumes the device from power-down state. The bipolar input current is not turned off when device is in power-down mode. The configuration register is not affected by the power-down mode but the SWEEP operation sequence must be started over again. All FIFO contents are retained in power-down mode. 32 WWW.TI.COM 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TYPICAL CHARACTERISTICS INL − Integral Nonlinearity − LSB INTEGRAL NONLINEARITY vs DIGITAL OUTPUT CODE 2 Reference = 4 V AVDD = 5 V, TA = 25°C 1.5 1 0.5 0 −0.5 0 2000 4000 6000 8000 10000 12000 14000 16000 Digital Output Code DNL − Differential Nonlinearity − LSB Figure 21 DIFFERENTIAL NONLINEARITY vs DIGITAL OUTPUT CODE 0.6 0.4 0.2 −0.0 −0.2 −0.4 Reference = 4 V AVDD = 5 V, TA = 25°C −0.6 0 2000 4000 6000 8000 10000 12000 14000 16000 Digital Output Code Figure 22 WWW.TI.COM 33 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TYPICAL CHARACTERISTICS BIPOLAR ZERO ERROR, POSITIVE FULL SCALE ERROR AND NEGATIVE FULL SCALE ERROR (% FS) vs FREE-AIR TEMPERATURE INL (LSB) AND DNL (LSB) vs FREE-AIR TEMPERATURE 0.500 1.3 Reference = 4 V AVDD = 5 V E0 , E FS(+) and E FS(−) (%FS) INL (LSB) and DNL (LSB) Reference = 4 V AVDD = 5 V INL 1 0.7 0.400 Negative Full Scale Error 0.300 Positive Full Scale Error 0.200 DNL 0.4 −40.00 25 TA − Free-Air Temperature − °C Bipolar Zero Error 0.100 −40.00 85 85 25 TA − Free-Air Temperature − °C Figure 23 Figure 24 FFT OF SNR (dB) 00 Reference = 4 V AVDD = 5 V TA = 25°C 200 KSPS Input Signal = 20 kHz, 0dB FFT of SNR − dB −20 −20 −40 −40 −60 −60 −80 −80 −100 −100 −120 −120 −140 −140 −160 −160 −180 −180 0.0 0 24.4 24.4 48.8 48.8 f − Frequency − kHz Figure 25 34 WWW.TI.COM 73.2 73.2 97.6 97.7 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TYPICAL CHARACTERISTICS SINAD vs INPUT SIGNAL FREQUENCY ENOB vs INPUT SIGNAL FREQUENCY 82 80 13.2 Reference = 4 V AVDD = 5 V TA = 25°C Reference = 4 V AVDD = 5 V TA = 25°C ENOB − (Bits) SINAD − dB 12.8 78 76 12 74 72 1k 12.4 60 k 80 k 20 k 40 k fI − Input Signal Frequency − Hz 11.6 1k 100 k Figure 26 100 k Figure 27 TOTAL HARMONIC DISTORTION vs INPUT SIGNAL FREQUENCY SFDR vs INPUT SIGNAL FREQUENCY −78 85 Reference = 4 V AVDD = 5 V TA = 25°C Reference = 4 V AVDD = 5 V TA = 25°C 83 −80 SFDR − dB THD − Total Harmonic Distortion − dB 80 k 20 k 40 k 60 k fI − Input Signal Frequency − Hz 81 −82 79 −84 1k 80 k 20 k 40 k 60 k fI − Input Signal Frequency − Hz 100 k Figure 28 77 1k 80 k 20 k 40 k 60 k fI − Input Signal Frequency − Hz 100 k Figure 29 WWW.TI.COM 35 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 TYPICAL CHARACTERISTICS SUPPLY CURRENT vs FREE-AIR TEMPERATURE SUPPLY CURRENT AT AUTOPOWER DOWN vs FREE-AIR TEMPERATURE 5.6 4 Reference = 4 V AVDD = 5 V SCLK Stops ICC − Supply Current − µ A I CC − Supply Current − mA Reference = 4 V AVDD = 5 V 5.4 5.2 5 −40.00 25 85 TA − Free-Air Temperature − °C Figure 30 36 3 Autopower Down 2 −40 25 TA − Free-Air Temperature − °C Figure 31 WWW.TI.COM 85 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 APPLICATION INFORMATION interface with host Figure 32 shows the examples of the interface between a single converter and host DSP (TMS320C54x DSP) or microprocessor. The C54x is set as FWID=1 (active pulse width=1CLK); (R/X) DATDLY=1 (1 bit data delay); CLK(X/R)P=0 (transmit data are clocked out at rising edge of CLK, receive data are sampled on falling edge of CLK); and FS(X/R)P=1 (FS is active high). If multiple converters connect to the same C54x, use CS as chip select. The host microprocessor is set as the SPI master, CPOL=0 (active high clock), and CPHA=1 (transmit data is clock out at rising edge of CLK, receive data are sampled at falling edge of CLK). 16 bits (or more) per transfer is required. VDD VDD 10 kΩ 10 kΩ TMS320C54X FSR CS FSX FS DX SDI 10 kΩ Host Microprocessor Converter SS DR Converter CS FS Ain MOSI SDI MISO SDO SCK SCLK Ain SDO CLKR SCLK CLKX INT/EOC IRQ IRQ Single Converter Connects to DSP INT/EOC Converter Connects to Microprocessor Figure 32. Typical Interface to Host DSP and Microprocessor sampling time analysis Figure 33 shows the equivalent circuit to evaluate the required sampling time. Req is the Thevenin equivalent resistor (Req = 3.5 K). The C(sampling) is sampling capacitor (30 pF maximum). To get 1/4 LSB accuracy, the sampling capacitor, Csampling, has to be charged to VC = VS ± voltage of 1/4 LSB = VS ± (VS/65532) for 14 bit converter (TLC3574 and TLC3578) = VS ± (VS/16384) for 12 bit converter (TLC2574 and TLC2578) During the sampling time t(sampling), C(sampling) is charge to ȱ ȧ Ȳ V C + V S 1–exp ǒ –t (sampling) Req Ǔȳȴȧ C (sampling) Therefore, the required sampling time is t(sampling) = Req × C(sampling) × In (65532) for 14-bit (TLC3574 and TLC3578) t(sampling) = Req × C(sampling) × In (16384) for 12-bit (TLC2574 and TLC2578). TMS320C54x is a trademark of Texas Instruments. WWW.TI.COM 37 

 
 
      
  
        

 
 
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 SLAS262C − OCTOBER 2000 − REVISED MAY 2003 APPLICATION INFORMATION REFP Bipolar Signal Scaling MUX Req 3.94 kΩ Ain 1.5 kΩ Max 9.9 kΩ Converter Ron Vs 6.6 kΩ C(sample) = 30 pF Max C(sample) = 30 pF Req = Thevenin Equivalent Resistance Vs = Thevenin Equivalent Voltage REFM Figure 33. Equivalent Input Circuit Including the Driving Source 38 WWW.TI.COM PACKAGE OPTION ADDENDUM www.ti.com 14-Oct-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) TLC2574IDW ACTIVE SOIC DW 20 25 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC2574I Samples TLC2574IPW ACTIVE TSSOP PW 20 70 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 Y2574 Samples TLC2578IDW ACTIVE SOIC DW 24 25 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC2578I Samples TLC2578IPW ACTIVE TSSOP PW 24 60 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 Y2578 Samples TLC2578IPWR ACTIVE TSSOP PW 24 2000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 Y2578 Samples TLC3574IDW ACTIVE SOIC DW 20 25 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC3574I Samples TLC3574IDWG4 ACTIVE SOIC DW 20 25 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC3574I Samples TLC3574IDWR ACTIVE SOIC DW 20 2000 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC3574I Samples TLC3574IPW ACTIVE TSSOP PW 20 70 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 Y3574 Samples TLC3578IDW ACTIVE SOIC DW 24 25 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC3578I Samples TLC3578IDWG4 ACTIVE SOIC DW 24 25 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC3578I Samples TLC3578IDWR ACTIVE SOIC DW 24 2000 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 85 TLC3578I Samples TLC3578IPW ACTIVE TSSOP PW 24 60 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 Y3578 Samples TLC3578IPWR ACTIVE TSSOP PW 24 2000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 Y3578 Samples (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". Addendum-Page 1 PACKAGE OPTION ADDENDUM www.ti.com 14-Oct-2022 RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of