TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 3.0-V TO 5.5-V, 12-BIT, 200-KSPS, 4-/8-CHANNEL, LOW-POWER SERIAL ANALOG-TO-DIGITAL CONVERTER WITH AUTOPOWER-DOWN Check for Samples: TLV2548-EP FEATURES 1 • • • • • • • • • • • • Maximum Throughput 200-KSPS Built-In Reference, Conversion Clock and 8x FIFO Differential/Integral Nonlinearity Error: ±1.2 LSB Signal-to-Noise and Distortion Ratio: 70 dB, fi = 12 kHz Spurious Free Dynamic Range: 75 dB, fi = 12 kHz SPI (CPOL = 0, CPHA = 0)/DSP-Compatible Serial Interfaces With SCLK up to 20 MHz Single Wide Range Supply 3.0 Vdc to 5.5 Vdc Analog Input Range 0 V to Supply Voltage With 500-kHz BW Hardware Controlled and Programmable Sampling Period Low Operating Current (1.0 mA at 3.3 V, 2.0 mA at 5.5 V With External Ref, 1.7-mA at 3.3V, 2.4-mA at 5.5-V With Internal Ref) Power Down: Software/Hardware Power-Down Mode (1 μA Max, Ext Ref), Autopower-Down Mode (1 μA, Ext Ref) Programmable Auto-Channel Sweep SUPPORTS DEFENSE, AEROSPACE, AND MEDICAL APPLICATIONS • • • • • • • Controlled Baseline One Assembly/Test Site One Fabrication Site Available in Military (–55°C/125°C) Temperature Range (1) Extended Product Life Cycle Extended Product-Change Notification Product Traceability PW PACKAGE (TOP VIEW) SDO SDI SCLK EOC/(INT) VCC A0 A1 A2 A3 A4 (1) 1 20 2 19 3 18 4 17 5 16 6 15 7 14 8 13 9 12 10 11 CS REFP REFM FS PWDN GND CSTART A7 A6 A5 Custom temperature ranges available DESCRIPTION The TLV2548 is a high performance, 12-bit low-power, 3.86-μs, CMOS analog-to-digital converter (ADC) which operates from a single 3.0-V to 5.5-V power supply. This device has three digital inputs and a 3-state output [chip select (CS), serial input-output clock (SCLK), serial data input (SDI), and serial data output (SDO)] that provide a direct 4-wire interface to the serial port of most popular host microprocessors (SPI interface). When interfaced with a TI DSP, a frame sync (FS) signal is used to indicate the start of a serial data frame. In addition to a high-speed A/D converter and versatile control capability, this device has an on-chip analog multiplexer that can select any analog inputs or one of three internal self-test voltages. The sample-and-hold function is automatically started after the fourth SCLK edge (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 (12 SCLKs) or as long (24 SCLKs) to accommodate faster SCLK operation popular among high-performance signal processors. The TLV2548 is designed to operate with very low power consumption. The power-saving feature is further enhanced with software/hardware/autopower-down modes and programmable conversion speeds. The conversion clock (OSC) and reference are built-in. The converter can use the external SCLK as the source of the conversion clock to achieve higher (up to 2.8 μs when a 20-MHz SCLK is used) conversion speed. Two different internal reference voltages are available. An optional external reference can also be used to achieve maximum flexibility. The TLV2548 is characterized for operation from –55°C to 125°C. 1 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. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2009, Texas Instruments Incorporated TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com FUNCTIONAL BLOCK DIAGRAM VCC 4/2 V Reference REFP REFM Analog MUX A0 A1 A2 A3 A4 A5 A6 A7 FIFO 12 Bit × 8 S/H Low Power 12-BIT SAR ADC OSC INT Command Decode EXT Conversion Clock M U X CFR SDI SDO CMR (4 MSBs) DIV SCLK CS FS CSTART PWDN Control Logic EOC/(INT) GND Table 1. ORDERING INFORMATION (1) TA PACKAGE –55°C to 125°C (1) (2) TSSOP-PW (2) Tape and Reel of 2000 ORDERABLE PART NUMBER TOP-SIDE MARKING TLV2548MPWREP TV2548EP For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI Web site at www.ti.com. Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at www.ti.com/sc/package. Table 2. TERMINAL FUNCTIONS TERMINAL NAME NO. A0 A1 A2 A3 A4 A5 A6 A7 6 7 8 9 10 11 12 13 CS 2 I/O 20 DESCRIPTION I Analog signal inputs. The analog inputs are applied to these terminals and are internally multiplexed. The driving source impedance should be less than or equal to 1 kΩ. xxx For a source impedance greater than 1 kΩ, use the asynchronous conversion start signal CSTART (CSTART low time controls the sampling period) or program long sampling period to increase the sampling time. I Chip select. A high-to-low transition on the CS input resets the internal 4-bit counter, enables SDI, and removes SDO from 3-state within a maximum setup time. SDI is disabled within a setup time after the 4-bit counter counts to 16 (clock edges) or a low-to-high transition of CS whichever happens first. NOTE: CS falling and rising edges need to happen when SCLK is low for a microprocessor interface such as SPI. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 Table 2. TERMINAL FUNCTIONS (continued) TERMINAL NAME CSTART EOC/(INT) NO. 14 4 I/O DESCRIPTION I This terminal controls the start of sampling of the analog input from a selected multiplex channel. Sampling time starts with the falling edge of CSTART and ends with the rising edge of CSTART as long as CS is held high. In mode 01, select cycle, CSTART can be issued as soon as CHANNEL is selected which means the fifth SCLK during the select cycle, but the effective sampling time is not started until CS goes to high. The rising edge of CSTART (when CS = 1) also starts the conversion. Tie this terminal to VCC if not used. O End of conversion or interrupt to host processor. [PROGRAMMED AS EOC]: This output goes from a high-to-low logic level at the end of the sampling period and remains low until the conversion is complete and data are ready for transfer. EOC is used in conversion mode 00 only. xxx [PROGRAMMED AS INT]: This pin can also be programmed as an interrupt output signal to the host processor. The falling edge of INT indicates data are ready for output. The following CS↓ or FS clears INT. FS 17 I DSP frame sync input. Indication of the start of a serial data frame in or out of the device. If FS remains low after the falling edge of CS, SDI is not enabled until an active FS is presented. A high-to-low transition on the FS input resets the internal 4-bit counter and enables SDI within a maximum setup time. SDI is disabled within a setup time after the 4-bit counter counts to 16 (clock edges) or a low-to-high transition of CS whichever happens first. xxx Tie this terminal to VCC if not used. See the Data Code Information section, item 1. GND 15 I Ground return for the internal circuitry. Unless otherwise noted, all voltage measurements are with respect to GND. PWDN 16 I Both analog and reference circuits are powered down when this pin is at logic zero. The device can be restarted by active CS, FS or CSTART after this pin is pulled back to logic one. I Input serial clock. This terminal receives the serial SCLK from the host processor. SCLK is used to clock the input SDI to the input register. When programmed, it may also be used as the source of the conversion clock. NOTE: This device supports CPOL (clock polarity) = 0, which is SCLK returns to zero when idling for SPI compatible interface. I Serial data input. The input data is presented with the MSB (D15) first. The first 4-bit MSBs, D(15−12) are decoded as one of the 16 commands. The configure write commands require an additional 12 bits of data. xxx When FS is not used (FS =1), the first MSB (D15) is expected after the falling edge of CS and is latched in on the rising edges of SCLK (after CS↓). xxx When FS is used (typical with an active FS from a DSP) the first MSB (D15) is expected after the falling edge of FS and is latched in on the falling edges of SCLK. xxx SDI is disabled within a setup time after the 4-bit counter counts to 16 (clock edges) or a low-to-high transition of CS whichever happens first. SCLK SDI 3 2 SDO 1 O The 3-state serial output for the A/D conversion result. SDO is kept in the high-impedance state when CS is high and after the CS falling edge and until the MSB is presented. The output format is MSB first. xxx When FS is not used (FS = 1 at the falling edge of CS), the MSB is presented to the SDO pin after the CS falling edge, and successive data are available at the rising edge of SCLK and changed on the falling edge. xxx When FS is used (FS = 0 at the falling edge of CS), the MSB is presented to SDO after the falling edge of CS and FS = 0 is detected. Successive data are available at the falling edge of SCLK and changed on the rising edge. (This is typically used with an active FS from a DSP.) xxx For conversion and FIFO read cycles, the first 12 bits are result from previous conversion (data) followed by 4 don’t care bits. The first four bits from SDO for CFR read cycles should be ignored. The register content is in the last 12 bits. SDO is 3-state (float) after the 16th bit. See the Data Code Information section, item 2. REFM 18 I External reference input or internal reference decoupling. Tie this pin to analog ground if internal reference is used. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 3 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com Table 2. TERMINAL FUNCTIONS (continued) TERMINAL I/O DESCRIPTION NAME NO. REFP 19 I External reference input or internal reference decoupling (shunt capacitors of 10 μF and 0.1 μF between REFP and REFM). The maximum input voltage range is determined by the difference between the voltage applied to this terminal and the REFM terminal when an external reference is used. VCC 5 I Positive supply voltage Detailed Description Analog Inputs and Internal Test Voltages The 4/8 analog inputs and three internal test inputs are selected by the analog multiplexer depending on the command entered. The input multiplexer is a break-before-make type to reduce input-to-input noise injection resulting from channel switching. Converter The TLV2548 uses a 12-bit successive approximation ADC utilizing a charge redistribution DAC. Figure 1 shows a simplified version of the ADC. The sampling capacitor acquires the signal on Ain during the sampling period. When the conversion process starts, the SAR control logic and charge redistribution DAC are used to add and subtract fixed amounts of charge from the sampling capacitor to bring the comparator into a balanced condition. When the comparator is balanced, the conversion is complete and the ADC output code is generated. Charge Redistribution DAC _ Ain Control Logic + ADC Code REFM Figure 1. Simplified Model of the Successive-Approximation System Serial Interface INPUT DATA FORMAT MSB LSB D15−D12 D11−D0 Command ID[15:12] Configuration data field ID[11:0] Input data is binary. All trailing blanks can be filled with zeros. OUTPUT DATA FORMAT READ CFR/FIFO READ MSB 4 LSB D15−D12 D11−D0 Don’t care Register content or FIFO content OD[11:0] Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 OUTPUT DATA FORMAT CONVERSION MSB LSB D15−D4 D3−D0 Conversion result OD[11:0] Don’t care The output data format is binary (unipolar straight binary). Binary Zero scale code = 000h, Vcode = VREFM. Full scale code = FFFh, Vcode = VREFP − 1 LSB Control and Timing Power Up and Initialization Requirements • Determine processor type by writing A000h to the TLV2548 (CS must be toggled). • Configure the device (CS must make a high-to-low transition, then can be held low if in DSP mode; i.e., active FS). The first conversion after power up or resuming from power down is not valid. Start of the Cycle • When FS is not used (FS = 1 at the falling edge of CS), the falling edge of CS is the start of the cycle. • When FS is used (FS is an active signal from a DSP), the falling edge of FS is the start of the cycle. First 4-MSBs: The Command Register (CMR) The TLV2548 has a 4-bit command set (see Table 3) plus a 12-bit configuration data field. Most of the commands require only the first 4 MSBs, i.e., without the 12-bit data field. The valid commands are listed in Table 3. Table 3. TLV2548 Command Set (1) SDI D(15−12) BINARY (1) COMMAND 0000b 0h Select analog input channel 0 0001b 1h Select analog input channel 1 0010b 2h Select analog input channel 2 0011b 3h Select analog input channel 3 0100b 4h Select analog input channel 4 0101b 5h Select analog input channel 5 0110b 6h Select analog input channel 6 0111b 7h Select analog input channel 7 1000b 8h SW power down (analog + reference) 1001b 9h Read CFR register data shown as SDO D(11-0) 1010b Ah plus data Write CFR followed by 12–bit data, e.g., 0A100h means external reference, short sampling, SCLK/4, single shot, INT 1011b Bh Select test, voltage = (REFP+REFM)/2 1100b Ch Select test, voltage = REFM 1101b Dh Select test, voltage = REFP 1110b Eh FIFO read, FIFO contents shown as SDO D(15-4), D(3-0) = 0000 1111b Fh plus data Reserved The status of the CFR can be read with a read CFR command when the device is programmed for one–shot conversion mode (CFR D[6,5] = 00). Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 5 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com Configuration Configuration data is stored in one 12–bit configuration register (CFR) (see Table 4 for CFR bit definitions). Once configured after first power up, the information is retained in the H/W or S/W power down state. When the device is being configured, a write CFR cycle is issued by the host processor. This is a 16–bit write. If the SCLK stops after the first eight bits are entered, then the next eight bits can be taken after the SCLK is resumed. Table 4. TLV2548 Configuration Register (CFR) Bit Definitions BIT D11 D10 Internal reference voltage select 0: Internal ref = 4 V 1: internal ref = 2 V D9 Sample period select 0: Short sampling 12 SCLKs (1x sampling time) 1: Long sampling 24 SCLKs (2x sampling time) D(8,7) Conversion clock source select 00: Conversion clock = internal OSC 01: Conversion clock = SCLK 10: Conversion clock = SCLK/4 11: Conversion clock = SCLK/2 D(6,5) Conversion mode select 00: Single shot mode [FIFO not used, D(1,0) has no effect.] 01: Repeat mode 10: Sweep mode 11: Repeat sweep mode D(4,3) (1) Sweep auto sequence select 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 D2 EOC/INT - pin function select 0: Pin used as INT 1: Pin used as EOC D(1,0) (1) DEFINITION Reference select 0: External 1: Internal (Tie REFM to analog ground if the internal reference is selected.) FIFO trigger level (sweep sequence length) 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) These bits only take effect in conversion modes 10 and 11. Sampling The sampling period starts after the first four input data are shifted in if they are decoded as one of the conversion commands. These are select analog input (channels 0 through 7) and select test (channels 1 through 3). Normal Sampling When the converter is using normal sampling, the sampling period is programmable. It can be 12 SCLKs (short sampling) or 24 SCLKs (long sampling). Long sampling helps when SCLK is faster than 10 MHz or when input source resistance is high. Extended Sampling CSTART - An asynchronous (to the SCLK) signal, via dedicated hardware pin, CSTART, can be used in order to have total control of the sampling period and the start of a conversion. This extended sampling is user defined and is totally independent of SCLK. While CS is high, the falling edge of CSTART is the start of the sampling period and is controlled by the low time of CSTART. The minimum low time for CSTART should be at least equal to the minimum t(SAMPLE). In a select cycle used in mode 01 (REPEAT MODE), CSTART can be started as soon 6 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 as the channel is selected (after the fifth SCLK). In this case the sampling period is not started until CS has become inactive. Therefore the non-overlapped CSTART low time must meet the minimum sampling time requirement. The low–to–high transition of CSTART terminates the sampling period and starts the conversion period. The conversion clock can also be configured to use either internal OSC or external SCLK. This function is useful for an application that requires: • The use of an extended sampling period to accommodate different input source impedance. • The use of a faster I/O clock on the serial port but not enough sampling time is available due to the fixed number of SCLKs. This could be due to a high input source impedance or due to higher MUX ON resistance at lower supply voltage. Once the conversion is complete, the processor can initiate a read cycle by using either the read FIFO command to read the conversion result or by simply selecting the next channel number for conversion. Since the device has a valid conversion result in the output buffer, the conversion result is simply presented at the serial data output. To completely get out of the extended sampling mode, CS must be toggled twice from a high-to-low transition while CSTART is high. The read cycle mentioned above followed by another configuration cycle of the ADC qualifies this condition and successfully puts the ADC back to its normal sampling mode. This can be viewed in Figure 9. Table 5. Sample and Convert Conditions CONDITIONS CSTART CS = 1 (see Figure 11 and Figure 19) CS CSTART = 1 FS = 1 FS CSTART = 1 CS = 0 SAMPLE CONVERT No sampling clock (SCLK) required. Sampling period is totally controlled by the low time of CSTART. The high–to–low transition of CSTART (when CS = 1) starts the sampling of the analog input signal. The low time of CSTART dictates the sampling period. The low–to–high transition of CSTART ends sampling period and begins the conversion cycle. (Note: this trigger only works when internal reference is selected for conversion modes 01, 10, and 11.) 1) If the internal clock OSC is selected, a maximum conversion time of 3.86 μs can be SCLK is required. Sampling period is programmable under normal sampling. When achieved. programmed to sample under short sampling, 2) If external SCLK is selected, conversion time is tconv = 14 x DIV/f(SCLK), where DIV can 12 SCLKs are generated to complete be 1, 2, or 4. sampling period. 24 SCLKs are generated when programmed for long sampling. A command set to configure the device requires 4 SCLKs thereby extending to 16 or 28 SCLKs respectively before conversion takes place. (Note: Because the ADC only bypasses a valid channel select command, the user can use select channel 0, 0000b, as the SDI input when either CS or FS is used as trigger for conversion. The ADC responds to commands such as SW powerdown, 1000b.) TLV2548 Conversion Modes The TLV2548 has four different conversion modes (mode 00, 01, 10, 11). The operation of each mode is slightly different, depending on how the converter performs the sampling and which host interface is used. The trigger for a conversion can be an active CSTART (extended sampling), CS (normal sampling, SPI interface), or FS (normal sampling, TMS320 DSP interface). When FS is used as the trigger, CS can be held active, i.e. CS does not need to be toggled through the trigger sequence. SDI can be one of the channel select commands, such as SELECT CHANNEL 0. Different types of triggers should not be mixed throughout the repeat and sweep operations. When CSTART is used as the trigger, the conversion starts on the rising edge of CSTART. The minimum low time for CSTART is equal to t(SAMPLE). If an active CS or FS is used as the trigger, the conversion is started after the 16th or 28th SCLK edge. Enough time (for conversion) should be allowed between consecutive triggers so that no conversion is terminated prematurely. One Shot Mode (Mode 00) One shot mode (mode 00) does not use the FIFO, and the EOC is generated as the conversion is in progress (or INT is generated after the conversion is done). Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 7 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com Repeat Mode (Mode 01) Repeat mode (mode 01) uses the FIFO. This mode setup requires configuration cycle and channel select cycle. Once the programmed FIFO threshold is reached, the FIFO must be read, or the data is lost when the sequence starts over again with the SELECT cycle and series of triggers. No configuration is required except for re-selecting the channel unless the operation mode is changed. This allows the host to set up the converter and continue monitoring a fixed input and come back to get a set of samples when preferred. Triggered by CSTART: The first conversion can be started with a select cycle or CSTART. To do so, the user can issue CSTART during the select cycle, immediately after the 4-bit channel select command. The first sample started as soon as the select cycle is finished (i.e., CS returns to 1). If there is enough time (2 μs) left between the SELECT cycle and the following CSTART, a conversion is carried out. In this case, you need one less trigger to fill the FIFO. Succeeding samples are triggered by CSTART. Sweep Mode (Mode 10) Sweep mode (mode 10) also uses the FIFO. Once it is programmed in this mode, all of the channels listed in the selected sweep sequence are visited in sequence. The results are converted and stored in the FIFO. This sweep sequence may not be completed if the FIFO threshold is reached before the list is completed. This allows the system designer to change the sweep sequence length. Once the FIFO has reached its programmed threshold, an interrupt (INT) is generated. The host must issue a read FIFO command to read and clear the FIFO before the next sweep can start. Repeat Sweep Mode (Mode 11) Repeat sweep mode (mode 11) works the same way as mode 10 except the operation has an option to continue even if the FIFO threshold is reached. Once the FIFO has reached its programmed threshold, an interrupt (INT) is generated. Then two things may happen: 1. The host may choose to act on it (read the FIFO) or ignore it. If the next cycle is a read FIFO cycle, all of the data stored in the FIFO is retained until it has been read in order. 2. If the next cycle is not a read FIFO cycle, or another CSTART is generated, all of the content stored in the FIFO is cleared before the next conversion result is stored in the FIFO, and the sweep is continued. Table 6. TLV2548 Conversion Mode (1) CONVERSION MODE One shot (1) (2) (3) 8 CFR D(6,5) SAMPLING TYPE (2) (3) OPERATION Normal • • • • Single conversion from a selected channel CS or FS to start select/sampling/conversion/read One INT or EOC generated after each conversion Host must serve INT by selecting channel, and converting and reading the previous output. Extended • • • • • Single conversion from a selected channel CS to select/read CSTART to start sampling and conversion One INT or EOC generated after each conversion Host must serve INT by selecting next channel and reading the previous output. 00 Programming the EOC/INT pin as the EOC signal works for mode 00 only. The other three modes automatically generate an INT signal irrespective of how EOC/INT is programmed. Extended sampling mode using CSTART as the trigger only works when internal reference is selected for conversion modes 01, 10, and 11. When using CSTART to sample in extended mode, the falling edge of the next CSTART trigger should occur no more than 2.5 μs after the falling CS edge (or falling FS edge if FS is active) of the channel select cycle. This is to prevent an ongoing conversion from being canceled. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 Table 6. TLV2548 Conversion Mode CONVERSION MODE CFR D(6,5) SAMPLING TYPE Sweep • • • • Repeated conversions from a selected channel CS or FS to start sampling/conversion One INT generated after FIFO is filled up to the threshold Host must serve INT by either 1) (FIFO read) reading out all of the FIFO contents up to the threshold, then repeat conversions from the same selected channel or 2) writing another command(s) to change the conversion mode. If the FIFO is not read when INT is served, it is cleared. Extended • Same as normal sampling except CSTART starts each sampling and conversion when CS is high. Normal • • • • One conversion per channel from a sequence of channels CS or FS to start sampling/conversion One INT generated after FIFO is filled up to the threshold Host must serve INT by (FIFO read) reading out all of the FIFO contents up to the threshold, then write another command(s) to change the conversion mode. Extended • Same as normal sampling except CSTART starts each sampling and conversion when CS is high. • • • • Repeated conversions from a sequence of channels CS or FS to start sampling/conversion One INT generated after FIFO is filled up to the threshold Host must serve INT by either 1) (FIFO read) reading out all of the FIFO contents up to the threshold, then repeat conversions from the same selected channel or 2) writing another command(s) to change the conversion mode. If the FIFO is not read when INT is served it is cleared. • Same as normal sampling except CSTART starts each sampling and conversion when CS is high. 01 10 Normal Repeat sweep (continued) OPERATION Normal Repeat (1) (2) (3) 11 Extended Timing Diagrams The timing diagrams can be categorized into two major groups: non-conversion and conversion. The non-conversion cycles are read and write (configuration). None of these cycles carry a conversion. Conversion cycles are those four modes of conversion. Read Cycle (Read FIFO or Read CFR) Read CFR Cycle The read command is decoded in the first four clocks. SDO outputs the contents of the CFR after the fourth SCLK. This command works only when the device is programmed in the single shot mode (mode 00). 1 2 3 4 5 6 7 12 13 14 15 1 16 SCLK CS FS SDI ID15 ID14 ID13 ID12 ID15 INT EOC OD11 OD10 OD9 SDO OD4 OD3 OD2 OD1 OD0 Figure 2. TLV2548 Read CFR Cycle (FS active) Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 9 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com 1 2 3 4 5 7 6 13 12 14 15 1 16 SCLK CS FS SDI ID15 ID14 ID13 ID12 ID15 ID14 INT EOC OD11 OD10 SDO OD9 OD4 OD3 OD2 OD1 OD0 Figure 3. TLV2548 Read CFR Cycle (FS = 1) FIFO Read Cycle The first command in the active cycle after INT is generated, if the FIFO is used, is assumed as the FIFO read command. The first FIFO content is output immediately before the command is decoded. If this command is not a FIFO read, then the output is terminated but the first data in the FIFO is retained until a valid FIFO read command is decoded. Use of more layers of the FIFO reduces the time taken to read multiple data. This is because the read cycle does not generate EOC or INT, nor does it carry out any conversion. 1 2 3 4 5 6 7 12 13 14 15 16 1 2 ID15 ID14 SCLK CS FS SDI ID15 ID14 ID13 ID12 INT EOC SDO OD11 OD10 OD9 OD8 OD7 OD6 OD5 OD0 OD11 OD10 These devices can perform continuous FIFO read cycles (FS = 1) controlled by SCLK; SCLK can stop between each 16 SCLKs. Figure 4. TLV2548 FIFO Read Cycle (FS = 1) 10 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 Write Cycle (Write CFR) The write cycle is used to write to the configuration register CFR (with 12-bit register content). The write cycle does not generate an EOC or INT, nor does it carry out any conversion (see power up and initialization requirements). 1 2 3 4 5 6 7 ID11 ID10 ID9 12 13 14 15 16 1 SCLK CS FS SDI ID15 ID14 ID13 ID12 ID4 ID3 ID2 ID1 ID0 ID15 INT EOC SDO Figure 5. TLV2548 Write Cycle (FS Active) 1 2 3 4 5 6 7 12 13 14 15 16 ID12 ID11 ID10 ID9 ID4 ID3 ID2 ID1 ID0 1 SCLK CS FS SDI ID15 ID14 ID13 ID15 ID14 INT EOC SDO Figure 6. TLV2548 Write Cycle (FS = 1) Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 11 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com Conversion Cycles DSP/Normal Sampling 1 2 3 4 5 6 7 12 16 Short Sampling 30 Short Sampling 28 Long Sampling 42 Long Sampling (If CONV CLK = SCLK0 SCLK tc (30 or 42 SCLKs) CS FS SDI ID15 ID14I ID13 ID12 ID15 INT t(sample) (12 or 24 SCLKs) EOC SDO (SDOZ on SCLK16L Regardless of Sampling Time) MSB-1 MSB MSB-2 MSB-3 MSB-4 MSB-5 MSB-6 t(conv) LSB MSB Figure 7. Mode 00 Single Shot/Normal Sampling (FS Signal Used) 16 Short Sampling 1 2 3 4 5 6 7 12 13 28 Long Sampling 30 Short Sampling 42 Long Sampling (If CONV CLK = SCLK0 1 SCLK tc (30 or 42 SCLKs) CS FS SDI ID15 ID14 ID13 ID12 ID15 INT t(sample) (12 or 24 SCLKs) EOC SDO (SDOZ on SCLK16L Regardless of Sampling Time) MSB MSB-1 MSB-2 MSB-3 MSB-4 MSB-5 MSB-6 t(conv) LSB MSB Figure 8. Mode 00 Single Shot/Normal Sampling (FS = 1, FS Signal Not Used) 12 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 Device Going Into Extended Sampling Mode Select/Read Cycle Select/Read Cycle Read Cycle Device Get Out Extended Sampling Mode CS t(sample ) Normal Cycle CSTART FS t(conv) † † SDI INT EOC SDO Previous Conversion Result Previous Conversion Result Hi-Z Hi-Z Hi-Z † This is one of the single shot commands. Conversion starts on next rising edge of CSTART. Figure 9. Mode 00 Single Shot/Extended Sampling (FS Signal Used, FS Pin Connected to TMS320 DSP) Modes Using the FIFO: Modes 01, 10, 11 Timing Configure Select Conversion #1 From Channel 2 Conversion #4 From Channel 2 Select CS FS CSTART SDI † § ¶ ¶ ¶ ‡ ‡ ‡ ‡ § ¶ INT Hi-Z Hi-Z SDO Read FIFO #1 Top of FIFO #2 #3 #4 † Command = Configure write for mode 01, FIFO threshold = 1/2 ‡ Command = Read FIFO, first FIFO read § Command = Select ch2. ¶ Use any channel select command to trigger SDI input. Figure 10. TLV2548 Mode 01 DSP Serial Interface (Conversions Triggered by FS) Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 13 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com Conversion #1 From Channel 2 Configure Select CS Conversion #4 From Channel 2 Select ¶ FS (DSP) t(sample) t(sample) t(sample) t(sample) CSTART SDI † § ‡ ‡ ‡ ‡ § INT Hi-Z SDO Hi-Z Read FIFO #1 #2 First FIFO Read Sample Times ≥ MIN t(sample) (See Operating Characteristics) #3 #4 † Command = Configure write for mode 01, FIFO threshold = 1/2 ‡ Command = Read FIFO, first FIFO read § Command = Select ch2. ¶ Minimum CS low time for select cycle is 6 SCLKs. The same amount of time is required between FS low to CSTART for proper channel decoding. The low time of CSTART, not overlapped with CS low time, is the valid sampling time for the select cycle (see Figure 19). Figure 11. TLV2548 Mode 01 μp/DSP Serial Interface (Conversions Triggered by CSTART) Conversion From Channel 0 Configure Conversion From Channel 3 Conversion From Channel 0 Conversion From Channel 3 CS FS (DSP) CSTART SDI † § § § § ‡ ‡ ‡ ‡ § § § § ‡ Read FIFO #1 INT SDO Repeat Read FIFO #1 #2 #3 Top of FIFO First FIFO Read #4 Repeat Second FIFO Read † Command = Configure write for mode 10 or 11, FIFO threshold = 1/2, sweep seq = 0-1-2-3. ‡ Command = Read FIFO § Use any channel select command to trigger SDI input. Figure 12. TLV2548 Mode 10/11 DSP Serial Interface (Conversions Triggered by FS) 14 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 Conversion From Channel 0 Conversion From Channel 3 Conversion From Channel 3 Conversion From Channel 0 Configure CS FS (DSP) CSTART t(sample) t(sample) t(sample) t(sample) SDI ‡ † ‡ ‡ ‡ #3 #4 ‡ INT SDO Read FIFO Repeat #1 #2 Top of FIFO Read FIFO Repeat #1 Second FIFO Read First FIFO Read † Command = Configure write for mode 10 or 11, FIFO threshold = 1/2, sweep seq = 0-1-2-3. ‡ Command = Read FIFO Figure 13. TLV2548 Mode 10/11 DSP Serial Interface (Conversions Triggered by CSTART) Conversion From Channel 0 Conversion From Channel 0 Conversion From Channel 3 Conversion From Channel 3 Configure CS CSTART SDI † § § § § ‡ ‡ ‡ ‡ § § § § ‡ INT SDO Read FIFO Repeat #1 #2 #3 Top of FIFO First FIFO Read #4 Read FIFO #1 Repeat Second FIFO Read † Command = Configure write for mode 10 or 11, FIFO threshold = 1/2, sweep seq = 0-1-2-3. ‡ Command = Read FIFO § Use any channel select command to trigger SDI input. Figure 14. TLV2548 Mode 10/11 μp Serial Interface (Conversions Triggered by CS) Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 15 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com FIFO Operation Serial SDO 12-BITx8 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 15. TLV2548 FIFO The device has an eight-layer FIFO that can be programmed for different thresholds. An interrupt is sent to the host after the pre-programmed threshold is reached. The FIFO can be used to store data from either a fixed channel or a series of channels based on a pre-programmed sweep sequence. For example, an application may require eight measurements from channel 3. In this case, the FIFO is filled with eight data sequentially taken from channel 3. Another application may require data from channel 0, channel 2, channel 4, and channel 6 in an orderly manner. Therefore, the threshold is set for 1/2 and the sweep sequence 0−2−4−6−0−2−4−6 is chosen. An interrupt is sent to the host as soon as all four data are in the FIFO. In single shot mode, the FIFO automatically uses a 1/8 FIFO depth. Therefore the CFR bits (D1,0) controlling FIFO depth are don’t care. SCLK and Conversion Speed There are two ways to adjust the conversion speed. • The SCLK can be used as the source of the conversion clock to get the highest throughput of the device. The minimum onboard OSC is 3.6 MHz and 14 conversion clocks are required to complete a conversion (corresponding 3.86-μs conversion time). The devices can operate with an SCLK up to 20 MHz for the supply voltage range specified. When a more accurate conversion time is desired, the SCLK can be used as the source of the conversion clock. The clock divider provides speed options appropriate for an application where a high speed SCLK is used for faster I/O. The total conversion time is 14 x (DIV/fSCLK) where DIV is 1, 2, or 4. For example a 20-MHz SCLK with the divide by 4 option produces a 14 x (4/20 M) = 2.8-μs conversion time. When an external serial clock (SCLK) is used as the source of the conversion clock, the maximum equivalent conversion clock (fSCLK/DIV) should not exceed 6 MHz. • Autopower down can be used to slow down the device at a reduced power consumption level. This mode is always used by the converter. If the device is not accessed (by CS or CSTART), the converter is powered down to save power. The built-in reference is left on in order to quickly resume operation within one half SCLK period. This provides unlimited choices to trade speed with power savings. Reference Voltage The device has a built-in reference with a programmable level of 2 V or 4 V. If the internal reference is used, REFP is set to 2 V or 4 V and REFM should be connected to the analog ground of the converter. An external reference can also be used through two reference input pins, REFP and REFM, if the reference source is programmed as external. The voltage levels applied to these pins establish the upper and lower limits of the analog inputs to produce a full-scale and zero-scale reading respectively. The values of REFP, REFM, and the analog input should not exceed the positive supply or be lower than GND consistent with the specified absolute maximum ratings. The digital output is at full scale when the input signal is equal to or higher than REFP and at zero when the input signal is equal to or lower than REFM. 16 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 Reference Block Equivalent Circuit INTERNAL REF Close = Int Ref Used Open = Ext Ref Used REFP Sample 0.1- mF Decoupling Cap Convert 10-mF Internal Reference Compensation Cap ~50 pF CDAC REFM (See Note 1) External to the Device A. If internal reference is used, tie REFM to analog ground and install a 10-μF (or 4.7-μF) internal reference compensation capacitor between REFP and REFM to store the charge as shown in the figure above. B. If external reference is used, the 10-μF (internal reference compensation) capacitor is optional. REFM can be connected to external REFM or AGND. C. Internal reference voltage drift, due to temperature variations, is approximately ±10 mV about the nominal 2 V (typically) from –10°C to 100°C. The nominal value also varies approximately ±50 mV across devices. D. Internal reference leakage during low ON time: Leakage resistance is on the order of 100 MΩ or more. This means the time constant is about 1000 s with 10-μF compensation capacitance. Since the REF voltage does not vary much, the reference comes up quickly after resuming from auto power down. At power up and power down the internal reference sees a glitch of about 500 μV when 2-V internal reference is used (1 mV when 4-V internal reference is used). This glitch settles out after about 50 μs. Figure 16. Reference Block Equivalent Circuit Power Down The device has three power-down modes. Autopower-Down Mode The device enters the autopower-down state at the end of a conversion. In autopower-down, the power consumption reduces to about 1 mA when an internal reference is selected. The built-in reference is still on to allow the device to resume quickly. The resumption is fast enough (within 0.5 SCLK) for use between cycles. An active CS, FS, or CSTART resumes the device from power-down state. The power current is 1 μA when an external reference is programmed and SCLK stops. Hardware/Software Power-Down Mode Writing 8000h to the device puts the device into a software power-down state, and the entire chip (including the built-in reference) is powered down. For a hardware power down, the dedicated PWDN pin provides another way to power down the device asynchronously. These two power-down modes power down the entire device including the built-in reference to save power. The power-down current is reduced to about 1 μA as the SCLK is stopped. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 17 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com An active CS, FS, or CSTART restores the device. There is no time delay when an external reference is selected. However, if an internal reference is used, it takes about 20 ms to warm up. Deselect PWDN pin to remove the device from the hardware power-down state. This requires about 20 ms to warm up if an internal reference is also selected. The configuration register is not affected by any of the power-down modes but the sweep operation sequence has to be started over again. All FIFO contents are cleared by the power-down modes. ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) Supply voltage range, GND to VCC Analog input voltage range UNIT –0.3 to 6.5 V –0.3 to VCC + 0.3 V VCC + 0.3 V Reference input voltage Digital input voltage range VALUE –0.3 to VCC + 0.3 V TJ Operating virtual junction temperature range –55 to 150 °C TA Operating free-air temperature range –55 to 125 °C Tstg Storage temperature range –65 to 150 °C 260 °C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds (1) Stresses beyond those listed under the 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 the recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. DISSIPATION RATINGS (1) PACKAGE TA < 25°C POWER RATING DERATING FACTOR ABOVE TA = 25°C (1) TA = 125°C POWER RATING 20 PW 977 mW 7.8 mW/°C 195 mW This is the inverse of the traditional junction-to-ambient thermal resistance (RθJA). Thermal resistance is not production tested and the values given are for informational purposes only. RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) VCC MIN NOM Supply voltage 3 3.3 Analog input voltage (1) 0 MAX UNIT 5.5 V VCC V VIH High level control input voltage VIL Low–level control input voltage td(CSL–FSH) Delay time, delay from CS falling edge to FS rising edge (see Figure 17). 0.5 SCLKs td(SCLK–CSH) Delay time, delay from 16th SCLK falling edge to CS rising edge (FS = 1), or 17th rising edge (FS is active) (see Figure 17 and Figure 20). 0.5 SCLKs tsu(FSH–SCLKL Setup time, FS rising edge before SCLK falling edge (see Figure 17). 20 ns th(FSH–SCLKL) Hold time, FS hold high after SCLK falling edge (see Figure 17). 30 ns twH(CS) Pulse width, CS high time (see Figure 17 and Figure 20). 100 ns twH(FS) Pulse width, FS high time (see Figure 17). tc(SCLK) SCLK cycle time (see Figure 17 and Figure 20). (1) 18 2.1 V 0.6 0.75 1 VCC = 3.0 V to 3.6 V 67 10000 VCC = 4.5 V to 5.5V 50 10000 V SCLKs ns When binary output format is used, analog input voltages greater than that applied to REFP convert as all ones (111111111111), while input voltages less than that applied to REFM convert as all zeros (000000000000). The device is functional with reference down to 1 V. (VREFP − VREFM − 1); however, the electrical specifications are no longer applicable. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 RECOMMENDED OPERATING CONDITIONS (continued) over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT VCC = 4.5 V 22 twL(SCLK) Pulse width, SCLK low time (see Figure 17 and Figure 20) VCC = 3.0 V 27 Pulse width, SCLK high time (see Figure 17 and Figure 20) VCC = 4.5 V 22 twH(SCLK) VCC = 3.0 V 27 tsu(DI–SCLK Setup time, SDI valid before falling edge of SCLK (FS is active) or the rising edge of SCLK (FS=1) (see and Figure 20). 25 ns th(DI–SCLK) Hold time, SDI hold valid after falling edge of SCLK (FS is active) or the rising edge of SCLK (FS=1) (see Figure 17). 5 ns td(CSL–DOV) Delay time, delay from CS falling edge to SDO valid (see Figure 17 and Figure 20). 25 ns td(FSL–DOV) Delay time, delay from FS falling edge to SDO valid (see Figure 17). 25 ns td(SCLK–DOV) Delay time, delay from SCLK falling edge (FS is VCC = 5.5 V active) or SCLK rising edge (FS=1) to SDO valid (see Figure 17 and Figure 20). For a date code later than VCC = 3.0 V xxx, see the Data Code Information section, item 3. SDO = 0 pF ns ns 0.5 SCLK + 5 SDO = 60 pF 0.5 SCLK + 24 SDO = 5 pF 0.5 SCLK + 12 ns SDO = 25 pF td(SCLK–EOCL) Delay time, delay from 17th SCLK rising edge (FS is active) or the 16th falling edge (FS=1) to EOC falling edge (see Figure 17 and Figure 20). td(SCLK–INTL) Delay time, delay from 16th SCLK falling edge to INT falling edge (FS =1) or from the 17th rising edge SCLK to INT falling edge (when FS active) (see Figure 20). td(CSL–INTH) or td(FSH–INTH) Delay time, delay from CS falling edge or FS rising edge to INT rising edge (see Figure 17, Figure 18, Figure 19 and Figure 20). td(CSH–CSTARTL) Delay time, delay from CS rising edge to CSTART falling edge (see Figure 18 and Figure 19). td(CSTARTH–EOCL) Delay time, delay from CSTART rising edge to EOC falling edge (see Figure 18 and Figure 19). twL(CSTART) Pulse width, CSTART low time (see Figure 18 and Figure 19). td(CSTARTH–CSTARTL) Delay time, delay from CSTART rising edge to CSTART falling edge (see Figure 19). td(CSTARTH–INTL) Delay time, delay from CSTART rising edge to INT falling edge (see Figure 18 and Figure 19). TA Operating free–air temperature 0.5 SCLK + 33 45 ns Min t(conv) µs 50 100 ns ns 50 ns Min t(sample) μs Max t(conv) μs μs Max t(conv) –55 125 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP °C 19 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com ELECTRICAL CHARACTERISTICS over operating free-air temperature range, VCC = VREFP = 3 V to 5.5 V, VREFM = 0 V, SCLK frequency = 20 MHz at 5 V, 15 MHz at 3 V (unless otherwise noted) PARAMETER TEST CONDITIONS VCC = 5.5 V, IOH = -0.2 mA at 30 pF load MIN TYP (1) MAX 2.4 UNIT VOH High–level output voltage VOL Low–level output voltage IOZ Off–state output current (high–impedance–state) VO = VCC CS = VCC VO = 0 CS = VCC IIH High–level input current VI = VCC 0.005 2.5 μA IIL Low–level input current VI = 0 V –0.005 2.5 μA VCC = 3.0 V, IOH = –20 μA at 30 pF load V VCC-0.2 VCC = 5.5 V, IOL = 0.8 mA at 30 pF load 0.4 VCC = 3.0 V, IOL = 20 μA at 30 pF load 0.1 CS at 0 V, Ext ref Operating supply current, normal short sampling CS at 0 V, Int ref ICC CS at 0 V, Ext ref Operating supply current, extended sampling CS at 0 V, Int ref 2.5 –2.5 VCC = 4.5 V to 5.5 V VCC = 3.0 V to 3.3 V 1 VCC = 4.5 V to 5.5 V 2.4 VCC = 3.0 V to 3.3 V 1.7 VCC = 4.5 V to 5.5 V 1.1 VCC = 3.0 V to 3.3 V 1 VCC = 4.5 V to 5.5 V 2.1 VCC = 3.0 V to 3.3 V 1.6 Power down supply current for all digital inputs, 0 ≤ VI ≤ 0.3 V or VI ≥ VCC - 0.3 V, SCLK = 0 VCC = 4.5 V to 5.5 V, Ext clock 1 VCC = 2.7 V to 3.3 V, Ext clock 1 VCC = 4.5 V to 5.5 V, Ext clock, Ext ref 1.0 (2) ICC(AUTOPWDN) Auto power–down current for all digital inputs, 0 ≤ VI ≤ 0.3 V or VI ≥ VCC - 0.3 V, SCLK = 0 VCC = 2.7 V to 3.3 V, Ext ref, Ext clock 1.0 (3) Selected channel leakage current Selected channel at VCC 2.5 Selected channel at 0 V 2.5 Ci Input capacitance Zi Input MUX ON resistance μA 2 ICC(PD) Maximum static analog reference current into REFP (use external reference) V VREFP = VCC = 5.5 V, VREFM = GND mA μA μA μA μA 1 Analog inputs 45 50 Control Inputs 5 25 VCC = 4.5 V 500 VCC = 2.7 V 600 pF Ω AC SPECIFICATIONS SINAD Signal-to-noise ratio + distortion fI = 12 kHz at 200 KSPS THD Total harmonic distortion fI = 12 kHz at 200 KSPS ENOB Effective number of bits fI = 12 kHz at 200 KSPS 11.6 SFDR Spurious free dynamic range fI = 12 kHz at 200 KSPS –84 65 71 dB TA = –55°C –82 –73 All other temperatures –82 –75 dB Bits –75 dB Analog Input (1) (2) (3) 20 Full-power bandwidth, –3 dB 1 MHz Full-power bandwidth, –1 dB 500 kHz All typical values are at VCC = 5 V, TA = 25°C. 1.2 mA if internal reference is used, 165 μA if internal clock is used. 0.8 mA if internal reference is used, 116 μA if internal clock is used. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 ELECTRICAL CHARACTERISTICS (continued) over operating free-air temperature range, VCC = VREFP = 3 V to 5.5 V, VREFM = 0 V, SCLK frequency = 20 MHz at 5 V, 15 MHz at 3 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP (1) MAX UNIT (4) REFERENCE SPECIFICATIONS (0.1 μF and 10 μF between REFP and REFM pins) REFP Positive reference input voltage VCC = 2.7 V to 5.5 V 2 VCC V REFM Negative reference input voltage VCC = 2.7 V to 5.5 V 0 2 V VCC = 5.5 V Reference Input impedance Reference Input voltage difference REFP-REFM Internal reference voltage (4) (5) 100 SCLK = 20 MHz CS = 0, (on) 20 CS = 1, SCLK = 0 (off) VCC = 2.7 V REFP-REFM CS = 1, SCLK = 0, (off) SCLK = 15 MHz CS = 0, (on) VCC = 2.7 V to 5.5 V MΩ 25 kΩ 100 20 MΩ 25 2 kΩ VCC VCC = 5.5 V VREF SELECT = 4 V 3.85 4 4.15 VCC = 5.5 V VREF SELECT = 2 V 1.925 2 2.075 VCC = 2.7 V VREF SELECT = 2 V 1.925 2 2.075 Internal reference start–up time VCC = 5.5 V, 2.7 V with 10 μF compensation cap 20 Internal reference temperature coefficient VCC = 2.7 V to 5.5 V 16 V V ms 40 (5) PPM/°C Specified by design. Specified by design. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 21 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com OPERATING CHARACTERISTICS over operating free-air temperature range, VCC = VREFP = 3 V to 5.5 V, VREFM = 0 V, SCLK frequency = 20 MHz at 5 V, 15 MHz at 3 V (unless otherwise noted) PARAMETER TEST CONDITIONS EL Integral linearity error (INL) ED Differential linearity error (DNL) EO Offset error EFS (4) Full scale error (4) Self–test output code MIN See (3) See (3) Conversion time t(sample) Sampling time (1) (2) (3) (4) (5) 22 (1) See (5) (3) MAX UNIT ±1.2 LSB ±1.2 LSB TA = 25°C and 125°C –4 6 TA = –55°C –4 6.2 TA = 25°C and 125°C –4 6 TA = –55°C –4 7.6 SDI = B000h 800h (2048D) SDI = C000h 000h (0D) SDI = D000h FFFh (4095D) Internal OSC t(conv) TYP (2) 3.2 (14 x DIV) / fSCLK External SCLK With a maximum of 1-kW input source impedance 600 LSB LSB 4.5 μs ns All typical values are at TA = 25°C. Linear error is the maximum deviation from the best straight line through the A/D transfer characteristics. Analog input voltages greater than that applied to REFP convert as all ones (111111111111), while input voltages less than that applied to REFM convert as all zeros (000000000000). Zero error is the difference between 000000000000 and the converted output for zero input voltage: full-scale error is the difference between 111111111111 and the converted output for full-scale input voltage. Both the input data and the output codes are expressed in positive logic. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 PARAMETER MEASUREMENT INFORMATION VIH CS VIL twH(CS) tWH(FS) td(CSL-FSH) VIH FS VIL th(FSH-SCLKL) td(CSL-INTH) twH(SCLK) td(SCLK-CSH) tc(SCLK) tsu(FSH-SCLKL) 1 td(FSH-INTH) 2 15 16 SCLK twL(SCLK) tsu(DI-SCLK) th(DI-SCLK) td(CSL-DOV) SDI ID15 ID14 VIH ID1 ID0 VIL td(FSL-DOV) Hi-Z SDO td(FSL-DOV) OD11 OD10 don’t care Hi-Z don’t care VOH OD15 VOL td(SCLK-EOCL) td(SCLK-DOV) t(conv) VOH EOC VOL td(SCLK-INTL) VOH INT VOL Figure 17. Critical Timing, DSP Mode (Normal Sampling, FS is Active) SELECT CYCLE VIH CS VIL td(CSH-CSTARTL) twL(CSTART) VIH CSTART † VIL td(CSTARTH-INTL) t(CONV) VOH EOC VOL td(CSTARTH-EOCL) td(CSL-INTH) INT VOH VOL † CSTART falling edge may come before the rising edge of CS but no sooner than the fifth SCLK of the SELECT CYCLE. Figure 18. Critical Timing (Extended Sampling, Single Shot) Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 23 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com PARAMETER MEASUREMENT INFORMATION (continued) SELECT CYCLE VIH CS twL(CSTART) VIL td(CSTARTHCSTARTL) td(CSH-CSTARTL) VIH CSTART VIL † VOH EOC td(CSL-INTH) td(CSTARTH-EOCL) VOL td(CSTARTH-INTL) VOH INT VOL † CSTART falling edge may come before the rising edge of CS but no sooner than the fifth SCLK of the SELECT CYCLE. In this case, the actual sampling time is measured from the rising edge CS to the rising edge of CSTART. Figure 19. Critical Timing (Extended Sampling, Repeat/Sweep/Repeat Sweep) VIH CS twH(CS) twH(SCLK) VIL td(SCLK-CSH) tc(SCLK) 1 2 15 16 VIH SCLK VIL twL(SCLK) tsu(DI-SCLK) th(DI-SCLK) SDI ID15 ID14 VIH ID1 ID0 VIL td(CSL-DOV) SDO Hi-Z OD11 OD10 don’t care VOH Hi-Z don’t care VOL td(SCLK-DOV) td(SCLK-EOCL) t(conv) VOH EOC VOL td(SCLK-INTL) td(CSL-INTH) VOH INT VOL Figure 20. Critical Timing, Microprocessor Mode (Normal Sampling, FS = 1) 24 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 TYPICAL CHARACTERISTICS INTEGRAL NONLINEARITY vs TEMPERATURE INTEGRAL NONLINEARITY vs TEMPERATURE 0.6 0.53 0.595 INL - Integral Nonlinearity - LSB INL - Integral Nonlinearity - LSB 0.52 0.51 0.5 0.49 0.48 VCC = 2.7 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.59 0.585 0.58 0.575 0.57 0.565 0.47 25 41.25 57.5 73.75 90 -40 -23.75 -7.5 8.75 TA - Temperature - °C VCC = 5.5 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.56 25 41.25 57.5 73.75 -40 -23.75 -7.5 8.75 TA - Temperature - °C Figure 21. Figure 22. DIFFERENTIAL NONLINEARITY vs TEMPERATURE DIFFERENTIAL NONLINEARITY vs TEMPERATURE 0.496 90 0.48 DNL - Differential Nonlinearity - LSB DNL - Differential Nonlinearity - LSB 0.494 0.492 0.49 0.488 0.486 0.484 0.482 VCC = 2.7 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.47 0.46 0.45 0.44 0.43 VCC = 5.5 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.48 0.478 25 41.25 57.5 73.75 -40 -23.75 -7.5 8.75 TA - Temperature - °C 90 0.42 25 41.25 57.5 73.75 -40 -23.75 -7.5 8.75 TA - Temperature - °C Figure 23. 90 Figure 24. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 25 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com TYPICAL CHARACTERISTICS (continued) GAIN ERROR vs TEMPERATURE 1.2 0.5 1 0 0.8 -0.5 Gain Error - LSB Offset Error - LSB OFFSET ERROR vs TEMPERATURE 0.6 0.4 0.2 VCC = 5 V, Internal Reference = 4 V, External Oscillator = SCLK/4, Single Shot, Long Sample, Mode 00 mP Mode 0 25 41.25 57.5 73.75 -40 -23.75 -7.5 8.75 TA - Temperature - °C VCC = 5 V, Internal Reference = 4 V, External Oscillator = SCLK/4, Single Shot, Long Sample, Mode 00 mP Mode -2.5 -40 -23.75 -7.5 8.75 25 41.25 57.5 73.75 TA - Temperature - °C 90 Figure 25. Figure 26. SUPPLY CURRENT vs TEMPERATURE POWER DOWN CURRENT vs TEMPERATURE External Reference = 4 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.2 VCC = 5 V Powerdown Current - mA 1.2 Short Sample 0.8 VCC = 5 V, External Reference = 4 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.6 -40 -23.75 -7.5 0 0.2 0.4 VCC = 2.7 V 0.6 VCC = 5.5 V 0.8 1 25 41.25 57.5 73.75 8.75 TA - Temperature - °C 90 25 41.25 57.5 73.75 -40 -23.75 -7.5 8.75 TA - Temperature - °C Figure 27. 26 90 0.4 Long Sample Supply Current - mA -1.5 -2 1.4 1 -1 90 Figure 28. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 TYPICAL CHARACTERISTICS (continued) INL - Integral Nonlinearity - LSB INTEGRAL NONLINEARITY vs SAMPLES 1.0 VCC = 2.7 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.5 0.0 -0.5 -1.0 0 Samples 4097 Figure 29. DNL - Differential Nonlinearity - LSB DIFFERENTIAL NONLINEARITY vs SAMPLES 1.0 VCC = 2.7 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.5 0.0 -0.5 -1.0 0 Samples 4097 Figure 30. INL - Integral Nonlinearity - LSB INTEGRAL NONLINEARITY vs SAMPLES 1.0 VCC = 5 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.5 0.0 -0.5 -1.0 0 Samples 4097 Figure 31. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 27 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com TYPICAL CHARACTERISTICS (continued) DNL - Differential Nonlinearity - LSB DIFFERENTIAL NONLINEARITY vs SAMPLES 1.0 VCC = 5 V, Internal Reference = 2 V, Internal Oscillator, Single Shot, Short Sample, Mode 00 mP Mode 0.5 0.0 -0.5 -1.0 0 4097 Samples Figure 32. Magnitude - dB MAGNITUDE vs FREQUENCY 100% 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 VCC = 5 V, External Reference = 4 V, Internal Oscillator , Single Shot, Long Sample, Mode 00 mP Mode @ 200 KSPS 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 f - Frequency - kHz Figure 33. 28 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 TYPICAL CHARACTERISTICS (continued) SIGNAL-TO-NOISE + DISTORTION vs INPUT FREQUENCY EFFECTIVE NUMBER OF BITS vs INPUT FREQUENCY ENOB - Effective Number of Bits - BITS -67.50 -68 -68.50 -69 -69.50 VCC = 5 V, External Reference = 4 V, Internal Oscillator, Single Shot, Long Sample, Mode 00 mP Mode -70 -70.50 -71 THD - Total Harmonic Distortion - dB 11.50 0 50 100 f - Frequency - kHz 11.40 11.30 11.20 11.10 10.90 0 Figure 35. TOTAL HARMONIC DISTORTION vs INPUT FREQUENCY SPURIOUS FREE DYNAMIC RANGE vs INPUT FREQUENCY -73 -70 -74 -71 -72 -73 -74 -75 VCC = 5 V, External Reference = 4 V, Internal Oscillator, Single Shot, Long Sample, Mode 00 mP Mode -77 -78 -79 0 50 100 f - Frequency - kHz Figure 34. -69 -76 VCC = 5 V, External Reference = 4 V, Internal Oscillator, Single Shot, Long Sample, Mode 00 mP Mode 11 10.80 150 Spurious Free Dynamic Range - dB SINAD - Signal-to-Noise + Distortion - dB -67 50 100 f - Frequency - kHz -75 -76 -77 -78 -79 VCC = 5 V, External Reference = 4 V, Internal Oscillator, Single Shot, Long Sample, Mode 00 mP Mode -80 -81 150 150 -82 0 Figure 36. 50 100 f - Frequency - kHz 150 Figure 37. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 29 TLV2548-EP SLAS668 – OCTOBER 2009 www.ti.com TYPICAL CHARACTERISTICS (continued) SIGNAL-TO-NOISE RATIO vs INPUT FREQUENCY SNR - Signal-to-Noise Ratio - dB -70.2 VCC = 5 V, External Reference = 4 V, Internal Oscillator, Single Shot, Long Sample, Mode 00 mP Mode -70.4 -70.6 -70.8 -71 -71.2 -71.4 0 50 100 f - Frequency - kHz Figure 38. 150 PRINCIPLES OF OPERATION vcc 10 kΩ VDD XF CS TXD SDI RXD SDO AIN CLKR CLKX TMS320 DSP BIO FSR FSX SCLK INT TLV2548 FS GND Figure 39. Typical Interface to a TMS320 DSP DATA CODE INFORMATION Parts with a date code earlier than 31xxxxx have the following discrepancies: 1. Earlier devices react to FS input irrespective of the state of the CS signal. 2. The earlier silicon was designed with SDO prereleased half clock ahead. This means in the microcontroller mode (FS=1) the SDO is changed on the rising edge of SCLK with a delay; and for DSP serial port (when FS is active) the SDO is changed on the falling edge of SCLK with a delay. This helps the setup time for processor input data, but may reduce the hold time for processor input data. It is recommended that a 100-pF capacitance be added to the SDO line of the ADC when interfacing with a slower processor that 30 Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP TLV2548-EP www.ti.com SLAS668 – OCTOBER 2009 requires longer input data hold time. 3. For earlier silicon, the delay time is specified as: MIN Delay time, delay from SCLK falling edge (FS is active) or SDO = 100 pF 20 ns SCLK rising edge (FS = 1) to next SDO valid, td(SCLK-DOV). VCC = 4.5 V VCC = 2.7 V SDO = 0 pF 16 SDO = 100 pF 20 SDO = 0 pF 24 SDO = 100 pF 30 NOM MAX UNIT ns This is because the SDO is changed at the rising edge in the up mode with a delay. This is the hold time required by the external digital host processor, therefore, a minimum value is specified. The newer silicon has been revised with SDO changed at the falling edge in the up mode with a delay. Since at least 0.5 SCLK exists as the hold time for the external host processor, the specified maximum value helps with the calculation of the setup time requirement of the external digital host processor. For an explanation of the DSP mode, reverse the rising/falling edges in item 2. above. Submit Documentation Feedback Copyright © 2009, Texas Instruments Incorporated Product Folder Link(s): TLV2548-EP 31 PACKAGE OPTION ADDENDUM www.ti.com 19-Mar-2011 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp TLV2548MPWREP ACTIVE TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM V62/10603-01XE ACTIVE TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM (3) Samples (Requires Login) (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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. 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