HI5762 Data Sheet February 1999 Dual 10-Bit, 60MSPS A/D Converter with Internal Voltage Reference Features The HI5762 is a monolithic, dual 10-bit, 60MSPS analog-todigital converter fabricated in an advanced CMOS process. It is designed for high speed applications where integration, bandwidth and accuracy are essential. Built by combining two cores of the HI5767 single channel 10-bit 60MSPS analog-to-digital converter, the HI5762 reaches a new level of multi-channel integration. The fully pipeline architecture and an innovative input stage enable the HI5762 to accept a variety of input configurations, single-ended or fully differential. Only one external clock is necessary to drive both converters and an internal band-gap voltage reference is provided. This allows the system designer to realize an increased level of system integration resulting in decreased cost and power dissipation. • 8.8 Bits at fIN = 10MHz The HI5762 has excellent dynamic performance while consuming only 650mW of power at 60MSPS. The A/D only requires a single +5V power supply and encode clock. Data output latches are provided which present valid data to the output bus with a latency of 6 clock cycles. For those customers needing dual channel 8-bit resolution, please refer to the HI5662. For single channel 10-bit applications, please refer to the HI5767. Ordering Information • On-Chip Sample and Hold Amplifiers • Internal Band-Gap Voltage Reference . . . . . . . . . . . . 2.5V • Fully Differential or Single-Ended Analog Inputs • Single Supply Voltage Operation . . . . . . . . . . . . . . . . +5V • TTL/CMOS Compatible Sampling Clock Input • CMOS Compatible Digital Outputs . . . . . . . . . . . . 3.0/5.0V • Offset Binary Digital Data Output Format • Dual 10-Bit A/D Converters on a Monolithic Chip Applications • Wireless Local Loop • PSK and QAM I&Q Demodulators • Medical Imaging • High Speed Data Acquisition QVDC QIN- QIN+ AVCC1 VROUT NC VRIN 44 43 42 41 40 39 38 37 36 35 34 33 2 32 AVCC2 ID9 3 31 QD9 ID8 4 30 QD8 ID7 5 29 QD7 ID6 6 28 QD6 ID5 7 27 QD5 DVCC3 8 26 DVCC3 DGND 9 25 DGND ID4 10 24 QD4 ID3 11 23 12 13 14 15 16 17 18 19 20 21 22 QD3 AGND QD2 QD1 QD0 DGND DVCC2 CLK AVCC2 1 DVCC1 AGND 17 AGND Evaluation Platform IIN+ Q44.10x10 DGND 44 Ld MQFP HI5762 (MQFP) TOP VIEW PKG. NO. IIN- PACKAGE ID0 25 • Excellent Channel-to-Channel Isolation . . . . . . . . . >75dB IVDC HI5762EVAL2 • Wide Full Power Input Bandwidth. . . . . . . . . . . . . 250MHz Pinout TEMP. RANGE (oC) -40 to 85 • Low Power at 60MSPS. . . . . . . . . . . . . . . . . . . . . 650mW ID1 HI5762/6IN 4318.2 • Sampling Rate . . . . . . . . . . . . . . . . . . . . . . . . . . .60MSPS ID2 PART NUMBER File Number CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Copyright © Intersil Corporation 1999 HI5762 Functional Block Diagram I/QIN- I/QVDC BIAS I/QIN+ S/H STAGE 1 2-BIT FLASH 2-BIT DAC + ∑ DVCC3 X2 I/QD9 (MSB) I/QD8 I/QD7 I/QD6 DIGITAL DELAY AND DIGITAL ERROR CORRECTION STAGE 8 I/QD5 I/QD4 I/QD3 2-BIT FLASH 2-BIT DAC I/QD2 I/QD1 + ∑ I/QD0 (LSB) - X2 STAGE 9 2-BIT FLASH I or Q CHANNEL VREFOUT CLOCK REFERENCE VREFIN AVCC1,2 18 AGND DVCC1,2 DGND CLK HI5762 Typical Application Schematic HI5762 IIN + (42) IIN + (44) IVDC IIN - (43) IIN - QIN + (36) QIN + (34) QVDC QIN - (35) QIN - (40) VRIN (38) VROUT (LSB) ID0 (14) ID0 ID1 (13) ID1 ID2 (12) ID2 ID3 (11) ID3 ID4 (10) ID4 ID5 (7) ID5 ID6 (6) ID6 ID7 (5) ID7 ID8 (4) ID8 (MSB) ID9 (3) ID9 (LSB) QD0 (20) QD0 QD1 (21) QD1 QD2 (22) QD2 QD3 (23) QD3 QD4 (24) QD4 QD5 (27) QD5 QD6 (28) QD6 QD7 (29) QD7 QD8 (30) QD8 (MSB) QD9 (31) QD9 0.1µF CLK (17) CLOCK DVCC3 (8,26) + 10µF +5V or +3V 0.1µF + 10µF +5V 0.1µF (39) NC +5V + 10µF (37) AVCC1 DVCC2 (18) (2,32) AVCC2 DVCC1 (16) 0.1µF (1,33,41) AGND BNC AGND DGND 19 DGND (9,15,19,25) 10µF AND 0.1µF CAPS ARE PLACED AS CLOSE TO PART AS POSSIBLE HI5762 Pin Descriptions PIN NO. NAME 1 AGND 2 AVCC2 3 DESCRIPTION PIN NO. NAME Analog Ground 24 QD4 Analog Supply (+5.0V) 25 DGND Digital Ground ID9 I-Channel, Data Bit 9 Output (MSB) 26 DVCC3 4 ID8 I-Channel, Data Bit 8 Output Digital Output Supply (+3.0V or +5.0V) 5 ID7 I-Channel, Data Bit 7 Output 27 QD5 Q-Channel, Data Bit 5 Output 6 ID6 I-Channel Data Bit 6 Output 28 QD6 Q-Channel, Data Bit 6 Output 7 ID5 I-Channel, Data Bit 5 Output 29 QD7 Q-Channel, Data Bit 7 Output 8 DVCC3 30 QD8 Q-Channel, Data Bit 8 Output 31 QD9 Q-Channel, Data Bit 9 Output (MSB) 32 AVCC2 Analog Supply (+5.0V) 33 AGND Analog Ground 34 QVDC Q-Channel DC Bias Voltage Output 35 QIN- Q-Channel Negative Analog Input 36 QIN+ Q-Channel Positive Analog Input 37 AVCC1 Analog Supply (+5.0V) 38 VROUT +2.5V Reference Voltage Output 39 NC 40 VRIN +2.5V Reference Voltage Input 41 AGND Analog Ground 42 IIN+ I-Channel Positive Analog Input 43 IIN- I-Channel Negative Analog Input 44 IVDC Digital Output Supply (+3.0V or +5.0V) 9 DGND Digital Ground 10 ID4 I-Channel, Data Bit 4 Output 11 ID3 I-Channel, Data Bit 3 Output 12 ID2 I-Channel, Data Bit 2 Output 13 ID1 I-Channel, Data Bit 1 Output 14 ID0 I-Channel, Data Bit 0 Output (LSB) 15 DGND Digital Ground 16 DVCC1 Digital Supply (+5.0V) 17 CLK 18 DVCC2 Digital Supply (+5.0V) 19 DGND Digital Ground 20 QD0 Q-Channel, Data Bit 0 Output (LSB) 21 QD1 Q-Channel, Data Bit 1 Output 22 QD2 Q-Channel, Data Bit 2 Output 23 QD3 Q-Channel, Data Bit 3 Output Sample Clock Input 20 DESCRIPTION Q-Channel, Data Bit 4 Output No Connect I-Channel DC Bias Voltage Output HI5762 Absolute Maximum Ratings TA = 25oC Thermal Information Supply Voltage, AVCC or DVCC to AGND or DGND . . . . . . . . . . .6V DGND to AGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3V Digital I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DGND to DVCC Analog I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . AGND to AVCC Operating Conditions Thermal Resistance (Typical, Note 1) θJA (oC/W) HI5762/6IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . .150oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300oC (Lead Tips Only) Temperature Range HI5762/6IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTE: 1. θJA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications AVCC1,2 = DVCC1,2 = +5.0V, DVCC3 = +3.0V; VRIN = 2.50V; fS = 60MSPS at 50% Duty Cycle; CL = 10pF; TA = 25oC; Differential Analog Input; Unless Otherwise Specified PARAMETER TEST CONDITIONS MIN TYP MAX UNITS ACCURACY Resolution 10 - - Bits Integral Linearity Error, INL fIN = 10MHz - 2 - LSB Differential Linearity Error, DNL (Guaranteed No Missing Codes) fIN = 10MHz - ±0.4 ±1.0 LSB Offset Error, VOS fIN = DC -40 - +40 LSB Full Scale Error, FSE fIN = DC - 4 - LSB Minimum Conversion Rate No Missing Codes - 1 - MSPS Maximum Conversion Rate No Missing Codes 60 - - MSPS Effective Number of Bits, ENOB fIN = 10MHz 8.4 8.8 - Bits Signal to Noise and Distortion Ratio, SINAD RMS Signal = -------------------------------------------------------------RMS Noise + Distortion fIN = 10MHz - 54.7 - dB Signal to Noise Ratio, SNR RMS Signal = ------------------------------RMS Noise fIN = 10MHz - 54.7 - dB Total Harmonic Distortion, THD fIN = 10MHz - -68 - dBc 2nd Harmonic Distortion fIN = 10MHz - -70 - dBc 3rd Harmonic Distortion fIN = 10MHz - -73 - dBc Spurious Free Dynamic Range, SFDR fIN = 10MHz - 70 - dBc Intermodulation Distortion, IMD f1 = 1MHz, f2 = 1.02MHz - 64 - dBc I/Q Channel Crosstalk - -75 - dBc I/Q Channel Offset Match - 10 - LSB I/Q Channel Full Scale Error Match - 10 - LSB DYNAMIC CHARACTERISTICS Transient Response (Note 2) - 1 - Cycle Over-Voltage Recovery 0.2V Overdrive (Note 2) - 1 - Cycle Maximum Peak-to-Peak Differential Analog Input Range (VIN+ - VIN-) - ±0.5 - V Maximum Peak-to-Peak Single-Ended Analog Input Range - 1.0 - V - 1 - MΩ ANALOG INPUT Analog Input Resistance, RIN+ or RIN- 21 VIN+, VIN- = VREF, DC HI5762 Electrical Specifications AVCC1,2 = DVCC1,2 = +5.0V, DVCC3 = +3.0V; VRIN = 2.50V; fS = 60MSPS at 50% Duty Cycle; CL = 10pF; TA = 25oC; Differential Analog Input; Unless Otherwise Specified (Continued) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS - 10 - pF VIN+, VIN- = VREF-, VREF+,DC (Note 2, 3) -10 - 10 µA Differential Analog Input Bias Current IBDIFF = (IB+ - IB-) (Note 2, 3) -0.5 - +0.5 µA Full Power Input Bandwidth, FPBW (Note 2) - 250 - MHz Analog Input Common Mode Voltage Range (VIN+ + VIN-) / 2 Differential Mode (Note 2) 0.25 - 4.75 V 2.35 2.5 2.65 V Analog Input Capacitance, CIN+ or CIN- VIN+, VIN- = 2.5V, DC Analog Input Bias Current, IB+ or IB- INTERNAL VOLTAGE REFERENCE Reference Output Voltage, VROUT (Loaded) Reference Output Current, IROUT - 2 4 mA Reference Temperature Coefficient - -400 - ppm/oC REFERENCE VOLTAGE INPUT - 2.5 - V Total Reference Resistance, RRIN with VRIN = 2.5V - 1.25 - kΩ Reference Current, IRIN with VRIN = 2.5V - 2 - mA DC Bias Voltage Output, VDC - 3.0 - V Maximum Output Current - - 0.4 mA Reference Voltage Input, VRIN DC BIAS VOLTAGE SAMPLING CLOCK INPUT Input Logic High Voltage, VIH CLK 2.0 - - V Input Logic Low Voltage, VIL CLK - - 0.8 V Input Logic High Current, IIH CLK, VIH = 5V -10.0 - +10.0 µA Input Logic Low Current, IIL CLK, VIL = 0V -10.0 - +10.0 µA Input Capacitance, CIN CLK - 7 - pF DIGITAL OUTPUTS Output Logic High Voltage, VOH IOH = 100µA; DVCC3 = 5V 4.0 - - V Output Logic Low Voltage, VOL IOL = 100µA; DVCC3 = 5V - - 0.8 V Output Logic High Voltage, VOH IOH = 100µA; DVCC3 = 3V 2.4 - - V Output Logic Low Voltage, VOL IOL = 100µA; DVCC3 = 3V - - 0.5 V - 7 - pF Aperture Delay, tAP - 5 - ns Aperture Jitter, tAJ - 5 - psRMS Data Output Hold, tH - 10.7 - ns Data Output Delay, tOD - 11.7 - ns Output Capacitance, COUT TIMING CHARACTERISTICS Data Latency, tLAT For a Valid Sample (Note 2) 6 6 6 Cycles Power-Up Initialization Data Invalid Time (Note 2) - - 20 Cycles Sample Clock Pulse Width (Low) (Note 2) 7.5 8.3 - ns Sample Clock Pulse Width (High) (Note 2) 7.5 8.3 - ns - ±5 - % 4.75 5.0 5.25 V Sample Clock Duty Cycle Variation POWER SUPPLY CHARACTERISTICS Analog Supply Voltage, AVCC (Note 2) 22 HI5762 Electrical Specifications AVCC1,2 = DVCC1,2 = +5.0V, DVCC3 = +3.0V; VRIN = 2.50V; fS = 60MSPS at 50% Duty Cycle; CL = 10pF; TA = 25oC; Differential Analog Input; Unless Otherwise Specified (Continued) MIN TYP MAX UNITS Digital Supply Voltage, DVCC1 and DVCC2 PARAMETER (Note 2) TEST CONDITIONS 4.75 5.0 5.25 V Digital Output Supply Voltage, DVCC3 At 3.0V (Note 2) 2.7 3.0 3.3 V At 5.0V (Note 2) 4.75 5.0 5.25 V - 130 - mA - 650 670 mW Supply Current, ICC fS = 60MSPS Power Dissipation Offset Error Sensitivity, ∆VOS AVCC or DVCC = 5V ±5% - ±0.5 - LSB Gain Error Sensitivity, ∆FSE AVCC or DVCC = 5V ±5% - ±0.6 - LSB NOTES: 2. Parameter guaranteed by design or characterization and not production tested. 3. With the clock low and DC input. Timing Waveforms ANALOG INPUT CLOCK INPUT SN - 1 HN - 1 SN HN SN + 1 H N + 1 SN + 2 SN + 5 HN + 5 SN + 6 H N + 6 SN + 7 H N + 7 SN + 8 HN + 8 INPUT S/H 1ST STAGE 2ND STAGE B1 , N - 1 B2 , N - 2 9TH STAGE B1 , N B2 , N - 1 B9 , N - 5 DATA OUTPUT B1 , N + 1 B1 , N + 5 B2 , N + 4 B2 , N B9 , N - 4 DN - 6 B1 , N + 4 B9 , N DN - 5 B2 , N + 5 B9 , N + 1 DN - 1 tLAT NOTES: 4. SN : N-th sampling period. 5. HN : N-th holding period. 6. BM , N : M-th stage digital output corresponding to N-th sampled input. 7. DN : Final data output corresponding to N-th sampled input. FIGURE 1. HI5762 INTERNAL CIRCUIT TIMING 23 B1 , N + 6 B1 , N + 7 B2 , N + 6 B9 , N + 2 DN B9 , N + 3 DN + 1 DN + 2 HI5762 Timing Waveforms (Continued) ANALOG INPUT tAP tAJ CLOCK INPUT 1.5V 1.5V tOD tH 2.4V DATA OUTPUT DATA N DATA N-1 0.5V FIGURE 2. HI5762 INPUT-TO OUTPUT TIMING Typical Performance Curves 9 56 56 fS = 60MSPS TA = 25oC 50 50 7 44 44 38 100 38 6 1 10 SNR (dB) 8 SINAD (dB) ENOB (BITS) fS = 60MSPS TA = 25oC 1 10 INPUT FREQUENCY (MHz) FIGURE 3. EFFECTIVE NUMBER OF BITS (ENOB) AND SINAD vs INPUT FREQUENCY FIGURE 4. SNR vs INPUT FREQUENCY 90 70 fS = 60MSPS TA = 25oC 85 -2HD 100 INPUT FREQUENCY (MHz) 60 fS = 60MSPS fIN = 10MHz TA = 25oC 80 -3HD 50 70 dB dBc 75 40 65 -THD (dBc) -THD 60 30 SNR (dB) 55 50 SINAD (dB) 1 10 100 INPUT FREQUENCY (MHz) FIGURE 5. -THD, -2HD AND -3HD vs INPUT FREQUENCY 24 20 -40 -30 -20 -10 INPUT LEVEL (dBFS) FIGURE 6. SINAD, SNR AND -THD vs INPUT AMPLITUDE 0 HI5762 Typical Performance Curves (Continued) fS = 60MSPS 1MHz < fIN < 15MHz TA = 25oC ENOB (BITS) 8 7 6 5 40 42 44 46 48 50 52 54 56 58 60 SUPPLY CURRENT (mA) 9 150 140 1MHz < fIN < 15MHz 130 TA = 25oC 120 110 100 90 AICC 80 70 60 50 40 30 20 10 0 10 20 30 DUTY CYCLE (%, tHI /tCLK) ENOB (BITS) 8.0 7.5 -20 0 20 40 60 80 INTERNAL REFERENCE VOLTAGE, VROUT (V) fS = 60MSPS fIN = 10MHz 8.5 7.0 -40 40 50 DICC2 60 70 2.50 2.49 2.48 2.47 2.46 VROUT 2.45 2.44 2.43 2.42 2.41 2.40 -40 -20 0 TEMPERATURE (oC) 20 40 60 80 TEMPERATURE (oC) FIGURE 9. EFFECTIVE NUMBER OF BITS (ENOB) vs TEMPERATURE FIGURE 10. INTERNAL REFERENCE VOLTAGE (VROUT) vs TEMPERATURE 3.10 13.0 3.05 12.5 3.00 tOD (ns) DC BIAS VOLTAGE, I/QVDC (V) DICC3 FIGURE 8. SUPPLY CURRENT vs SAMPLE CLOCK FREQUENCY 9.0 I CHANNEL DICC1 fS (MSPS) FIGURE 7. EFFECTIVE NUMBER OF BITS (ENOB) vs SAMPLE CLOCK DUTY CYCLE Q CHANNEL ICC QVDC 2.95 tOD 12.0 IVDC 11.5 2.90 2.85 -40 -20 0 20 40 60 80 TEMPERATURE (oC) FIGURE 11. DC BIAS VOLTAGE (I/QVDC) vs TEMPERATURE 25 11.0 -40 -20 0 20 40 60 80 TEMPERATURE (oC) FIGURE 12. DATA OUTPUT DELAY (tOD) vs TEMPERATURE HI5762 Typical Performance Curves (Continued) 0 140 ICC fS = 60MSPS 1MHz < fIN < 15MHz -20 100 -30 -40 80 AICC dB SUPPLY CURRENT (mA) 120 fS = 60MSPS fIN = 10MHz TA = 25oC -10 60 -50 -60 -70 DICC1 40 -80 20 DICC2 DICC3 0 -40 -90 -100 -20 0 20 40 60 80 0 100 200 300 TEMPERATURE (oC) 400 500 600 700 800 900 1023 FREQUENCY (BIN) FIGURE 13. SUPPLY CURRENT vs TEMPERATURE FIGURE 14. 2048 POINT FFT PLOT TABLE 1. A/D CODE TABLE OFFSET BINARY OUTPUT CODE DIFFERENTIAL INPUT VOLTAGE (I/QIN+ - I/QIN-) CODE CENTER DESCRIPTION +Full Scale (+FS) -1/4 LSB +FS - 11/4 LSB +3/4 LSB -1/4 LSB -FS + 13/4 LSB -Full Scale (-FS) + 3/4 LSB MSB LSB I/QD9 I/QD8 I/QD7 I/QD6 I/QD5 I/QD4 I/QD3 I/QD2 I/QD1 I/QD0 0.499756V 1 1 1 1 1 1 1 1 1 1 0.498779V 1 1 1 1 1 1 1 1 1 0 732.422µV 1 0 0 0 0 0 0 0 0 0 -244.141µV 0 1 1 1 1 1 1 1 1 1 -0.498291V 0 0 0 0 0 0 0 0 0 1 -0.499268V 0 0 0 0 0 0 0 0 0 0 NOTE: 8. The voltages listed above represent the ideal center of each output code shown with VREFIN = +2.5V. Detailed Description Theory of Operation The HI5762 is a dual 10-bit fully differential sampling pipeline A/D converter with digital error correction logic. Figure 15 depicts the circuit for the front end differential-in-differentialout sample-and-hold (S/H) amplifiers. The switches are controlled by an internal sampling clock which is a nonoverlapping two phase signal, Φ1 and Φ2 , derived from the master sampling clock. During the sampling phase, Φ1 , the input signal is applied to the sampling capacitors, CS . At the same time the holding capacitors, CH , are discharged to analog ground. At the falling edge of Φ1 the input signal is sampled on the bottom plates of the sampling capacitors. In the next clock phase, Φ2 , the two bottom plates of the sampling capacitors are connected together and the holding capacitors are switched to the op amp output nodes. The charge then redistributes between CS and CH completing one sample-and-hold cycle. The front end sample-and-hold output is a fully-differential, sampled-data representation of the analog input. The circuit not only performs the sample-and- 26 hold function but will also convert a single-ended input to a fully-differential output for the converter core. During the sampling phase, the I/QIN pins see only the on-resistance of a switch and CS . The relatively small values of these components result in a typical full power input bandwidth of 250MHz for the converter. Φ1 I/QIN+ Φ1 Φ1 Φ1 CS Φ2 I/QIN- CH -+ VOUT+ +- VOUT- CS Φ1 CH Φ1 FIGURE 15. ANALOG INPUT SAMPLE-AND-HOLD HI5762 As illustrated in the functional block diagram and the timing diagram in Figure 1, eight identical pipeline subconverter stages, each containing a two-bit flash converter and a twobit multiplying digital-to-analog converter, follow the S/H circuit with the ninth stage being a two bit flash converter. Each converter stage in the pipeline will be sampling in one phase and amplifying in the other clock phase. Each individual subconverter clock signal is offset by 180 degrees from the previous stage clock signal resulting in alternate stages in the pipeline performing the same operation. The output of each of the eight identical two-bit subconverter stages is a two-bit digital word containing a supplementary bit to be used by the digital error correction logic. The output of each subconverter stage is input to a digital delay line which is controlled by the internal sampling clock. The function of the digital delay line is to time align the digital outputs of the eight identical two-bit subconverter stages with the corresponding output of the ninth stage flash converter before applying the eighteen bit result to the digital error correction logic. The digital error correction logic uses the supplementary bits to correct any error that may exist before generating the final ten bit digital data output of the converter. Because of the pipeline nature of this converter, the digital data representing an analog input sample is output to the digital data bus following the 6th cycle of the clock after the analog sample is taken (see the timing diagram in Figure 1). This time delay is specified as the data latency. After the data latency time, the digital data representing each succeeding analog sample is output during the following clock cycle. The digital output data is provided in offset binary format (see Table 1, A/D Code Table). Internal Reference Voltage Output, VREFOUT The HI5762 is equipped with an internal reference voltage generator, therefore, no external reference voltage is required. VROUT must be connected to VRIN when using the internal reference voltage. An internal band-gap reference voltage followed by an amplifier/buffer generates the precision +2.5V reference voltage used by the converter. A band-gap reference circuit is used to generate a precision +1.25V internal reference voltage. This voltage is then amplified by a wide-band uncompensated operational amplifier connected in a gain-of-two configuration. An external, user-supplied, 0.1µF capacitor connected from the VROUT output pin to analog ground is used to set the dominant pole and to maintain the stability of the operational amplifier. Reference Voltage Input, VREFIN The HI5762 is designed to accept a +2.5V reference voltage source at the VRIN input pin. Typical operation of the converter requires VRIN to be set at +2.5V. The HI5762 is tested with VRIN connected to VROUT yielding a fully differential analog input voltage range of ±0.5V. 27 The user does have the option of supplying an external +2.5V reference voltage. As a result of the high input impedance presented at the VRIN input pin, 1.25kΩ typically, the external reference voltage being used is only required to source 2mA of reference input current. In the situation where an external reference voltage will be used an external 0.1µF capacitor must be connected from the VROUT output pin to analog ground in order to maintain the stability of the internal operational amplifier. In order to minimize overall converter noise it is recommended that adequate high frequency decoupling be provided at the reference voltage input pin, VRIN . Analog Input, Differential Connection The analog input of the HI5762 is a differential input that can be configured in various ways depending on the signal source and the required level of performance. A fully differential connection (Figure 16 and Figure 17) will deliver the best performance from the converter. I/QIN+ VIN R HI5762 I/QVDC R -VIN I/QIN- FIGURE 16. AC COUPLED DIFFERENTIAL INPUT Since the HI5762 is powered by a single +5V analog supply, the analog input is limited to be between ground and +5V. For the differential input connection this implies the analog input common mode voltage can range from 0.25V to 4.75V. The performance of the ADC does not change significantly with the value of the analog input common mode voltage. A DC voltage source, I/QVDC , equal to 3.0V (typical), is made available to the user to help simplify circuit design when using an AC coupled differential input. This low output impedance voltage source is not designed to be a reference but makes an excellent DC bias source and stays well within the analog input common mode voltage range over temperature. For the AC coupled differential input (Figure 16) and with VRIN connected to VROUT, full scale is achieved when the VIN and -VIN input signals are 0.5VP-P, with -VIN being 180 degrees out of phase with VIN . The converter will be at positive full scale when the I/QIN+ input is at VDC + 0.25V and the I/QINinput is at VDC - 0.25V (I/QIN+ - I/QIN- = +0.5V). Conversely, the converter will be at negative full scale when the I/QIN+ input is equal to VDC - 0.25V and I/QIN- is at VDC + 0.25V (I/QIN+ - I/QIN- = -0.5V). HI5762 The analog input can be DC coupled (Figure 17) as long as the inputs are within the analog input common mode voltage range (0.25V ≤ VDC ≤ 4.75V). The resistors, R, in Figure 17 are not absolutely necessary but may be used as load setting resistors. A capacitor, C, connected from I/QIN+ to I/QIN- will help filter any high frequency noise on the inputs, also improving performance. Values around 20pF are sufficient and can be used on AC coupled inputs as well. Note, however, that the value of capacitor C chosen must take into account the highest frequency component of the analog input signal. VIN I/QIN+ VDC R C HI5762 I/QVDC R -VIN VDC I/QIN- FIGURE 17. DC COUPLED DIFFERENTIAL INPUT Analog Input, Single-Ended Connection The configuration shown in Figure 18 may be used with a single ended AC coupled input. The single ended analog input can be DC coupled (Figure 19) as long as the input is within the analog input common mode voltage range. VIN I/QIN+ VDC R HI5762 C VDC I/QIN- FIGURE 19. DC COUPLED SINGLE ENDED INPUT The resistor, R, in Figure 19 is not absolutely necessary but may be used as a load setting resistor. A capacitor, C, connected from I/QIN+ to I/QIN- will help filter any high frequency noise on the inputs, also improving performance. Values around 20pF are sufficient and can be used on AC coupled inputs as well. Note, however, that the value of capacitor C chosen must take into account the highest frequency component of the analog input signal. A single ended source may give better overall system performance if it is first converted to differential before driving the HI5762. Sampling Clock Requirements I/QIN+ VIN The HI5762 sampling clock input provides a standard highspeed interface to external TTL/CMOS logic families. R HI5762 VDC I/QIN- FIGURE 18. AC COUPLED SINGLE ENDED INPUT Again, with VRIN connected to VROUT, if VIN is a 1VP-P sinewave, then I/QIN+ is a 1.0VP-P sinewave riding on a positive voltage equal to VDC. The converter will be at positive full scale when I/QIN+ is at VDC + 0.5V (I/QIN+ - I/QIN- = +0.5V) and will be at negative full scale when I/QIN+ is equal to VDC - 0.5V (I/QIN+ - I/QIN- = -0.5V). Sufficient headroom must be provided such that the input voltage never goes above +5V or below AGND. In this case, VDC could range between 0.5V and 4.5V without a significant change in ADC performance. The simplest way to produce VDC is to use the DC bias source, I/QVDC, output of the HI5762. In order to ensure rated performance of the HI5762, the duty cycle of the clock should be held at 50% ±5%. It must also have low jitter and operate at standard TTL/CMOS levels. Performance of the HI5762 will only be guaranteed at conversion rates above 1MSPS (Typ). This ensures proper performance of the internal dynamic circuits. Similarly, when power is first applied to the converter, a maximum of 20 cycles at a sample rate above 1MSPS must be performed before valid data is available. Supply and Ground Considerations The HI5762 has separate analog and digital supply and ground pins to keep digital noise out of the analog signal path. The digital data outputs also have a separate supply pin, DVCC3 , which can be powered from a 3.0V or 5.0V supply. This allows the outputs to interface with 3.0V logic if so desired. The part should be mounted on a board that provides separate low impedance connections for the analog and digital supplies and grounds. For best performance, the supplies to the HI5762 should be driven by clean, linear regulated supplies. The board should also have good high frequency decoupling capacitors mounted as close as 28 HI5762 possible to the converter. If the part is powered off a single supply then the analog supply can be isolated by a ferrite bead from the digital supply. Refer to the application note “Using Intersil High Speed A/D Converters” (AN9214) for additional considerations when using high speed converters. Static Performance Definitions Offset Error (VOS) The midscale code transition should occur at a level 1/4 LSB above half-scale. Offset is defined as the deviation of the actual code transition from this point. Full-Scale Error (FSE) The last code transition should occur for an analog input that is 3/4 LSB below Positive Full Scale (+FS) with the offset error removed. Full scale error is defined as the deviation of the actual code transition from this point. Differential Linearity Error (DNL) DNL is the worst case deviation of a code width from the ideal value of 1LSB. Integral Linearity Error (INL) INL is the worst case deviation of a code center from a best fit straight line calculated from the measured data. Power Supply Sensitivity Each of the power supplies are moved plus and minus 5% and the shift in the offset and full scale error (in LSBs) is noted. Dynamic Performance Definitions Fast Fourier Transform (FFT) techniques are used to evaluate the dynamic performance of the HI5762. A low distortion sine wave is applied to the input, it is coherently sampled, and the output is stored in RAM. The data is then transformed into the frequency domain with an FFT and analyzed to evaluate the dynamic performance of the A/D. The sine wave input to the part is typically -0.5dB down from full scale for all these tests. SNR and SINAD are quoted in dB. The distortion numbers are quoted in dBc (decibels with respect to carrier) and DO NOT include any correction factors for normalizing to full scale. The Effective Number of Bits (ENOB) is calculated from the SINAD data by: ENOB = (SINAD - 1.76 + VCORR) / 6.02, where: VCORR = 0.5dB (Typ). VCORR adjusts the SINAD, and hence the ENOB, for the amount the analog input signal is backed off from full scale. 29 Signal To Noise and Distortion Ratio (SINAD) SINAD is the ratio of the measured RMS signal to RMS sum of all the other spectral components below the Nyquist frequency, fS/2, excluding DC. Signal To Noise Ratio (SNR) SNR is the ratio of the measured RMS signal to RMS noise at a specified input and sampling frequency. The noise is the RMS sum of all of the spectral components below fS /2 excluding the fundamental, the first five harmonics and DC. Total Harmonic Distortion (THD) THD is the ratio of the RMS sum of the first 5 harmonic components to the RMS value of the fundamental input signal. 2nd and 3rd Harmonic Distortion This is the ratio of the RMS value of the applicable harmonic component to the RMS value of the fundamental input signal. Spurious Free Dynamic Range (SFDR) SFDR is the ratio of the fundamental RMS amplitude to the RMS amplitude of the next largest spectral component in the spectrum below fS /2. Intermodulation Distortion (IMD) Nonlinearities in the signal path will tend to generate intermodulation products when two tones, f1 and f2 , are present at the inputs. The ratio of the measured signal to the distortion terms is calculated. The terms included in the calculation are (f1+f2), (f1-f2), (2f1), (2f2), (2f1+f2), (2f1-f2), (f1+2f2), (f1-2f2). The ADC is tested with each tone 6dB below full scale. Transient Response Transient response is measured by providing a full-scale transition to the analog input of the ADC and measuring the number of cycles it takes for the output code to settle within 10-bit accuracy. Over-Voltage Recovery Over-Voltage Recovery is measured by providing a full-scale transition to the analog input of the ADC which overdrives the input by 200mV, and measuring the number of cycles it takes for the output code to settle within 10-bit accuracy. Full Power Input Bandwidth (FPBW) Full power input bandwidth is the analog input frequency at which the amplitude of the digitally reconstructed output has decreased 3dB below the amplitude of the input sine wave. The input sine wave has an amplitude which swings from -FS to +FS. The bandwidth given is measured at the specified sampling frequency. HI5762 I/Q Channel Crosstalk Data Output Delay Time (tOD) I/Q Channel Crosstalk is a measure of the amount of channel separation or isolation between the two A/D converter cores contained within the dual converter package. The measurement consists of stimulating one channel of the converter with a fullscale input signal and then measuring the amount that signal is below, in dBc, a fullscale signal on the opposite channel. Data output delay time is the time to where the new data (N) is valid. Timing Definitions Refer to Figure 1 and Figure 2 for these definitions. Aperture Delay (tAP) Aperture delay is the time delay between the external sample command (the falling edge of the clock) and the time at which the signal is actually sampled. This delay is due to internal clock path propagation delays. Aperture Jitter (tAJ) Aperture jitter is the RMS variation in the aperture delay due to variation of internal clock path delays. Data Latency (tLAT) After the analog sample is taken, the digital data representing an analog input sample is output to the digital data bus following the 6th cycle of the clock after the analog sample is taken. This is due to the pipeline nature of the converter where the analog sample has to ripple through the internal subconverter stages. This delay is specified as the data latency. After the data latency time, the digital data representing each succeeding analog sample is output during the following clock cycle. The digital data lags the analog input sample by 6 sample clock cycles. Power-Up Initialization This time is defined as the maximum number of clock cycles that are required to initialize the converter at power-up. The requirement arises from the need to initialize the dynamic circuits within the converter. Data Hold Time (tH) Data hold time is the time to where the previous data (N - 1) is no longer valid. All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification. Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements 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 Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see web site http://www.intersil.com Sales Office Headquarters NORTH AMERICA Intersil Corporation P. O. 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