TSA1201

TSA1201 12-BIT, 50MSPS, 150mW A/D CONVERTER s 0.5Msps to 50Msps sampling frequency s 40mW @5Msps, 150mW @ 50Msps s 2.5V supply voltage with 2.5V/3.3V compatis s s s s bility for digital I/O Input range: 2Vpp differential SFDR up to 77dB @ 50Msps, Fin=15MHz ENOB up to10.5 bits @ 50Msps, Fin=15MHz Built-in reference voltage with external bias capability Pinout compatibility with TSA0801, TSA1001 and TSA1002 ORDER CODE Part Number TSA1201IF TSA1201IFT EVAL1201/AA Temperature Range -40°C to +85°C -40°C to +85°C Package TQFP48 TQFP48 Conditioning Tray Tape & Reel Marking SA1201I SA1201I Evaluation board PIN CONNECTIONS (top view) DESCRIPTION GNDBE VCCBE VCCBI AVCC AGND The TSA1201 is a 12-bit, 50MHz maximum sampling frequency Analog to Digital converter using a CMOS technology combining high performances and very low power consumption. The TSA1201 is based on a pipeline structure and digital error correction to provide excellent static linearity and achieve 10.5 effective bits at Fs=50Msps, and Fin=15MHz, with a global power consumption of 150mW. The TSA1201 features adaptative behaviour to the application. Its architecture allows to sample from 0.5Msps up to 50Msps, with a programmable power consumption which makes the application board even more optimized. It integrates a proprietary track-and-hold structure to ensure an high analog bandwidth of 1GHz and enable IF-sampling. Several features are available on the device. A voltage reference is integrated in the circuit. Differential or single-ended analog inputs can be applied. The output data can be coded into two differential formats. A Data Ready signal is raised as the data is valid on the output and can be used for synchronization purposes. The TSA1201 is available in extended (-40°C to +85°C) temperature range, in small 48 pins TQFP package. APPLICATIONS AVCC DFSB OEB SRC NC NC DR index corner 48 IPOL VREFP VREFM AGND VIN AGND VINB AGND INCM 1 2 3 4 5 6 7 8 9 47 46 45 44 43 42 41 40 39 38 37 36 NC 35 D0 (LSB) 34 D1 33 D2 32 D3 31 D4 TSA1201 30 D5 29 D6 28 D7 27 D8 26 D9 25 D10 AGND 10 AVCC 11 AVCC 12 13 14 15 16 17 18 19 20 21 22 23 24 DVCC DVCC DGND CLK DGND NC DGND GNDBI GNDBE VCCBE OR D11 (MSB) PACKAGE 7 x 7 mm TQFP48 s s s s s High speed data acquisition Medical imaging and ultrasound Portable instrumentation High speed DSP interface Digital communication - IF sampling 1/20 March 2001 TSA1201 ABSOLUTE MAXIMUM RATINGS Symbol AVCC DVCC VCCBI VCCBE Tstg ESD Analog Supply voltage Digital Supply voltage 1) Parameter Values 0 to 3.3 0 to 3.3 Unit V V V V °C KV 1) 1) Digital buffer Supply voltage 0 to 3.3 0 to 3.6 +150 2 1.5 Digital buffer Supply voltage 1) Storage temperature Electrical Static Discharge - HBM - CDM-JEDEC Standard 1. All voltages values, except differential voltage, are with respect to network ground terminal. The magnitude of input and output voltages must never exceed -0.3V or VCC+0V OPERATING CONDITIONS Symbol AVCC DVCC VCCBI VCCBE VREFP VREFM Parameter Analog Supply voltage Digital Supply voltage Internal (quiet) buffer Supply voltage External (noisy) buffer Supply voltage Forced top voltage reference Bottom internal reference voltage input Test conditions Min 2.25 2.25 2.25 2.25 0.8 0 Typ 2.5 2.5 2.5 2.5 Max 2.7 2.7 2.7 3.5 AVCC 1 Unit V V V V V V BLOCK DIAGRAM +2.5V +2.5V/3.3V VREFP GNDA VIN INCM VINB stage 1 stage 2 stage n Reference circuit IPOL VREFM DFSB Sequencer-phase shifting CLK SRC OEB Timing Digital data correction DR DO TO D11 OR GND Buffers 2/20 TSA1201 PIN CONNECTIONS (top view) GNDBE VCCBE VCCBI AVCC AGND AVCC DFSB OEB SRC DR NC NC index corner 48 IPOL VREFP VREFM AGND VIN AGND VINB AGND INCM AGND AVCC AVCC 1 2 3 4 5 6 7 8 9 10 11 12 13 47 46 45 44 43 42 41 40 39 38 37 36 NC 35 D0 (LSB) 34 D1 33 D2 32 D3 31 D4 TSA1201 30 D5 29 D6 28 D7 27 D8 26 D9 25 D10 14 15 16 17 18 19 20 21 22 23 24 DVCC DVCC DGND CLK DGND NC DGND GNDBI GNDBE VCCBE OR D11 (MSB) PIN DESCRIPTION Pin No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Name IPOL VREFP VREFM AGND VIN AGND VINB AGND INCM AGND AVCC AVCC DVCC DVCC DGND CLK DGND NC DGND GNDBI GNDBE VCCBE OR Description Analog bias current input Top voltage reference Bottom voltage reference Analog ground Analog input Analog ground Inverted analog input Analog ground Input common mode Analog ground Analog power supply Analog power supply Digital power supply Digital power supply Digital ground Clock input Digital ground Non connected Digital ground Digital buffer ground Digital buffer ground Digital buffer power supply Out Of Range output 0V 0V 0V 2.5V/3.3V CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) 1V 0V 0V 1Vpp 0V 1Vpp 0V 0.5V 0V 2.5V 2.5V 2.5V 2.5V 0V 2.5V compatible CMOS input 0V Observation Pin No 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Name D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0(LSB) NC NC DR VCCBE GNDBE VCCBI NC SRC OEB DFSB AVCC AVCC AGND Description Digital output Digital output Digital output Digital output Digital output Digital output Digital output Digital output Digital output Digital output Least Significant Bit output Non connected Non connected Data Ready output Digital Buffer power supply Digital Buffer ground Digital Buffer power supply Non connected Slew rate control input Output Enable input Data Format Select input Analog power supply Analog power supply Analog ground 2.5V/3.3V CMOS input 2.5V/3.3V CMOS input 2.5V/3.3V CMOS input 2.5V 2.5V 0V CMOS output (2.5V/3.3V) 2.5V/3.3V 0V 2.5V Observation CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) CMOS output (2.5V/3.3V) D11(MSB) Most Significant Bit output 3/20 TSA1201 ELECTRICAL CHARACTERISTICS AVCC = DVCC = VCCBE = VCCBI = 2.5V,Fs= 50Msps,Fin=2MHz, Vin@ -1dBFS, VREFM=0V Tamb = 25°C (unless otherwise specified) TIMING CHARACTERISTICS Symbol FS DC TC1 TC2 Tod Tpd Ton Toff Parameter Sampling Frequency Clock Duty Cycle Clock pulse width (high) Clock pulse width (low) Data Output Delay (Fall of Clock 6pF load capacitance to Data Valid) Data Pipeline delay Falling edge of OEB to digital output valid data Rising edge of OEB to digital output tri-state Test conditions Min 0.5 45 9 9 50 10 10 8 5.5 1 1 Typ Max 50 55 Unit MHz % ns ns ns cycles ns ns TIMING DIAGRAM N+2 N+1 N+3 N+4 N N-3 N-2 N-1 N+5 N+6 CLK Tpd + Tod OEB Tod Toff N-9 N-8 N-7 N-6 N-5 N-4 N-3 Ton N-1 N DATA OUT DR HZ state 4/20 TSA1201 CONDITIONS AVCC = DVCC = VCCBE = VCCBI = 2.5V,Fs= 50Msps,Fin=2MHz, Vin@ -1dBFS, VREFM=0V Tamb = 25°C (unless otherwise specified) ANALOG INPUTS Symbol Parameter Test conditions Min Typ 2.0 7.0 5 Vin@Full Scale, Fs=50Msps 1000 90 Max Unit Vpp pF MΩ MHz MHz VIN-VINB Full scale reference voltage Cin Rin BW ERB Input capacitance Differential input resistance Analog Input Bandwitdh Effective Resolution Bandwidth1) 1. See parameters definition for more information. REFERENCE VOLTAGE Symbol VREFP Parameter Top internal reference voltage Test conditions Min 0.79 Tmin= -40°C to Tmax= 85°C1) 0.79 1.08 Vpol Analog bias voltage Tmin= -40°C to Tmax= 85°C1) 1.07 0.40 VINCM Input common mode voltage Tmin= -40°C to Tmax= 85°C1) 0.4 0.55 1.15 Typ 1.0 Max 1.16 1.16 1.22 1.23 0.65 0.65 Unit V V V V V V 1. Not fully tested over the temperature range. Guaranted by sampling. 5/20 TSA1201 CONDITIONS AVCC = DVCC = VCCBE = VCCBI = 2.5V,Fs= 50Msps,Fin=2MHz, Vin@ -1dBFS, VREFP=1V, VREFM=0V Tamb = 25°C (unless otherwise specified) POWER CONSUMPTION Symbol Pd Parameter Power consumption in normal operation mode 1) Test conditions Min Typ 150 Max 158 165 Unit mW mW mA mA mA mA mA mA mA mA mA °C/W Tmin= -40°C to Tmax= 85°C2) 1) 46 85°C2) 1.9 51 55 2.2 2.2 ICCA Analog Supply current Tmin= -40°C to Tmax= 1) ICCD Digital Supply Current Tmin= -40°C to Tmax= 85°C2) 1) 0.3 0.4 0.4 ICCBI Digital Buffer Supply Current Tmin= -40°C to Tmax= 85°C2) 1) 9.8 2) 10.8 10.8 ICCBE Digital Buffer Supply Current Digital Buffer Supply Current in High Impedance Mode Junction-ambient thermal resistance (TQFP48) Tmin= -40°C to Tmax= 85°C ICCBEZ Rthja 4 80 5 1. Equivalent load: Rload= 470Ω and Cload= 6pF 2. Not fully tested over the temperature range. Guaranted by sampling. DIGITAL INPUTS AND OUTPUTS Symbol Clock input VIL VIH Logic "0" voltage Logic "1" voltage 2.0 0 2.5 0.8 V V Parameter Test conditions Min Typ Max Unit Digital inputs VIL VIH Logic "0" voltage Logic "1" voltage 0 0.75 x VCCBE VCCBE 0.25 x VCCBE V V Digital Outputs VOL VOH IOZ CL Logic "0" voltage Logic "1" voltage Iol=10µA Ioh=10µA 0 0.9 x VCCBE VCCBE -2.5 2.5 15 0.1 x VCCBE V V µA pF High Impedance leakage current OEB set to VIH Output Load Capacitance 6/20 TSA1201 CONDITIONS AVCC = DVCC = VCCBE = VCCBI = 2.5V,Fs= 50Msps, Vin@ -1dBFS, VREFP=1V, VREFM=0V Tamb = 25°C (unless otherwise specified) ACCURACY Symbol OE DNL INL Parameter Offset Error Differential Non Linearity Integral Non Linearity Monotonicity and no missing codes Test conditions Fin= 2MHz, VIN@+1dBFS Fin= 2MHz, VIN@+1dBFS Fin= 2MHz, VIN@+1dBFS Min Typ 2.45 ±0.6 ±1.7 Max Unit mV LSB LSB Guaranted DYNAMIC CHARACTERISTICS Symbol SFDR Parameter Spurious Free Dynamic Range Fin= 15MHz2) SNR Signal to Noise Ratio Fin= 15MHz1) Fin= 15MHz2) Fin= 15MHz1) THD Total Harmonics Distorsion Fin= 15MHz2) SINAD Signal to Noise and DistorsionRatio Fin= 15MHz1) Fin= 15MHz2) Fin= 15MHz1) ENOB Effective Number of Bits Fin= 15MHz2) 9.9 bits 61 60 10 10.5 64.4 -64 dB dB dB bits 61.6 60.7 -74.3 -68 64.9 -67 dBc dB dB dB Test conditions Fin= 15MHz1) Min Typ -77.2 Max -68 Unit dBc 1. Equivalent load: Rload= 470Ω and Cload= 6pF 2. Tmin= -40°C to Tmax= 85°C. Not fully tested over the temperature range. Guaranted by sampling. 7/20 TSA1201 DEFINITIONS OF SPECIFIED PARAMETERS STATIC PARAMETERS Static measurements are performed through method of histograms on a 2MHz input signal, sampled at 50Msps, which is high enough to fully characterize the test frequency response. The input level is +1dBFS to saturate the signal. Differential Non Linearity (DNL) The average deviation of any output code width from the ideal code width of 1LSB. Integral Non linearity (INL) An ideal converter presents a transfer function as being the straight line from the starting code to the ending code. The INL is the deviation for each transition from this ideal curve. DYNAMIC PARAMETERS Dynamic measurements are performed by spectral analysis, applied to an input sinewave of various frequencies and sampled at 50Msps. Spurious Free Dynamic Range (SFDR) The ratio between the power of the worst spurious signal (not always an harmonic) and the amplitude of fundamental tone (signal power) over the full Nyquist band. It is expressed in dBc. Total Harmonic Distortion (THD) The ratio of the rms sum of the first five harmonic distortion components to the rms value of the fundamental line. It is expressed in dB. Signal to Noise Ratio (SNR) The ratio of the rms value of the fundamental component to the rms sum of all other spectral components in the Nyquist band (f s/2) excluding DC, fundamental and the first five harmonics. SNR is reported in dB. Signal to Noise and Distorsion Ratio (SINAD) Similar ratio as for SNR but including the harmonic distortion components in the noise figure (not DC signal). It is expressed in dB. From the SINAD, the Effective Number of Bits (ENOB) can easily be deduced using the formula: SINAD= 6.02 × ENOB + 1.76 dB. When the applied signal is not Full Scale (FS), but has an A0 amplitude, the SINAD expression becomes: SINAD= 6.02 × ENOB + 1.76 dB + 20 log (2A0/FS) The ENOB is expressed in bits. Analog Input Bandwidth The maximum analog input frequency at which the spectral response of a full power signal is reduced by 3dB. Higher values can be achieved with smaller input levels. Effective Resolution Bandwidth (ERB) The band of input signal frequencies that the ADC is intended to convert without loosing linearity i.e. the maximum analog input frequency at which the SINAD is decreased by 3dB or the ENOB by 1/2 bit. Pipeline delay Delay between the initial sample of the analog input and the availability of the corresponding digital data output,on the output bus. Also called data latency. It is expressed as a number of clock cycles. 8/20 TSA1201 Static parameter: Integral Non Linearity Fs=50MSPS; Fin=1MHz; Icca=45mA; N=131072pts 3 2 1 INL (LSBs) 0 -1 -2 -3 0 500 1000 1500 2000 O u tp u t C o d e 2500 3000 3500 4000 Static parameter: Differential Non Linearity Fs=50MSPS; Fin=1MHz; Icca=45mA; N=131072pts 2 1 .5 1 0 .5 0 - 0 .5 -1 - 1 .5 -2 0 500 1000 1500 2000 O u tp u t C o d e 2500 3000 3500 4000 Linearity vs. VCCA Fs=50MSPS; Icca=45mA; Fin=10MHz 67 12 11.8 11.6 SNR SINAD DNL (LSBs) Distortion vs. VCCA Fs=50MSPS; Icca=45mA; Fin=10MHz -72 -73 -74 -75 -76 -77 -78 -79 -80 -81 -82 2.25 2.35 2.45 2.55 2.65 SFDR THD Dynamic parameters (dB) 66.5 66 65.5 65 64.5 64 63.5 63 62.5 62 2.25 2.35 2.45 2.55 2.65 ENOB 11.2 11 10.8 10.6 10.4 10.2 10 ENOB (bits) 11.4 Dynamic Parameters (dB) VCCA (V) VCCA (V) 9/20 TSA1201 Linearity vs. VCCD Fs=50MSPS; Icca=45mA; Fin=10MHz 66 12 11.8 SNR SINAD 11.6 11.4 11.2 11 10.8 10.6 ENOB 10.4 10.2 10 2.35 2.45 2.55 2.65 Distortion vs. VCCD Fs=50MSPS; Icca=45mA; Fin=10MHz -71 -73 -75 SFDR -77 -79 THD -81 -83 -85 2.25 2.35 2.45 2.55 2.65 Dynamic parameters (dB) 65.5 65 64.5 64 63.5 63 62.5 62 61.5 61 2.25 VCCD (V) Dynamic parameters (dB) ENOB (bits) VCCD (V) Linearity vs. VCCBE Fs=50MSPS; Icca=45mA; Fin=10MHz 66 12 SNR 11.8 11.6 SINAD Distortion vs. VCCBE Fs=50MSPS; Icca=45mA; Fin=10MHz -72 -73 -74 -75 -76 -77 -78 -79 -80 -81 -82 2.25 2.35 2.45 2.55 2.65 SFDR THD 65 64 63 62 61 60 2.25 2.35 ENOB 11.2 11 10.8 10.6 10.4 10.2 10 2.45 2.55 2.65 VCCBE (V) ENOB (bits) 11.4 Dynamic Parameters (dB) Dynamic parameters (dB) VCCBE (V) Linearity vs. Fs Icca=45mA; Fin=10MHz 70 12 SNR 11.5 ENOB (bits) SINAD 11 Distortion vs. Fs Icca=45mA; Fin=10MHz -50 Dynamic parameters (dB) 68 66 64 62 60 58 56 54 52 50 15 25 35 45 Dynamic parameters (dB) -55 -60 -65 -70 -75 -80 SFDR -85 -90 15 25 35 45 55 65 75 THD 10.5 ENOB 10 9.5 55 65 75 Fs (MHz) Fs (MHz) 10/20 TSA1201 Linearity vs. Fin Fs=50MHz; Icca=45mA 80 12 11.5 75 70 65 60 55 50 0 20 40 60 80 SNR ENOB 11 10.5 10 9.5 9 SINAD 8.5 8 7.5 7 Distortion vs. Fin Fs=50MHz; Icca=45mA -60 Dynamic parameters (dB) Dynamic parameters (dB) -65 -70 -75 -80 -85 -90 0 20 40 60 80 SFDR THD Fin (MHz) Fin (MHz) Linearity vs.Temperature Fs=49.7MSPS; Icca=45mA; Fin=15MHz 12 69 67 65 63 61 59 57 55 -40 10 60 110 Distortion vs. Temperature Fs=49.7MSPS; Icca=45mA; Fin=15MHz 90 Dynamic Parameters (dB) Dynamic Parameters (dB) 85 THD 80 75 SFDR 70 65 60 55 50 -40 10 60 110 11.5 SNR 11 SINAD 10.5 ENOB 10 9.5 Temperature (°C) Temperature (°C) Single-tone 16K FFT at 50Msps Fin=94.5MHz; Icca=45mA, Vin@-0.5dBFS 0 -20 -40 -60 -80 Power Spectrum (dB) -100 -120 -140 0 5 10 15 20 Frequency (MHz) 11/20 TSA1201 APPLICATION NOTE DETAILED INFORMATION The TSA1201 is a High Speed analog to digital converter based on a pipeline architecture and the latest deep submicron CMOS process to achieve the best performances in terms of linearity and power consumption. The pipeline structure consists of 11 internal conversion stages in which the analog signal is fed and sequencially converted into digital data. Each 10 first stages consists of an Analog to Digital converter, a Digital to Analog converter, a Sample and Hold and a gain of 2 amplifier. A 1.5-bit conversion resolution is achieved in each stage. The latest stage simply is a comparator. Each resulting LSB-MSB couple is then time shifted to recover from the delay caused by conversion. Digital data correction completes the processing by recovering from the redundancy of the (LSB-MSB) couple for each stage. The OPERATIONAL MODES DESCRIPTION Inputs Analog input differential level (VIN-VINB) > RANGE -RANGE > (VIN-VINB) RANGE> (VIN-VINB) >-RANGE (VIN-VINB) > RANGE -RANGE > (VIN-VINB) RANGE> (VIN-VINB) >-RANGE X X X Data Format Select (DFSB) When set to low level (VIL), the digital input DFSB provides a two’s complement digital output MSB. This can be of interest when performing some further signal processing. When set to high level (VIH), DFSB provides a standard binary output coding. DFSB OEB H H H L L L X X X L L L L L L H X X corrected data are outputed through the digital buffers. Signal input is sampled on the rising edge of the clock while digital outputs are delivered on the falling edge of the clock. The advantages of such a converter reside in the combination of pipeline architecture and the most advanced technologies. The highest dynamic performances are achieved while consumption remains at the lowest level. Some functionalites have been added in order to simplify as much as possible the application board. These operational modes are described in the following table. The TSA1201 is pin to pin compatible with the 8bits/40Msps TSA0801, the 10bits/25Msps TSA1001 and the 10bits/50Msps TSA1002. This ensures a conformity with the product family and above all, an easy upgrade of the application Outputs SRC X X X X X X X H L OR H H L H H L HZ X X DR CLK CLK CLK CLK CLK CLK HZ CLK CLK Most Significant Bit (MSB) D11 D11 D11 D11 Complemented D11 Complemented D11 Complemented HZ 25Msps compliant slew rate 50Msps compliant slew rate Output Enable (OEB) When set to low level (VIL), all digital outputs remain active and are in low impedance state. When set to high level (VIH), all digital outputs buffers are in high impedance state while the converter goes on sampling. When OEB is set to a low level again, the data are then present on the output with a very short Ton delay. Therefore, this allows the chip select of the device. The timing diagram summarizes this functionality. 12/20 TSA1201 Slew Rate Control (SRC) When set to high level (VIH), all digital outputs currents are limited to a clamp value so that digital noise power is reduced to its minimum. Rise and fall times just match 25MHz sampling rate assuming the load capacitance on each digital output remains below 10pF. When set to low level (VIL), the maximum digital output current increases so that rise and fall times just match the 50MHz sampling rate assuming the load capacitance on each digital output remains below 10pF. Out of Range (OR) This function is implemented on the output stage in order to set up an "Out of Range" flag whenever the digital data is over the full scale range. Typically, there is a detection of all the data being at ’0’ or all the data being at ’1’. This ends up with an output signal OR which is in low level state (VOL) when the data stay within in the range, or in high level state (VOH) when the data are out of the range. Data Ready (DR) The Data Ready output is an image of the clock being synchronized on the output data (D0 to D11). This is a very helpful signal that simplifes the synchronization of the measurement equipment or the controling DSP. As digital output, DR goes into high impedance state when OEB is asserted to high level as described in the timing diagram. DRIVING THE ANALOG INPUT Differential inputs The TSA1201 has been designed to obtain optimum performances when being differentially driven. An RF transformer is a good way to achieve such performances. Figure 1 describes the schematics. The input signal is fed to the primary of the transformer, while the secondary drives both ADC inputs. The common mode voltage of the ADC (INCM) is connected to the center-tap of the secondary of the transformer in order to bias the input signal around this common voltage, internally set to 0.56V. It determines the DC component of the analog signal. As being an high impedance input, it acts as an I/O and can be externally driven to adjust this DC component. The INCM is decoupled to maintain a low noise level on this node. Our evaluation board is mounted with a 1:1 ADT1-1 transformer from Minicircuits. You might Signal source 50Ω 100nF 330pF also use a higher impedance ratio (1:2 or 1:4) to reduce the driving requirement on the analog signal source. Each analog input can drive a 1Vpp amplitude input signal, so the resultant differential amplitude is 2Vpp. Figure 1 : D ifferential input configuration Analog source 50Ω ADT1-1 1:1 VIN 100pF TSA1201 VINB INCM 10nF 470nF Single-ended input configuration Some applications may require a single-ended input. This is easily achieved with the configuration reported on Figure 2 for an AC-coupled input or on Figure 3 and 4 for a DC-coupled input.. In the case of AC-coupled analog input, it is recommended to connect the other analog input to the common mode voltage of the circuit (INCM) so as to properly bias the ADC. The INCM may remain at the same internal level (0.56V) thus driving only a 1Vpp input amplitude, or it must be increased to 1V to drive a 2Vpp input amplitude. Figure 2 : AC-coupled Single-ended input VIN TSA1201 VINB INCM 330pF 10nF 470nF 1V In the case of DC-coupled analog input, Figure 3 shows the configuration for a 2Vpp input signal. The DC component is driven by VREFP which is connected to INCM and VINB and therefore imposes its voltage. VREFM being connected to ground, a dynamic of 2Vpp is achievable. Figure 4 describes the configuration for a 1Vpp analog signal. In this case, VREFM is connected 13/20 TSA1201 to VINB and INCM. The latest imposes its voltage. VREFP being internally set to 1V, the dynamic is then 1Vpp. Figure 3 : DC-coupled 2Vpp analog input REFERENCE CONNECTION Internal reference In the standard configuration, the ADC is biased with the internal reference voltage. VREFM pin is connected to Analog Ground while VREFP is internally set to a voltage of 1.0V. It is recommended to decouple the VREFP in order to minimize low and high frequency noise. Refer to Figure 5 for the schematics. Figure 5 : Internal reference setting 1.0V VIN VREFP 330pF 10nF 470nF Analog DC Analog+DC VIN VREFP TSA1201 VINB VREFM INCM 330pF 10nF 470nF Figure 4 : DC-coupled 1Vpp analog input TSA1201 VINB VREFM Analog DC Analog+DC VIN TSA1201 VINB VREFM INCM External reference It is possible to use an external reference voltage instead of the internal one for specific applications requiring even better linearity or enhanced temperature behaviour. In this case, the amplitude of the external voltage must be at least equal to the internal one (1.0V). Using the STMicroelectronics Vref TS821 leads to optimum performances when configured as shown on Figure 6. Figure 6 : External reference setting 330pF 10nF 470nF IF-sampling Software radio has become a common mode for receiving data through RF receivers. Its main advantage being to digitally implement what was originally done with analog functions such as discriminators, demodulation and filtering. Originally, bipolar process was mainly used because they provided high transistor transit frequency, while pure CMOS technology showed a lower one. With new CMOS process and circuit topology, higher frequencies are now achieved. The TSA1201 has been specifically designed to meet the requirement of sampling at Intermediate Frequency. For this purpose, the Track-and-Hold of the first pipeline stage has been built to ensure the global linearity of the overall ADC to perform the right characteristics. Our proprietary Track-and-Hold has a patented switch control system to enable the performances not to be degraded as input signal frequency increases. As a result, an analog bandwidth of 1GHz is achieved. 14/20 1kΩ 330pF 10nF 470nF VCCA VREFP VIN TSA1201 VINB VREFM TS821 external reference This can be very helpful for example for multichannel application to keep a good matching over the sampling frequency range. TSA1201 Clock input The quality of your converter is very dependant on your clock input accuracy, in terms of aperture jitter; the use of low jitter crystal controlled oscillator is recommended. The duty cycle must be between 45% and 55%. The clock power supplies must be separated from the ADC output ones to avoid digital noise modulation at the output. It is recommended to always keep the circuit clocked, even at the lowest specified sampling frequency of 0.5Msps, before applying the supply voltages. Power consumption optimization The internal architecture of the TSA1201 enables to optimize the power consumption according to the sampling frequency of. For this purpose, a resistor is placed between IPOL and the analog Ground pins. Therefore, the total dissipation is adjustable from 0.5Msps up to 50Msps. This feature is of highest importance when power saving conditions the application. The TSA1201 will combine highest performances and lowest consumption at 50Msps when Rpol is equal to 12kΩ. At lower sampling frequency range, this value of resistor may be adjusted in order to decrease the analog current without any degradation of dynamic performances. As an example, 40mW total power consumption is achieved at 5 Msps with Rpol equal to 190kΩ and 35mW is dissipated at 1Msps with Rpol equal to 350kΩ. The table below sums up the relevant data. Figure 7 describes the behaviour of the converter as sampling frequency increases and shows the optimum in terms of analog current and polarization resistor. Total power consumption optimization depending on Rpol value Fs (Msps) Rpol (kΩ) Optimized power (mW) 5 190 40 35 29 100 50 12 150 Rpol(kOhms) Figure 7 : Optimized power consumption Fin=1MHz 200 180 160 140 120 100 80 60 40 20 0 5 25 45 Fs(MHz) 65 85 RPOL ICCA 70 60 50 40 30 20 10 0 Icca(mA) Layout precautions To use the ADC circuits in the best manner at high frequencies, some precautions have to be taken for power supplies: - First of all, the implementation of 4 separate proper supplies and ground planes (analog, digital, internal and external buffer ones) on the PCB is mandatory for high speed circuit applications to provide low inductance and low resistance common return. The separation of the analog signal from the digital part is essential to prevent noise from coupling onto the input signal. - Power supply bypass capacitors must be placed as close as possible to the IC pins in order to improve high frequency bypassing and reduce harmonic distortion. - Proper termination of all inputs and outputs must be incorporated with output termination resistors; then the amplifier load will be only resistive and the stability of the amplifier will be improved. All leads must be wide and as short as possible especially for the analog input in order to decrease parasitic capacitance and inductance. - To keep the capacitive loading as low as possible at digital outputs, short lead lengths of routing are essential to minimize currents when the output changes. To minimize this output capacitance, buffers or latches close to the output pins will relax this constraint. - Choose component sizes as small as possible (SMD). 15/20 TSA1201 EVAL1201 evaluation board The characterization of the board has been made with a fully ADC devoted test bench as shown on Figure 8. The analog signal must be filtered to be very pure. The dataready signal is the acquisition clock of the logic analyzer. The ADC digital outputs are latched by the octal buffers 74LCX573. All characterization measurements have been made with: - SFSR=+0.5dB for static parameters. - SFSR=-0.5dB for dynamic parameters. Figure 8 : Analog to Digital Converter characterization bench Power HP8644B Sine wave Generator Vin ADC evaluation board ck data Logic Analyzer dataready TLA704 HP8133A Pulse Generator HP8644B Sine Wave Generator 16/20 J9 DFSB J11 1 2 1 2 1 1 2 VCCB2 C34 + J10 OEB J13 1 2 J17 VDDBUFF3V R10 47K R11 47K R12 47K R13 47K C16 AVCC 470nF C15 470nF C27 470nF C39 C28 VCCB1 47µ C37 2 Raj1 47K 10nF C14 R2 1K 330pF 330pF R14 R15 R16 R17 R18 R19 47K 47K 47K 47K 47K 47K 330pF 10nF C25 10nF C26 1 2 VrefP 1 2 J6 DR DO D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 5 1 2 VrefM C32 470nF AGND AVCC AVCC DFSB OEB NC NC 2.5VCCBUFF GNDBUFF 2.5VCCBUFF DR D0 10nF 330pF C31 C13 C12 C30 330pF 470nF 10nF C11 48 47 46 45 44 43 42 41 40 39 38 37 1 T2 6 Figure 9 : TSA1201 Evaluation board schematic 2 R1 R1 50 3 4 T2-AT1-1WT 8-14bits ADC TSA1002 TSA1201 74LCX573 C1 100pF 1 2 3 4 5 6 7 8 9 10 OEB VCC D0 Q0 D1 Q1 D2 Q2 D3 Q3 D4 Q4 U2 D5 Q5 D6 Q6 D7 Q7 GND LE 20 19 18 17 16 15 14 13 12 11 7 C10 C9 C8 1 2 C3 AVCC 470nF 10nF 330pF C4 C2 470nF 10nF 330pF Regl com mode 8 C7 C6 C5 1 2 13 14 15 16 17 18 19 20 21 22 23 24 Mes com Mode 12 DVCC DVCC DGND CLK DGND NC DGND GNDBUFF GNDBUFF 2.5VCCBUFF OR D13 470nF 10nF 330pF 1 2 3 4 5 6 7 8 9 10 11 12 Ipol VrefP VrefM AGND Vin AGND VINB AGND INCM AGND AVCC AVCC 1 2 3 4 5 6 7 8 9 10 OEB VCC D0 Q0 D1 Q1 U3 D2 Q2 D3 Q3 D4 Q4 D5 Q5 D6 Q6 D7 Q7 GND LE 74LCX573 C38 C29 6 2 4 + D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 20 19 18 17 16 15 14 13 12 11 36 35 34 33 32 31 30 29 28 27 26 25 2 1 AVCC + C42 47µF D13 OR 19 C20 330pF C21 1 R3 50 10nF C19 470nF C24 10µ + C41 10µF 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 470nF C40 10nF C33 330pF 32PIN 1 2 AGND 20 3 1 2 10nF C22 470nF C23 10µ + 10µF C17 T1 T2-AT1-1WT 330pF C18 DGND 21 1 2 GndB2 C36 47µ 2 1 J4 CLJ/SMB C35 47µ VCCB1 22 1 2 2 1 J15 DVCC J16 CON2 J18 VccB1 2 1 GndB1 TSA1201 17/20 TSA1201 Figure 10 : Printed circuit of evaluation board. Printed circuit board - List of components P a rt T yp e 10 uF 10 uF 10 uF 10 uF 10 0 p F 10 nF 10 nF 10 nF 10 nF 10 nF 10 nF 10 nF 10 nF 10 nF 10 nF 10 nF 1K Ω 3 2 P IN 3 3 0 pF 3 3 0 pF D e s ig n F o o t p rin t a to r C24 C23 C41 C29 C1 C 12 C39 C 15 C40 C27 C4 C21 C31 C6 C9 C 18 R2 J6 C25 C26 12 10 12 10 12 10 12 10 603 603 603 603 603 603 603 603 603 603 603 603 603 ID C 3 2 603 603 P a rt Typ e 33 0 pF 33 0 pF 33 0 pF 33 0 pF 33 0 pF 33 0 pF 33 0 pF 33 0 pF 33 0 pF 47 uF 47 uF 47 uF 47 uF 47 0 nF 47 0 nF 47 0 nF 47 0 nF 47 0 nF 47 0 nF 47 0 nF D e s ig n F o o t prin t a to r C33 C20 C8 C2 C5 C 11 C30 C 17 C 14 C36 C34 C35 C42 C22 C32 C37 C38 C 13 C28 C 10 603 603 603 603 603 603 603 603 603 CAP CAP CAP CAP 805 805 805 805 805 805 805 P a rt Typ e 4 70 nF 4 70 nF 4 70 nF 4 70 nF 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 4 7KΩ 50 Ω 50 Ω D e s ig n F o o t p rint ato r C7 C 16 C 19 C3 R 12 R 14 R 11 R a j1 R 10 R 19 R 13 R 15 R 16 R 17 R 18 R3 R1 805 805 805 805 603 603 603 VR 5 603 603 603 603 603 603 603 603 603 T S S OP 2 0 T S S OP 2 0 S IP 2 P a rt T yp e A VC C C LJ / S M B A GN D D FS B D GN D D VC C G n dB 1 G n dB 2 D e s ig n ato r J 12 J4 J 19 J9 J2 0 J 15 J2 2 J2 1 F IC H E2 M M SMB /H F IC H E2 M M F IC H E2 M M F IC H E2 M M F IC H E2 M M F IC H E2 M M F IC H E2 M M F IC H E2 M M F IC H E2 M M F IC H E2 M M ADT ADT F IC H E2 M M F IC H E2 M M SMB /H F IC H E2 M M F IC H E2 M M TQ F P 4 8 F o o t p rin t M e s c o m m o de J 8 O EB J 10 R e gl c o m m o de J7 T 2 - A T 1- 1WT T 2 - A T 1- 1WT Vc c B 1 VD D B UF F 3 V Vin Vre f M Vre f P T S A 10 0 TSA1201 2 T2 T1 J 18 J 17 J1 J5 J2 U1 7 4 LC X5 7 3 U3 7 4 LC X5 7 3 U2 CON2 J 16 18/20 TSA1201 PACKAGE MECHANICAL DATA 48 PINS - PLASTIC PACKAGE A A2 48 1 e A1 37 36 0,10 mm .004 inch SEATING PLANE 12 13 24 25 E3 E1 E D3 D1 D L1 L K Millimeters Dim. Min. A A1 A2 B C D D1 D3 e E E1 E3 L L1 K 0.05 1.35 0.17 0.09 Typ. Max. 1.60 0.15 1.45 0.27 0.20 0,25 mm .010 inch GAGE PLANE B c Inches Min. 0.002 0.053 0.007 0.004 Typ. Max. 0.063 0.006 0.057 0.011 0.008 1.40 0.22 9.00 7.00 5.50 0.50 9.00 7.00 5.50 0.60 1.00 0.055 0.009 0.354 0.276 0.216 0.0197 0.354 0.276 0.216 0.024 0.039 0.45 0.75 0.018 0.030 0° (min.), 7° (max.) Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. © The ST logo is a registered trademark of STMicroelectronics © 2001 STMicroelectronics - Printed in France - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom © http://www.st.com 19/20 TSA1201 20/20