SIGNS NEW DE R O F D E ND M ENT C OM M E EPL ACE R D E NO T R E D nter at OMMEN pport Ce m/tsc u S l NO REC a ic n tersil.co our Tech contact ERSIL or www.in Data March 31, 2005 88-INT 1-8Sheet HI5805 FN3984.7 12-Bit, 5MSPS A/D Converter Features The HI5805 is a monolithic, 12-bit, Analog-to-Digital Converter fabricated in Intersil’s HBC10 BiCMOS process. It is designed for high speed, high resolution applications where wide bandwidth and low power consumption are essential. • Sampling Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5MSPS The HI5805 is designed in a fully differential pipelined architecture with a front end differential-in-differential-out sample-and-hold (S/H). The HI5805 has excellent dynamic performance while consuming 300mW power at 5MSPS. • Full Power Input Bandwidth . . . . . . . . . . . . . . . . . 100MHz The 100MHz full power input bandwidth is ideal for communication systems and document scanner applications. Data output latches are provided which present valid data to the output bus with a latency of 3 clock cycles. The digital outputs have a separate supply pin which can be powered from a 3.0V to 5.0V supply. • TTL/CMOS Compatible Digital I/O SAMPLE RATE TEMP. RANGE (oC) HI5805BIB 5MSPS -40 to 85 28 Ld SOIC (W) M28.3 HI5805BIBZ (See Note) 5MSPS -40 to 85 28 Ld SOIC (W) M28.3 (Pb-free) HI5805EVAL1 25 PACKAGE PKG. DWG. # Evaluation Board NOTE: Intersil Pb-free products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 1 • Internal Sample and Hold • Fully Differential Architecture • Low Distortion • Internal Voltage Reference • Digital Outputs . . . . . . . . . . . . . . . . . . . . . . . . . 5V to 3.0V • Pb-Free Available (RoHS Compliant) Applications • Digital Communication Systems Ordering Information PART NUMBER • Low Power • Undersampling Digital IF • Document Scanners • Additional Reference Documents - AN9214 Using Intersil High Speed A/D Converters - AN9707 Using the HI5805EVAL1 Evaluation Board Pinout HI5805 (SOIC) TOP VIEW CLK 1 28 D0 DVCC1 2 27 D1 DGND1 3 26 D2 DVCC1 4 25 D3 DGND1 5 24 D4 AVCC 6 23 D5 AGND 7 VIN+ 8 22 DVCC2 21 DGND2 VIN- 9 20 D6 VDC 10 19 D7 VROUT 11 18 D8 VRIN 12 17 D9 AGND 13 16 D10 AVCC 14 15 D11 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-352-6832 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2000, 2005. All Rights Reserved All other trademarks mentioned are the property of their respective owners. HI5805 Functional Block Diagram VDC VINVIN+ BIAS CLOCK CLK VROUT VRIN REF S/H STAGE 1 DVCC2 4-BIT FLASH 4-BIT DAC + D11 (MSB) X8 D10 DIGITAL DELAY AND DIGITAL ERROR CORRECTION - STAGE 3 4-BIT FLASH 4-BIT DAC + - D9 D8 D7 D6 D5 D4 D3 D2 D1 X8 D0 (LSB) STAGE 4 4-BIT FLASH AGND AVCC DGND2 DVCC1 DGND1 Typical Application Schematic (LSB) (28) D0 (27) D1 VROUT (11) (26) D2 (25) D3 VRIN (12) (24) D4 AGND (7) (23) D5 AGND (13) (20) D6 DGND1 (3) (19) D7 DGND1 (5) (18) D8 DGND2 (21) (17) D9 (16) D10 (MSB) (15) D11 VIN+ (8) VDC (10) (2) DVCC1 VIN- VIN- (9) (22) DVCC2 CLK (1) BNC D11 +5V 0.1F + 10F 0.1F +5V + 10F (6) AVCC (14) AVCC HI5805 2 AGND DGND (4) DVCC1 VIN+ CLOCK D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 10F AND 0.1F CAPS ARE PLACED AS CLOSE TO PART AS POSSIBLE HI5805 Absolute Maximum Ratings Thermal Information Supply Voltage, AVCC or DVCC to AGND or DGND . . . . . . . . . +6.0V DGND to AGND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3V Digital I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DGND to DVCC Analog I/O Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AGND to AVCC Thermal Resistance (Typical, Note 1) JA (oC/W) SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . .150oC Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering, 10s). . . . . . . . . . . . .300oC (SOIC - Lead Tips Only) Operating Conditions Temperature Range, HI5805BIB . . . . . . . . . . . . . . . . -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. JA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications AVCC = DVCC1 = DVCC2 = DVCC3 = +5.0V, fS = 5MSPS at 50% Duty Cycle, VRIN = 3.5V, CL = 10pF, TA = -40oC to 85oC, Differential Analog Input, Typical Values are Test Results at 25oC, Unless Otherwise Specified HI5805BIB (-40oC TO 85oC) PARAMETER TEST CONDITION MIN TYP MAX UNITS 12 - - Bits ACCURACY Resolution Integral Linearity Error, INL fIN = DC - 1 2 LSB Differential Linearity Error, DNL (Guaranteed No Missing Codes) fIN = DC - 0.5 1 LSB Offset Error, VOS fIN = DC - 19 - LSB Full Scale Error, FSE fIN = DC - 32 - LSB DYNAMIC CHARACTERISTICS Minimum Conversion Rate No Missing Codes - 0.5 - MSPS Maximum Conversion Rate No Missing Codes 5 - - MSPS Effective Number of Bits, ENOB fIN = 1MHz 10.0 11 - Bits Signal to Noise and Distortion Ratio, SINAD fIN = 1MHz - 68 - dB fIN = 1MHz - 68 - dB Total Harmonic Distortion, THD fIN = 1MHz - -80 - dBc 2nd Harmonic Distortion fIN = 1MHz - -86 3rd Harmonic Distortion fIN = 1MHz - -83 - dBc Spurious Free Dynamic Range, SFDR fIN = 1MHz - 83 - dBc Intermodulation Distortion, IMD f1 = 1MHz, f2 = 1.02MHz RMS Signal = -------------------------------------------------------------RMS Noise + Distortion Signal to Noise Ratio, SNR RMS Signal = ------------------------------RMS Noise Transient Response Over-Voltage Recovery 0.2V Overdrive dBc - -68 - dBc - 1 - Cycle - 2 - Cycle - 2.0 - V ANALOG INPUT Maximum Peak-to-Peak Differential Analog Input Range (VIN+ - VIN-) Maximum Peak-to-Peak Single-Ended Analog Input Range (Notes 2, 3) Analog Input Resistance, RIN Analog Input Capacitance, CIN Analog Input Bias Current, IB+ or IB- 4.0 - V - - M - 10 - pF A -10 - +10 Differential Analog Input Bias Current IB DIFF = (IB+ - IB-) - 0.5 - A Full Power Input Bandwidth, FPBW - 100 - MHz 3 (Note 3) 1 HI5805 Electrical Specifications AVCC = DVCC1 = DVCC2 = DVCC3 = +5.0V, fS = 5MSPS at 50% Duty Cycle, VRIN = 3.5V, CL = 10pF, TA = -40oC to 85oC, Differential Analog Input, Typical Values are Test Results at 25oC, Unless Otherwise Specified (Continued) HI5805BIB (-40oC TO 85oC) PARAMETER TEST CONDITION MIN TYP MAX UNITS 1 2.3 4 V Reference Output Voltage, VROUT (Loaded) - 3.5 - V Reference Output Current - - 1 mA Reference Temperature Coefficient - 200 - ppm/oC - 3.5 - V Analog Input Common Mode Voltage Range (VIN+ + VIN-)/2 Differential Mode (Note 2) INTERNAL VOLTAGE REFERENCE REFERENCE VOLTAGE INPUT Reference Voltage Input, VRIN Total Reference Resistance, RL - 7.8 - k Reference Current - 450 - A DC Bias Voltage Output, VDC - 2.3 - V Max Output Current (Not To Exceed) - - 1 mA Input Logic High Voltage, VIH 2.0 - - V Input Logic Low Voltage, VIL - - 0.8 V - 10.0 A DC BIAS VOLTAGE DIGITAL INPUTS (CLK) Input Logic High Current, IIH VCLK = 5V - Input Logic Low Current, IIL VCLK = 0V - - 10.0 A - 7 - pF 1.6 - - mA Input Capacitance, CIN DIGITAL OUTPUTS (D0-D11) Output Logic Sink Current, IOL VO = 0.4V (Note 2) Output Logic Source Current, IOH VO = 2.4V (Note 2) DVCC3 = 3.0V, VO = 0.4V - 1.6 - mA -0.2 - - mA - -0.2 - mA - 5 - pF Aperture Delay, tAP - 5 - ns Aperture Jitter, tAJ - 5 - ps (RMS) Data Output Delay, tOD - 8 - ns Data Output Hold, t H - 8 - ns Cycles DVCC3 = 3.0V, VO = 2.4V Output Capacitance, COUT TIMING CHARACTERISTICS Data Latency, tLAT For a Valid Sample (Note 2) - - 3 Clock Pulse Width (Low) 5MSPS Clock 90 100 110 ns Clock Pulse Width (High) 5MSPS Clock 90 100 110 ns POWER SUPPLY CHARACTERISTICS Total Supply Current, ICC VIN+ - VIN- = 2V - 60 70 mA Analog Supply Current, AICC VIN+ - VIN- = 2V - 46 - mA Digital Supply Current, DICC1 VIN+ - VIN- = 2V - 13 - mA Output Supply Current, DICC2 VIN+ - VIN- = 2V - 1 - mA Power Dissipation VIN+ - VIN- = 2V - 300 350 mW Offset Error PSRR, VOS AVCC or DVCC = 5V 5% - 2 - LSB Gain Error PSRR, FSE AVCC or DVCC = 5V5% - 30 - LSB NOTES: 2. Parameter guaranteed by design or characterization and not production tested. 3. With the clock off (clock low, hold mode). 4 HI5805 Timing Waveforms ANALOG INPUT CLOCK INPUT SN-1 HN - 1 SN HN S N + 1 HN + 1 SN + 2 HN + 2 S N + 3 HN + 3 SN+4 HN + 4 SN + 5 H N + 5 SN + 6 HN + 6 INPUT S/H 1ST STAGE 2ND STAGE B1, N - 1 B2, N - 2 3RD STAGE 4TH STAGE B1, N B2, N - 1 B3, N - 2 B4, N - 3 DATA OUTPUT B1, N + 1 B2, N B3, N - 1 B4, N - 2 DN - 3 B1, N + 2 B2, N + 1 B3, N B4, N - 1 DN - 2 B2, N + 2 B3, N + 1 B4, N DN - 1 B1, N + 3 B2, N + 3 B3, N + 2 B4, N + 1 DN B4, N + 2 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. INTERNAL CIRCUIT TIMING ANALOG INPUT tAP tAJ CLOCK INPUT 1.5V 1.5V tOD tH DATA OUTPUT 2.0V DATA N - 1 DATA N 0.8V FIGURE 2. INPUT-TO-OUTPUT TIMING 5 B1, N + 4 B1, N + 5 B2, N + 4 B3, N + 3 B3, N + 4 B4, N + 3 DN + 2 DN + 3 HI5805 Typical Performance Curves 11 70 fS = 5MSPS fS = 5MSPS 10 TEMPERATURE = 25oC TEMPERATURE = 25oC 60 SINAD (dB) ENOB 9 8 50 7 40 6 30 5 10 INPUT FREQUENCY (MHz) 1 100 FIGURE 4. SIGNAL TO NOISE AND DISTORTION (SINAD) vs INPUT FREQUENCY 70 -40 fS = 5MSPS fS = 5MSPS TEMPERATURE = 25oC TEMPERATURE = 25oC -50 THD (dBc) SNR (dB) 60 50 40 -60 -70 10 1 -80 100 10 1 INPUT FREQUENCY (MHz) 100 INPUT FREQUENCY (MHz) FIGURE 5. SIGNAL TO NOISE RATIO (SNR) vs INPUT FREQUENCY FIGURE 6. TOTAL HARMONIC DISTORTION (THD) vs INPUT FREQUENCY 80 11 fS = 5MSPS 2MHz 1MHz TEMPERATURE = 25oC 10 5MHz 70 9 ENOB SFDR (dBc) 100 INPUT FREQUENCY (MHz) FIGURE 3. EFFECTIVE NUMBER OF BITS (ENOB) vs INPUT FREQUENCY 30 10 1 60 8 7 50 10MHz fS = 5MSPS TEMPERATURE = 25oC 20MHz 50MHz 6 100MHz 40 10 1 100 INPUT FREQUENCY (MHz) FIGURE 7. SPURIOUS FREE DYNAMIC RANGE (SFDR) vs INPUT FREQUENCY 6 5 0.4 0.5 DUTY CYCLE (tCLK-LOW /tCLK) 0.6 FIGURE 8. EFFECTIVE NUMBER OF BITS (ENOB) vs CLOCK DUTY CYCLE AND INPUT FREQUENCY HI5805 Typical Performance Curves (Continued) 3.525 11 2MHz 1MHz 10 9 VREFNOM 10MHz VROUT (V) ENOB 3.515 5MHz 20MHz 8 fS = 5MSPS 7 3.505 3.495 VREFLD 50MHz 3.485 6 100MHz 5 -40 -20 0 20 40 TEMPERATURE (oC) 60 80 FIGURE 9. EFFECTIVE NUMBER OF BITS (ENOB) vs TEMPERATURE AND INPUT FREQUENCY 3.475 -40 -20 0 20 40 TEMPERATURE (oC) 60 80 FIGURE 10. INTERNAL VOLTAGE REFERENCE OUTPUT (VROUT) vs TEMPERATURE AND LOAD 306 70 CURRENT (mA) 304 fS = 5MSPS VIN+ = VIN- = VDC 302 300 50 40 AICC fS = 5MSPS VIN+ = VIN- = VDC 30 20 DICC1 298 10 DICC2 296 -40 -20 0 20 40 TEMPERATURE (oC) 60 FIGURE 11. POWER DISSIPATION vs TEMPERATURE 0 0 -40 80 -20 0 20 40 TEMPERATURE (oC) fIN = 1MHz, fS = 5MSPS -40 -60 -80 -100 -120 200 400 600 FREQUENCY BIN 800 FIGURE 13. 2048 POINT FFT SPECTRAL PLOT 7 60 80 FIGURE 12. POWER SUPPLY CURRENT vs TEMPERATURE -20 OUTPUT LEVEL (dB) POWER DISSIPATION (mW) ITOT 60 1000 HI5805 Pin Descriptions PIN NO. NAME 1 CLK DESCRIPTION Input Clock. 2 DVCC1 Digital Supply (5.0V). 3 DGND1 Digital Ground. 4 DVCC1 Digital Supply (5.0V). 5 DGND1 Digital Ground 6 AVCC Analog Supply (5.0V). 7 AGND Analog Ground. 8 VIN+ Positive Analog Input. 9 VIN- Negative Analog Input. 10 VDC DC Bias Voltage Output. 11 VROUT Reference Voltage Output. 12 VRIN Reference Voltage Input. 13 AGND Analog Ground. 14 AVCC Analog Supply (5.0V). 15 D11 Data Bit 11 Output (MSB). 16 D10 Data Bit 10 Output. 17 D9 Data Bit 9 Output. 18 D8 Data Bit 8 Output. 19 D7 Data Bit 7 Output. 20 D6 21 DGND2 Digital Output Ground. 22 DVCC2 Digital Output Supply (3.0V to 5.0V). 23 D5 Data Bit 5 Output. 24 D4 Data Bit 4 Output. 25 D3 Data Bit 3 Output. 26 D2 Data Bit 2 Output. 27 D1 Data Bit 1 Output. 28 D0 Data Bit 0 Output (LSB). Data Bit 6 Output. Detailed Description Theory of Operation The HI5805 is a 12-bit, fully-differential, sampling pipeline A/D converter with digital error correction. Figure 14 depicts the circuit for the front end differential-in-differential-out sampleand-hold (S/H). The switches are controlled by an internal clock which is a non-overlapping two phase signal, f1 and f2 , derived from the master clock. During the sampling phase, f1 , 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 f1 the input signal is sampled on the bottom plates of the sampling capacitors. In the next clock phase, f2 , 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 output is a fully-differential, sampled-data representation of the analog input. The circuit not only performs the sample-and-hold function but will also convert a single-ended input to a fully-differential output for the converter core. During the sampling phase, the VIN pins 8 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 100MHz for the converter. 1 VIN + 1 1 1 CS VOUT + -+ +- 2 VIN - CH VOUT - CS 1 CH 1 FIGURE 14. ANALOG INPUT SAMPLE-AND-HOLD As illustrated in the functional block diagram and the timing diagram in Figure 1, three identical pipeline subconverter stages, each containing a four-bit flash converter, a four-bit digital-to-analog converter and an amplifier with a voltage gain of 8, follow the S/H circuit with the fourth stage being only a 4-bit flash converter. Each converter stage in the pipeline will be sampling in one phase and amplifying in the other clock phase. Each individual sub-converter clock signal is offset by 180 degrees from the previous stage clock signal, with the result that alternate stages in the pipeline will perform the same operation. The 4-bit digital output of each stage is fed to a digital delay line controlled by the internal clock. The purpose of the delay line is to align the digital output data to the corresponding sampled analog input signal. This delayed data is fed to the digital error correction circuit which corrects the error in the output data with the information contained in the redundant bits to form the final 12-bit output for the converter. Because of the pipeline nature of this converter, the data on the bus is output at the 3rd cycle of the clock after the analog sample is taken. This delay is specified as the data latency. After the data latency time, the data representing each succeeding sample is output at the following clock pulse. The output data is synchronized to the external clock by a latch. The digital outputs are in offset binary format (See Table 1). Internal Reference Generator, VROUT and VRIN The HI5805 has an internal reference generator, therefore, no external reference voltage is required. VROUT must be connected to VRIN when using the internal reference voltage. The HI5805 can be used with an external reference. The converter requires only one external reference voltage connected to the VRIN pin with VROUT left open. The HI5805 is tested with VRIN equal to 3.5V. Internal to the converter, two reference voltages of 1.3V and 3.3V are generated for a fully differential input signal range of 2V. In order to minimize overall converter noise, it is recommended that adequate high frequency decoupling be provided at the reference voltage input pin, VRIN . HI5805 TABLE 1. CODE CENTER DESCRIPTION DIFFERENTIAL INPUT VOLTAGE† (USING INTERNAL REFERENCE) OFFSET BINARY OUTPUT CODE MSB LSB D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 +1.99976V 1 1 1 1 1 1 1 1 1 1 1 1 +FS - 11/4 LSB 1.99878V 1 1 1 1 1 1 1 1 1 1 1 0 + 3/4 LSB 732.4V 1 0 0 0 0 0 0 0 0 0 0 0 - 1/4 LSB -244.1V 0 1 1 1 1 1 1 1 1 1 1 1 -FS + 13/4 LSB -1.99829V 0 0 0 0 0 0 0 0 0 0 0 1 -Full Scale (-FS) + 3/4 LSB -1.99927V 0 0 0 0 0 0 0 0 0 0 0 0 +Full Scale (+FS) - 1/4 LSB † The voltages listed above represent the ideal center of each offset binary output code shown. Analog Input, Differential Connection The analog input to the HI5805 can be configured in various ways depending on the signal source and the required level of performance. A fully differential connection (Figure 15) will give the best performance for the converter. VIN+ VIN HI5805 scale, all 1s digital data output code, when the VIN+ input is at VDC +1V and the VIN- input is at VDC -1V (VIN+ - VIN- = 2V). Conversely, the ADC will be at negative full scale, all 0s digital data output code, when the VIN+ input is equal to VDC - 1V and VIN- is at VDC + 1V (VIN+ - VIN- = -2V). From this, the converter is seen to have a peak-to-peak differential analog input voltage range of 2V. The analog input can be DC coupled (Figure 16) as long as the inputs are within the analog input common mode voltage range (1.0V VDC 4.0V). VDC VIN -VIN VIN- VIN+ VDC R FIGURE 15. AC COUPLED DIFFERENTIAL INPUT Since the HI5805 is powered off a single +5V supply, the analog input must be biased so it lies within the analog input common mode voltage range of 1.0V to 4.0V. The performance of the ADC does not change significantly with the value of the analog input common mode voltage. A 2.3V DC bias voltage source, VDC , half way between the top and bottom internal reference voltages, is made available to the user to help simplify circuit design when using a differential input. This low output impedance voltage source is not designed to be a reference but makes an excellent bias source and stays within the analog input common mode voltage range over temperature. The difference between the converter’s two internal voltage references is 2V. For the AC coupled differential input, (Figure 15), if VIN is a 2VP-P sinewave with -VIN being 180 degrees out of phase with VIN , then VIN+ is a 2VP-P sinewave riding on a DC bias voltage equal to VDC and VIN- is a 2VP-P sinewave riding on a DC bias voltage equal to VDC . Consequently, the converter will be at positive full 9 C HI5805 VDC -VIN VDC R VIN- FIGURE 16. DC COUPLED DIFFERENTIAL INPUT The resistors, R, in Figure 16 are not absolutely necessary but may be used as load setting resistors. A capacitor, C, connected from VIN+ to VIN- 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. Analog Input, Single-Ended Connection The configuration shown in Figure 17 may be used with a single ended AC coupled input. Sufficient headroom must be provided such that the input voltage never goes above +5V or below AGND . HI5805 VIN+ VIN HI5805 VDC VIN- FIGURE 17. AC COUPLED SINGLE ENDED INPUT Again, the difference between the two internal voltage references is 2V. If VIN is a 4VP-P sinewave, then VIN+ is a 4VP-P sinewave riding on a positive voltage equal to VDC. The converter will be at positive full scale when VIN+ is at VDC + 2V (VIN+ - VIN- = 2V) and will be at negative full scale when VIN+ is equal to VDC - 2V (VIN+ - VIN- = -2V). In this case, VDC could range between 2V and 3V without a significant change in ADC performance. The simplest way to produce VDC is to use the VDC bias voltage output of the HI5805. The single ended analog input can be DC coupled (Figure 18) as long as the input is within the analog input common mode voltage range. VIN VIN+ VDC R HI5805 C VDC VIN - The digital CMOS outputs have a separate digital supply. This allows the digital outputs to operate from a 3.0V to 5.0V supply. When driving CMOS logic, the digital outputs will swing to the rails. When driving standard TTL loads, the digital outputs will meet standard TTL level requirements even with a 3.0V supply. In order to ensure rated performance of the HI5805, the duty cycle of the clock should be held at 50% 5%. It must also have low jitter and operate at standard TTL levels. Performance of the HI5805 will only be guaranteed at conversion rates above 0.5MSPS. This ensures proper performance of the internal dynamic circuits. Supply and Ground Considerations The HI5805 has separate analog and digital supply and ground pins to keep digital noise out of the analog signal path. 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 HI5805 should be driven by clean, linear regulated supplies. The board should also have good high frequency decoupling capacitors mounted as close as possible to the converter. If the part is powered off a single supply then the analog supply and ground pins should be isolated by ferrite beads from the digital supply and ground pins. Refer to the Application Note AN9214, “Using Intersil High Speed A/D Converters” for additional considerations when using high speed converters. Static Performance Definitions Offset Error (VOS) FIGURE 18. DC COUPLED SINGLE ENDED INPUT The resistor, R, in Figure 18 is not absolutely necessary but may be used as a load setting resistor. A capacitor, C, connected from VIN+ to VIN- 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 will give better overall system performance if it is first converted to differential before driving the HI5805. Digital I/O and Clock Requirements The HI5805 provides a standard high-speed interface to external TTL/CMOS logic families. The digital CMOS clock input has TTL level thresholds. The low input bias current allows the HI5805 to be driven by CMOS logic. 10 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 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 1 LSB. 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 Rejection Ratio (PSRR) Each of the power supplies are moved plus and minus 5% and the shift in the offset and gain error (in LSBs) is noted. HI5805 Dynamic Performance Definitions Total Harmonic Distortion (THD) Fast Fourier Transform (FFT) techniques are used to evaluate the dynamic performance of the HI5805. 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 -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. THD is the ratio of the RMS sum of the first 5 harmonic components to the RMS value of the fundamental input signal. Signal-to-Noise Ratio (SNR) SNR is 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 except the fundamental and the first five harmonics. Signal-to-Noise + Distortion Ratio (SINAD) SINAD is the measured RMS signal to RMS sum of all other spectral components below the Nyquist frequency, fS/2, excluding DC. Effective Number Of Bits (ENOB) The effective number of bits (ENOB) is calculated from the SINAD data by: ENOB = SINAD + V CORR -1.76 /6.02, where: VCORR = 0.5dB. VCORR adjusts the ENOB for the amount the input is below fullscale. 11 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 spur or 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. HI5805 Transient Response Aperture Delay (tAP) 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 12-bit accuracy. 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. Over-Voltage Recovery Aperture Jitter (tAJ) 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 12-bit accuracy. Aperture Jitter is the RMS variation in the aperture delay due to variation of internal clock path delays. 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 sinewave. The input sinewave has an amplitude which swings from -fS to +fS . The bandwidth given is measured at the specified sampling frequency. Timing Definitions Refer to Figure 1, Internal Circuit Timing, and Figure 2, Input-To-Output Timing, for these definitions. Data Hold Time (tH) Data hold time is the time to where the previous data (N - 1) is no longer valid. Data Output Delay Time (tOD) Data output delay time is the time to where the new data (N) is valid. Data Latency (tLAT) After the analog sample is taken, the digital data is output on the bus at the third cycle of the clock. This is due to the pipeline nature of the converter where the data has to ripple through the stages. This delay is specified as the data latency. After the data latency time, the data representing each succeeding sample is output at the following clock pulse. The digital data lags the analog input sample by 3 clock cycles. All Intersil semiconductor products are manufactured, assembled and tested under ISO9001 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 12