www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 FEATURES D Qualified for Automotive Applications D 3.3-V Single-Supply Operation D Dual Simultaneous Sample-and-Hold Inputs D Differential or Single-Ended Analog Inputs D Programmable Gain Amplifier: 0 dB to 18 dB D Separate Serial Control Interface D Single or Dual Parallel Bus Output D 60-dB SNR at fIN = 10.5 MHz D 73-dB SFDR at fIN = 10.5 MHz D Low Power: 275 mW D 300-MHz Analog Input Bandwidth D 3.3-V TTL/CMOS-Compatible Digital I/O D Internal or External Reference D Adjustable Reference Input Range D Power-Down (Standby) Mode D TQFP-48 Package APPLICATIONS D Digital Communications (Baseband Sampling) D Portable Instrumentation D Video Processing DESCRIPTION The ADS5204 is a dual 10-bit, 40 MSPS analog-to-digital converter (ADC). It simultaneously converts each analog input signal into a 10-bit, binary coded digital word up to a maximum sampling rate of 40 MSPS per channel. All digital inputs and outputs are 3.3-V TTL/CMOS compatible. An innovative dual pipeline architecture implemented in a CMOS process and the 3.3-V supply results in very low power dissipation. In order to provide maximum flexibility, both top and bottom voltage references can be set from user-supplied voltages. Alternatively, if no external references are available, the on-chip internal references can be used. Both ADCs share a common reference to improve offset and gain matching. If external reference voltage levels are available, the internal references can be powered down independently from the rest of the chip, resulting in even greater power savings. The ADS5204 also features dual, onboard programmable gain amplifiers (PGAs) that allow a setting of 0 dB to 18 dB to adjust the gain of each set of inputs in order to match the amplitude of the incoming signal. The ADS5204 is characterized for operation from −40°C to +85°C and is available in a TQFP-48 package. 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. !"#$ % &'!!($ #% )'*+&#$ ,#$(- !,'&$% &!" $ %)(&&#$% )(! $.( $(!"% (/#% %$!'"($% %$#,#!, 0#!!#$1- !,'&$ )!&(%%2 ,(% $ (&(%%#!+1 &+',( $(%$2 #++ )#!#"($(!%- Copyright 2008, Texas Instruments Incorporated www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. BLOCK DIAGRAM ORDERING INFORMATION{ PRODUCT PACKAGE−LEAD PACKAGE DESIGNATOR} SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ORDERING NUMBER TRANSPORT MEDIA, QUANTITY ADS5204 TQFP−48 PFB −40°C to +85°C AZ5204Q ADS5204IPFBRQ1 Tape and Reel, 1000 † 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 http://www.ti.com. ‡ Package drawings, thermal data, and symbolization are available at http://www.ti.com/packaging. ABSOLUTE MAXIMUM RATINGS ADS5204−Q1 AVDD to AGND, DVDD to DGND AVDD to DVDD, AGND to DGND −0.5 V to 3.6 V Supply voltage −0.5 V to 0.5 V Digital input voltage range to DGND −0.5 V to DVDD + 0.5 V Now Analog input voltage range to AGND −0.5 V to AVDD + 0.5 V Now Digital output voltage applied from Ext. Source to DGND −0.5 V to DVDD + 0.5 V VREFT, VREFB Reference voltage input range to AGND −0.5 V to AVDD + 0.5 V TA TSTG Operating free−air temperature range (ADS5204I −40°C to 85°C Storage temperature range −65°C to 150°C Now Soldering temperature 1,6 mm (1/16 inch) from case for 10 seconds 300°C (1) 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 “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 2 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range, TA, unless otherwise noted(1) PARAMETER CONDITIONS MIN NOM MAX UNIT 0 3.3 3.6 V POWER SUPPLY AVDD DVDD Supply voltage DRVDD ANALOG AND REFERENCE INPUTS VREFT VREFB Reference input voltage (top) VREFT–VREFB RREF Reference voltage differential Reference input resistance fCLK = 1 MHz to 80 MHz fCLK = 80 MHz IREF VIN Reference input current fCLK = 80 MHz VIN CI Analog input voltage, single−ended(1) Reference input voltage (bottom) fCLK = 1 MHz to 80 MHz fCLK = 1 MHz to 80 MHz Analog input voltage, differential 1.9 2 2.15 V 0.95 1 1.1 V 0.95 1 1.1 0.62 −1 mA 1 CML −1 Analog input capacitance Clock input(2) CML +1 8 0 V Ω 1650 V V pF AVDD V ANALOG OUTPUTS CML voltage AVDD/2 2.3 CML output resistance V kΩ DIGITAL INPUTS VIH VIL High-level input voltage 2.4 Low-level input voltage DGND Input capacitance tc (80 MHz) tw(CLKH), tw(CLKL) (80 MHz) 5 Clock period Pulse duration DVDD 0.8 Clock high or low tc (40 MHz) Clock period tw(CLKH),w(CLKL) t Pulse duration Clock high or low (40 MHz) (1) Applies only when the signal reference input connects to CML. (2) Clock pin is referenced to AVDD/AVSS. V V pF 12.5 ns 5.25 ns 25 ns 11.25 ns 3 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 ELECTRICAL CHARACTERISTICS over recommended operating conditions with fCLK = 80MHz and use of internal voltage references, and PGA Gain = 0dB, unless otherwise noted. MIN TYP MAX PARAMETER TEST CONDITIONS 64 72 IDD Operating Supply Current AVDD = DVDD = DRVDD = 3.3 V, CL = 10 pF, VIN = 3.5 MHz, −1 dBFS 1.7 2.2 18 27 PWDN_REF = ‘L’ 275 345 PWDN_REF = ‘H’ 240 300 STDBY = ‘H’, CLK Held HIGH or LOW 125 175 UNIT POWER SUPPLY AVDD DVDD DRVDD PD Power Dissipation PD(STBY) Standby Power tPD Power-up time for all references from standby tWU Wake-up time External Reference mA mW µW 550 ms 40 µs DIGITAL INPUTS IIH High-level input current on digital inputs include CLK IIL Low-level input current on digital inputs include CLK AVDD = DVDD = DRVDD = 3.6 V −1 1 µA −1 1 µA DIGITAL OUTPUTS VOH High−level output voltage AVDD = DVDD = DRVDD = 3 V at IOH = 50 µA, Digital outputs forced HIGH VOL Low-level output voltage AVDD = DVDD = DRVDD = 3 V at IOL = 50 µA, Digital outputs forced LOW CO Output capacitance IOZH High- impedance state output current to high level IOZL High-impedance state output current to low level Data output rise and fall time 2.8 2.96 0.04 V 0.2 V 1 µA 1 µA 5 AVDD = DVDD = DRVDD = 3.6 V −1 −1 pF CLOAD = 10 pF, Single-bus mode 3 ns CLOAD = 10 pF, Dual-bus mode 5 ns REFERENCE OUTPUTS VREFTO Reference top voltage VREFBO Reference bottom voltage REFT−REFB Differential reference voltage Absolute Min/Max values valid and tested for AVDD = 3.3 V 1.85 2 2.1 V 0.925 1 1.05 V 0.925 1.0 1.05 V DC ACCURACY INL Integral nonlinearity, end point . Internal references(1) TA = −40°C to 85°C −1.5 ±0.4 1.5 LSB DNL Differential nonlinearity Internal references(2) TA = −40°C to 85°C −0.9 ±0.4 1.0 LSB 0.12 ±1.5 %FS 0.28 ±1.5 %FS 0.24 ±1.5 %FS Missing codes No Missing Codes Assured Zero error(3) Full-scale error Gain error AVDD = DVDD = DRVDD = 3.3 V External References (3) (1) Integral nonlinearity refers to the deviation of each individual code from a line drawn from zero to full-scale. The point used as zero occurs 1/2 LSB before the first code transition. The full-scale point is defined as a level 1/2 LSB beyond the last code transition. The deviation is measured from the center of each particular code to the best-fit line between these two endpoints. (2) Integral nonlinearity refers to the deviation of each individual code from a line drawn from zero to full-scale. The point used as zero occurs 1/2 LSB before the first code transition. The full-scale point is defined as a level 1/2 LSB beyond the last code transition. The deviation is measured from the center of each particular code to the best-fit line between these two endpoints. (3) Zero error is defined as the difference in analog input voltage—between the ideal voltage and the actual voltage—that switches the ADC output from code 0 to code 1. The ideal voltage level is determined by adding the voltage corresponding to 1/2 LSB to the bottom reference level. The voltage corresponding to 1 LSB is found from the difference of top and bottom references divided by the number of ADC output levels (1024). Full-scale error is defined as the difference in analog input voltage—between the ideal voltage and the actual voltage—that switches the ADC output from code 1022 to code 1023. The ideal voltage level is determined by subtracting the voltage corresponding to 1.5 LSB from the top reference level. The voltage corresponding to 1 LSB is found from the difference of top and bottom references divided by the number of ADC output levels (1024). 4 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 DYNAMIC PERFORMANCE(1) TA = TMIN to TMAX, AVDD = DVDD = DRVDD = 3.3 V, fIN = −1 dBFS, Internal Reference, fCLK = 80 MHz, fS = 40 MSPS, Differential Input Range = 2 Vp−p, and PGA Gain = 0 dB, unless otherwise noted PARAMETER ENOB TEST CONDITIONS fIN = 3.5 MHz fIN = 10.5 MHz Effective number of bits MIN 9.3 fIN = 20 MHz fIN = 3.5 MHz THD SNR Total harmonic distortion Signal-to-noise ratio SFDR IMD UNIT Bits 9.7 Bits 9.6 Bits −71 dB −71 −68 dB fIN = 3.5 MHz fIN = 10.5 MHz 60.5 dB 60.5 dB 60 dB 60 dB 60 dB 60 dB 75 dB 73 dB fIN = 10.5 MHz fIN = 20 MHz Signal-to-noise ratio + distortion MAX 9.7 fIN = 10.5 MHz fIN = 20 MHz fIN = 20 MHz fIN = 3.5 MHz SINAD TYP 57 −63 dB Spurious-free dynamic range fIN = 3.5 MHz fIN = 10.5 MHz 70.5 dB Analog input bandwidth fIN = 20 MHz See Note (2) 300 MHz 2-Tone intermodulation distortion f1 = 9.5 MHz, f2 = 9.9 MHz −68 dBc 66 A/B channel crosstalk −75 A/B channel offset mismatch 0.016 dBc 1.75 % of FS A/B channel full-scale error mismatch 0.025 1 % of FS (1) These specifications refer to a 25-Ω series resistor and 15-pF differential capacitor between A/B+ and A/B− inputs; any source impedance brings the bandwidth down. (2) Analog input bandwidth is defined as the frequency at which the sampled input signal is 3 dB down on unity gain and is limited by the input switch impedance. PGA SPECIFICATIONS PARAMETER MIN TYP MAX UNIT Gain Range 0 to 18 dB Gain Step Size(1) 0.5826 dB Gain Error(2) Control Bits Per Channel −0.15 ±0.025 0.15 dB 5 Bits (1) See Table 2, PGA Gain Code. Ideal step size: 18.0618 dB / 31 = 0.5826 dB (2) Deviation from ideal. See Table 2, all gain settings. 5 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 PIN CONFIGURATION Terminal Functions TERMINAL NO. DRVDD 1,13 DRVSS 12, 24 DA 9..0 14-23 NAME I/O DESCRIPTION I I O Supply Voltage for Output Drivers 2-11 O Data Outputs for Bus B. D9 is MSB. This is the second bus. Data is output from the B channel when dual bus output mode is selected. The data outputs are in 3-state during power-down and single-bus modes (see the Timing Options table). 48 26 I O Output Enable. A low on this terminal will enable the data output bus, COUT and COUT. 25 44 43 47 O I I I Inverted Latch Clock control for the Data Outputs. COUT is in 3-state during power down. 45 27,37,41 I I Digital Supply Voltage REFT 29 28,36,40 35 34 31 I I I I I/O REFB 30 I/O Reference Voltage Bottom. The voltage at this terminal defines the bottom reference voltage for the ADC. Sufficient filtering should be applied to this input: the use of 0.1-µF capacitor between REFB and AVSS is recommended. Additionally, a 0.1-µF capacitor should be connected between REFT and REFB. CML 32 O Common-Mode Level. This voltage is equal to (AVDD − AVSS)/2. An external capacitor of 0.1µF should be connected between this terminal and AVSS when CML is used as a bias voltage. No capacitor is required if CML is not used. PDWN_REF 33 42 39 38 46 I I I I I Power-Down for Internal Reference Voltages. A HIGH on this terminal disables the internal reference circuit. DB 9..0 OE COUT COUT SDI DVSS CLK DVDD AVDD CS AVSS B− B+ STBY A− A+ SCLK 6 Digital Ground for Output Drivers Data Outputs for Bus A. D9 is MSB. This is the primary bus. Data from both input channels can be output on this bus or data from channel A only. The data outputs are in 3-state during power-down (see the Register Configuration table). Latch Clock for the Data Outputs. COUT is in 3-state during power down. Serial Data I/O Digital Ground Clock Input. The input is sampled on each rising edge of CLK when using a 40-MHz input and alternate rising edges when using an 80-MHz input. The clock pin is referenced to AVDD and AVSS to reduce noise coupling from digital logic. Analog Supply Voltage Serial Data Registers Chip Select Analog Ground Negative Input for the Analog B Channel Positive Input for the Analog B Channel Reference Voltage Top. The voltage at this terminal defines the top reference voltage for the ADC. Sufficient filtering should be applied to this input: the use of 0.1-µF capacitor between REFT and AVSS is highly recommended. Additionally a 0.1-µF capacitor should be connected between REFT and REFB. Standby Input. A high on this terminal powers down the device. Negative Input for the Analog A Channel Positive Input for Analog A Channel Serial Data Clock. Maximum clock rate is 20 MHz. www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 TIMING REQUIREMENTS PARAMETER fCLK TEST CONDITIONS MIN Input clock rate TYP MAX UNIT 80 MHz 1 Conversion rate 40 MSPS Clock duty cycle (40MHz) 45 1 50 55 % Clock duty cycle (80MHz) 42 50 58 % 9 14 ns 9 10.4 ns ns td(o) Output delay time ts(m) Mux setup time th(m) Mux hold time CL = 10 pF 1.7 2.1 ts(o) Output setup time CL = 10 pF 9 10.4 td(pipe) Pipeline delay (latency, channels A and B) MODE = 0, SELB = 0 8 CLK Cycles td(pipe) Pipeline delay (latency, channels A and B) MODE = 1, SELB = 0 4 CLK Cycles td(pipe) Pipeline delay (latency, channel A) MODE = 0, SELB = 1 8 CLK Cycles td(pipe) Pipeline delay (latency, channel B) MODE = 0, SELB = 1 9 CLK Cycles td(pipe) Pipeline delay (latency, channel A) MODE = 1, SELB = 1 8 CLK Cycles td(pipe) Pipeline delay (latency, channel B) MODE = 1, SELB = 1 9 CLK Cycles th(o) Output hold time CL = 10 pF td(a) Aperture delay time tJ(a) Aperture jitter tdis Disable time, OE rising to Hi-Z CL = 10 pF 1.5 ns 2.2 ns 3 ns 1.5 ten Enable T\time, OE falling to valid data (1) All internal operations are performed at a 40-MHz clock rate. ps, rms 5 8 ns 5 8 ns SERIAL INTERFACE TIMING PARAMETER MIN TYP MAX UNIT fSCLK Maximum Clock Rate 20 MHz tWH SCLK Pulse Width high 25 ns tWH SCLK Pulse Width low 25 ns tSU(CS_CK) Setup Time, CS low Before First Negative SCLK Edge tWH(CS) CS HIGH Width tSU(C16_CK) tSU(D) tSU(H) 5 ns 10 ns Setup Time, 16th Negative SCLK Edge before CS Rising Edge 5 ns Setup Time, Data Ready Before SCLK Falling Edge 5 ns Hold Time, Data Held Valid After SCLK Falling Edge 5 ns TIMING OPTIONS MODE SELB TIMING DIAGRAM FIGURE 80-MHz Input Clock, Dual-Bus Output, COUT = 40 MHz OPERATING MODE 0 0 1 40-MHz Input Clock, Dual-Bus Output, COUT = 40 MHz 1 0 2 80-MHz Input Clock, Single-Bus Output, COUT = 40 MHz 0 1 3 80-MHz Input Clock, Single-Bus Output, COUT = 80 MHz 1 1 4 7 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 TIMING DIAGRAMS Sample A1 and B1 Analog_A Analog_B 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 CLK(1) CLK40INT(2) td(pipe) ADCOUTA[9:0](3) A1 A2 A3 A4 A5 B1 td(o) B2 B3 B4 B5 td(pipe) ADCOUTB[9:0](3) DA[9:0] A1 A2 A3 A4 A5 B1 B2 B3 B4 B5 A&B 4 A&B 5 td(o) DB[9:0] DAB[19:0] is used to illustrate the placement of the busses DA and DB DAB[19:0] A&B 1 A&B 2 ts(o) th(o) A&B 3 COUT COUT (1) In this option CLK = 80 MHz. (2))CLK40INT refers to 40-MHz Internal Clock, per channel. (3))Internal signal only. Figure 1. Dual Bus Output—Option 1 Sample A1 and B1 Analog_A Analog_B 1 2 3 4 5 6 7 8 9 10 CLK(1) td(pipe) ADCOUTA[9:0](2) A1 A2 A3 A4 A5 B1 td(o) B2 B3 B4 B5 td(pipe) ADCOUTB[9:0](2) DA[9:0] A1 A2 A3 A4 A5 B1 B2 B3 B4 B5 A&B 3 A&B 4 A&B 5 td(o) DB[9:0] DAB[19:0] is used to illustrate the combined busses DA and DB DAB[19:0] A&B 1 A&B 2 ts(o) th(o) COUT COUT (1) In this option CLK = 40 MHz, per channel. (2))Internal signal only. Figure 2. Dual Bus Output—Option 2 8 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 Sample A1 and B1 Analog_A Analog_B 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 CLK(1) CLK40INT(2) td(pipe) ADCOUTA[9:0](3) A1 A2 A3 A4 A5 B1 td(o) B2 B3 B4 B5 td(pipe) ADCOUTB[9:0](3) td(o) DA[9:0] A1 B1 A2 B2 A3 B3 th(o) A4 B4 A5 B5 ts(o) COUT th(o) ts(o) COUT (1) In this option CLK = 80 MHz, per channel. (2))CLK40INT refers to 40-MHz internal Clock, per channel. (3))Internal signal only. Figure 3. Single Bus Output—Option 1 Sample A1 and B1 Analog_A Analog_B 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 CLK(1) CLK40INT(2) td(pipe) ADCOUTA[9:0](3) A1 A2 A3 A4 A5 B1 td(o) B2 B3 B4 B5 td(pipe) ADCOUTB[9:0](3) td(o) DA[9:0] A1 B1 th(o) A2 B2 A3 B3 A4 B4 A5 B5 ts(o) COUT ts(m) th(m) COUT (1) In this option CLK = 80 MHz. (2))CLK40INT refers to 40-MHz internal Clock, per channel. (3))Internal signal only. Figure 4. Single Bus Output—Option 2 9 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 t WH SCLK 1 t WH(CS) 2 t WL 3 4 15 16 t SU(CS_CK) t SU(C16_CS) CS t SU(D) t H(D) SDI D15 D14 D13 D12 D01 D00 Figure 5. Serial Data Write Table 1. Register Configuration 15 14 0 0 13 12 Reserved TWOS 11 10 MODE SELB 9 PGA4 B 8 PGA3 B 7 PGA2 B 6 PGA1 B 5 PGA0 B 4 PGA4 A 3 PGA3 A 2 PGA2 A 1 PGA1 A 0 PGA0 A Always write 0 Default (power up) condition for this register is all bits = 0. The user register is updated on either the first rising edge of SCLK after the 16th falling edge or CS rising, whichever comes first. Raising CS before 16 falling SCLK edges have been seen is an incomplete write error and no register update occurs. The PGA gain settings are resynchronized to the internal data conversion clock to avoid data glitches caused by changing gain settings while sampling the inputs. Note that only the PGA data is resynchronized. The TWOS, MODE, and SELB register bits take effect immediately after a successful register write. PGA gain control data is applied to the PGAs on the second falling edge of the ADC sample clock (CLK40INT) after a successful register write. This resynchronization ensures that no analog glitch occurs even when SCLK is asynchronous to CLK. 0 − Unsigned Binary 10 OUTPUT DATA FORMAT The output data format can either be in Binary Two’s Complement ouput mode or in unsigned binary mode, which affects both A and B channels. TWOS − Binary Two’s Complement Mode: 1 − Binary Two’s Complement Output. www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 Table 2. PGA DB[0:4], 5−bit PGA gain code for channel A or B GAIN (dB) PGx4 PGx3 PGx2 PGx1 PGx0 0 0 0 0 0 0 0.5606 0 0 0 0 1 1.1599 0 0 0 1 0 1.6643 0 0 0 1 1 2.3806 0 0 1 0 0 2.8703 0 0 1 0 1 3.5218 0 0 1 1 0 4.0824 0 0 1 1 1 4.6817 0 1 0 0 0 5.1630 0 1 0 0 1 5.8451 0 1 0 1 0 6.3903 0 1 0 1 1 6.9807 0 1 1 0 0 7.6040 0 1 1 0 1 8.0497 0 1 1 1 0 8.7712 0 1 1 1 1 9.2831 1 0 0 0 0 9.8272 1 0 0 0 1 10.4078 1 0 0 1 0 11.0301 1 0 0 1 1 11.7005 1 0 1 0 0 12.0412 1 0 1 0 1 12.7970 1 0 1 1 0 13.2208 1 0 1 1 1 14.0944 1 1 0 0 0 14.5400 1 1 0 0 1 15.0666 1 1 0 1 0 15.5630 1 1 0 1 1 16.1623 1 1 1 0 0 16.7229 1 1 1 0 1 17.4181 1 1 1 1 0 18.0618 1 1 1 1 1 11 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 TYPICAL CHARACTERISTICS At TA = 25°C, AVDD = DVDD = DRVDD = 3.3 V, fIN = −0.5 dBFS, Internal Reference, fCLK = 80 MHz, fS = 40 MSPS, Differential Input Range = 2 Vp-p, 25-Ω series resistor, and 15-pF differential capacitor at A/B+ and A/B− inputs, unless otherwise noted. 12 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 TYPICAL CHARACTERISTICS (Continued) At TA = 25°C, AVDD = DVDD = DRVDD = 3.3 V, fIN = −0.5 dBFS, Internal Reference, fCLK = 80 MHz, fS = 40 MSPS, Differential Input Range = 2 Vp-p, 25-Ω series resistor, and 15-pF differential capacitor at A/B+ and A/B− inputs, unless otherwise noted. 13 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 PRINCIPLE OF OPERATION The ADS5204 implements a dual high-speed 10-bit, 40MSPS converter in a cost-effective CMOS process. The differential inputs on each channel are sampled simultaneously. Signal inputs are differential and the clock signal is single-ended. The clock signal is either 80 MHz or 40 MHz, depending on the device configuration set by the user. Powered from 3.3 V, the dual-pipeline design architecture ensures low-power operation and 10-bit resolution. The digital inputs are 3.3-V TTL/CMOS compatible. Internal voltage references are included for both bottom and top voltages. Alternatively, the user may apply externally generated reference voltages. In doing so, the input range can be modified to suit the application. The ADC is a 5-stage pipelined ADC with four stages of fully-differential switched capacitor sub-ADC/MDAC pairs and a single sub-ADC in stage five. All stages deliver two bits of the final conversion result. A digital error correction is used to compensate for modest comparator offsets in the sub-ADCs. The analog input signal is sampled on capacitors CSP and CSN while the internal device clock is low. The sampled voltage is transferred to capacitors CHP and CHN and held on these while the internal device clock is high. The SHA can sample both single-ended and differential input signals. The load presented to the AIN pin consists of the switched input sampling capacitor CS (approximately 2 pF) and its various stray capacitances. A simplified equivalent circuit for the switched capacitor input is shown in Figure 7. The switched capacitor circuit is modeled as a resistor RIN. fCLK is the clock frequency, which is 40 MHz at full speed, and CS is the sampling capacitor. The use of 25-Ω series resistors and a differential 15-pF capacitor at the A/B+ and A/B− inputs is recommended to reduce noise. NOTE: AIN can be any variation of A or B inputs. fCLK = 40MHz SAMPLE-AND-HOLD AMPLIFIER Figure 6 shows the internal SHA/SHPGA architecture. The circuit is balanced and fully differential for good supply noise rejection. The sampling circuit has been kept as simple as possible to obtain good performance for high-frequency input signals. VCM VCM = 0.5 S (V(A/B+) + V(A/B−)) Figure 7. Equivalent Circuit for the Switched Capacitor Input ANALOG INPUT, DIFFERENTIAL CONNECTION Figure 6. SHA/SHPGA Architecture 14 The analog input of the ADS5204 is a differential architecture that can be configured in various ways depending on the signal source and the required level of performance. A fully differential connection will deliver the best performance from the converter. The analog inputs must not go below AVSS or above AVDD. The inputs can be biased with any common-mode voltage provided that the minimum and maximum input voltages stay within the range AVSS to AVDD. It is recommended to bias the inputs with a common-mode voltage around AVDD/2. This can be accomplished easily with the output voltage source CML, which is equal to AVDD/2. CML is made available to the user to help simplify circuit design. This output voltage source is not designed to be a reference or to be loaded but makes an excellent dc bias source and stays well within the analog input common-mode voltage range over temperature. www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 Table 3 lists the digital outputs for the corresponding analog input voltages. ADS5204 Table 3. Output Format for Differential Configuration DIFFERENTIAL INPUT VIN = (A/B+) – (A/B−), REFT − REFB = 1 V, PGA = 0 dB ANALOG INPUT VOLTAGE DIGITAL OUTPUT CODE VIN = +1 V VIN = 0 3FFH 200H VIN = −1 V 000H DC-COUPLED DIFFERENTIAL ANALOG INPUT CIRCUIT Driving the analog input differentially can be achieved in various ways. Figure 8 gives an example where a single-ended signal is converted into a differential signal by using a fully differential amplifier such as the THS4141. The input voltage applied to VOCM of the THS4141 shifts the output signal into the desired common-mode level. VOCM can be connected to CML of the ADS5204, the common-mode level is shifted to AVDD/2. ADS5204 Figure 9. AC-Coupled Differential Input with Transformer ANALOG INPUT, SINGLE-ENDED CONFIGURATION For a single-ended configuration, the input signal is applied to only one of the two inputs. The signal applied to the analog input must not go below AVSS or above AVDD. The inputs can be biased with any common-mode voltage provided that the minimum and maximum input voltage stays within the range AVSS to AVDD. It is recommended to bias the inputs with a common-mode voltage around AVDD/2. This can be accomplished easily with the output voltage source CML, which is equal to AVDD/2. An example for this is shown in Figure 10. ADS5204 Figure 8. Single-Ended to Differential Conversion Using the THS4141 AC-COUPLED DIFFERENTIAL ANALOG INPUT CIRCUIT Driving the analog input differentially can be achieved by using a transformer coupling, as illustrated in NO TAG. The center tap of the transformer is connected to the voltage source CML, which sets the common-mode voltage to AVDD/2. No buffer is required at the output of CML since the circuit is balanced and no current is drawn from CML. Figure 10. AC-Coupled, Single-Ended Configuration The signal amplitude to achieve full-scale is 2 Vp-p. The signal, which is applied at A/B+ is centered at the bias voltage. The input A/B− is also centered at the bias voltage. The CML output is connected via a 4.7-kΩ resistor to bias the input signal. There is a direct dc-coupling from CML to A/B− while this input is ac-decoupled through the 10-µF and 0.1-µF capacitors. The decoupling minimizes the coupling of A/B+ into the A/B− path. 15 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 Table 4 lists the digital outputs for the corresponding analog input voltages. Table 4. Output Format for Single-Ended Configuration SINGLE-ENDED INPUT, REFT − REFB = 1V, PGA = 0dB ANALOG INPUT VOLTAGE DIGITAL OUTPUT CODE V(A/B+) = VCML + 1V 3FFH 200H V(A/B+) = VCML V(A/B+) = VCML − 1V 000H REFERENCE TERMINALS The ADS5204’s input range is determined by the voltages on its REFB and REFT pins. The ADS5204 has an internal voltage reference generator that sets the ADC reference voltages REFB = 1 V and REFT = 2 V. The internal ADC references must be decoupled to the PCB AVSS plane. The recommended decoupling scheme is shown in Figure 11. The common-mode reference voltages should be 1.5 V for best ADC performance. DIGITAL INPUTS Digital inputs are CLK, SCLK, SDI, CS, STDBY, PWDN_REF, and OE. These inputs don’t have a pulldown resistor to ground, therefore, they should not be left floating. The CLK signal at high frequencies should be considered as an ‘analog’ input. CLK should be referenced to AVDD and AVSS to reduce noise coupling from the digital logic. Overshoot/undershoot should be minimized by proper termination of the signal close to the ADS5204. An important cause of performance degradation for a high-speed ADC is clock jitter. Clock jitter causes uncertainty in the sampling instant of the ADC, in addition to the inherent uncertainty on the sampling instant caused by the part itself, as specified by its aperture jitter. There is a theoretical relationship between the frequency (f) and resolution (2N) of a signal that needs to be sampled on one hand, and on the other hand the maximum amount of aperture error dtmax that is tolerable. It is given by the following relation: dtmax = 1/[π f 2(N+1)] ADS5204 As an example, for a 10-bit converter with a 20MHz input, the jitter needs to be kept less than 7.8ps in order not to have changes in the LSB of the ADC output due to the total aperture error. DIGITAL OUTPUTS Figure 11. Recommended External Decoupling for the Internal ADC Reference External ADC references can also be chosen. The ADS5204 internal references must be disabled by tying PWDN_REF high before applying the external reference sources to the REFT and REFB pins. The common-mode reference voltages should be 1.5 V for best ADC performance. ADS5204 Figure 12. External ADC Reference Configuration 16 The output of ADS5204 is an unsigned binary or Binary Two’s Complement code. Capacitive loading on the output should be kept as low as possible (a maximum loading of 10 pF is recommended) to ensure best performance. Higher output loading causes higher dynamic output currents and can, therefore, increase noise coupling into the part’s analog front end. To drive higher loads, the use of an output buffer is recommended. When clocking output data from ADS5204, it is important to observe its timing relation to COUT. See the Timing section for detailed information on the pipeline latency in the different modes. For safest system timing, COUT and COUT should be used to latch the output data (see Figure 1 through Figure 4). In Figure 4, COUT can be used by the receiving device to identify whether the data presently on the bus is from channel A or B. www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 LAYOUT, DECOUPLING, AND GROUNDING RULES Proper grounding and layout of the PCB on which the ADS5204 is populated is essential to achieve the stated performance. It is advised to use separate analog and digital ground planes that are spliced underneath the IC. The ADS5204 has digital and analog pins on opposite sides of the package to make this easier. Since there is no connection internally between analog and digital grounds, they have to be joined on the PCB. It is advised to do this at one point in close proximity to the ADS5204. As for power supplies, separate analog and digital supply pins are provided on the part (AVDD/DVDD). The supply to the digital output drivers is kept separate as well (DRVDD). Lowering the voltage on this supply to 3 V instead of the nominal 3.3 V improves performance because of the lower switching noise caused by the output buffers. Due to the high sampling rate and switched-capacitor architecture, the ADS5204 generates transients on the supply and reference lines. Proper decoupling of these lines is, therefore, essential. SERIAL INTERFACE A falling edge on CS enables the serial interface, allowing the 16-bit control register date to be shifted (MSB first) on subsequent falling edges of SCLK. The data is loaded into the control register on the first rising edge of SCLK after its 16th falling edge or CS rising, whichever occurs first. CS rising before 16 falling SCLK edges have been counted is an error and the control register will not be updated. The maximum update rate is: f UPDATEMAX + fSCLK + 20MHz + 1.25MHz 16 16 NOTES 1. Integral Nonlinearity (INL)—Integral nonlinearity refers to the deviation of each individual code from a line drawn from zero to full-scale. The point used as zero occurs 1/2 LSB before the first code transition. The full-scale point is defined as a level 1/2 LSB beyond the last code transition. The deviation is measured from the center of each particular code to the true straight line between these two endpoints. 2. Differential Nonlinearity (DNL)—An ideal ADC exhibits code transitions that are exactly 1 LSB apart. DNL is the deviation from this ideal value. Therefore, this measure indicates how uniform the transfer function step sizes are. The ideal step size is defined here as the step size for the device under test [ i.e. (last transition level − first transition level)/(2n − 2)]. Using this definition for DNL separates the effects of gain and offset error. A minimum DNL better than –1LSB ensures no missing codes. 3. Zero and Full-Scale Error—Zero error is defined as the difference in analog input voltage—between the ideal voltage and the actual voltage—that switches the ADC output from code 0 to code 1. The ideal voltage level is determined by adding the voltage corresponding to 1/5 LSB to the bottom reference level. The voltage corresponding to 1 LSB is found from the difference of top and bottom references divided by the number of ADC output levels (1024). Full-scale error is defined as the difference in analog input voltage—between the ideal voltage and the actual voltage—that switches the ADC output from code 1022 to code 1023. The ideal voltage level is determined by subtracting the voltage corresponding to 1. 5LSB from the top reference level. The voltage corresponding to 1 LSB is found from the difference of top and bottom references divided by the number of ADC output levels (1024). 4. Analog Input Bandwidth—The analog input bandwidth is defined as the max. frequency of a 1-dBFS input sine that can be applied to the device for which an extra 3-dB attenuation is observed in the reconstructed output signal. 5. Output Timing—Output timing td(o) is measured from the 1.5-V level of the CLK input falling edge to the 10%/90% level of the digital output. The digital output load is not higher than 10 pF. Output hold time th(o) is measured from the 1.5-V level of the COUT input rising edge to the 10%/90% level of the digital output. The digital output is load is not less than 2 pF. Aperture delay td(A) is measured from the 1.5-V level of the CLK input to the actual sampling instant. The OE signal is asynchronous. OE timing tdis is measured from the VIH(MIN) level of OE to the highimpedance state of the output data. The digital output load is not higher than 10 pF. OE timing ten is measured from the VIL(MAX) level of OE to the instant when the output data reaches VOH(min) or VOL(max) output levels. The digital output load is not higher than 10 pF. 6. Pipeline Delay (latency)—The number of clock cycles between conversion initiation on an input sample and the corresponding output data being made available from the ADC pipeline. Once the data pipeline is full, new valid output data is provided on every clock cycle. The first valid data is available on the output pins after the latency time plus the output delay time td(o) through the digital output buffers. Note that a minimum td(o) is not assured because data can transition before or after a CLK edge. It is possible to use CLK for latching data, but at the risk of the prop delay varying over temperature, causing data to transition one CLK cycle 17 www.ti.com SGLS271A − OCTOBER 2004 − REVISED JUNE 2008 earlier or later. The recommended method is to use the latch signals COUT and COUT which are designed to provide reliable setup and hold times with respect to the data out. 7. Wake-Up Time—Wake-up time is from the power-down state to accurate ADC samples being taken and is specified for external reference sources applied to the device and an 80-MHz clock applied at the time of release of STDBY. Cells that need to power up are the bandgap, bias generator, SHAs, and ADCs. 18 8. Power-Up Time—Power-up time is from the power-down state to accurate ADC samples being taken with an 80-MHz clock applied at the time of release of STDBY. Cells that need to power up are the bandgap, internal reference circuit, bias generator, SHAs, and ADCs. PACKAGE OPTION ADDENDUM www.ti.com 11-Mar-2011 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) ADS5204IPFBRG4Q1 ACTIVE TQFP PFB 48 1000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR ADS5204IPFBRQ1 ACTIVE TQFP PFB 48 1000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR 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. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. 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OTHER QUALIFIED VERSIONS OF ADS5204-Q1 : • Catalog: ADS5204 NOTE: Qualified Version Definitions: Addendum-Page 1 PACKAGE OPTION ADDENDUM www.ti.com 11-Mar-2011 • Catalog - TI's standard catalog product Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant ADS5204IPFBRG4Q1 TQFP PFB 48 1000 330.0 16.4 9.6 9.6 1.5 12.0 16.0 Q2 ADS5204IPFBRQ1 TQFP PFB 48 1000 330.0 16.4 9.6 9.6 1.5 12.0 16.0 Q2 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) ADS5204IPFBRG4Q1 TQFP PFB 48 1000 367.0 367.0 38.0 ADS5204IPFBRQ1 TQFP PFB 48 1000 367.0 367.0 38.0 Pack Materials-Page 2 MECHANICAL DATA MTQF019A – JANUARY 1995 – REVISED JANUARY 1998 PFB (S-PQFP-G48) PLASTIC QUAD FLATPACK 0,27 0,17 0,50 36 0,08 M 25 37 24 48 13 0,13 NOM 1 12 5,50 TYP 7,20 SQ 6,80 9,20 SQ 8,80 Gage Plane 0,25 0,05 MIN 0°– 7° 1,05 0,95 Seating Plane 0,75 0,45 0,08 1,20 MAX 4073176 / B 10/96 NOTES: A. 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