AD9066ARS-REEL

a FEATURES Two Matched ADCs on Single Chip CMOS-Compatible I/O Low-Power (400 mW) Dissipation Single +5 V Supply On-Chip Voltage Reference Self-Biased for AC-Coupled Inputs 28-Lead SOIC and SSOP Packages APPLICATIONS Direct Broadcast Satellite (DBS) Receivers QAM Demodulators Wireless LANs VSAT Receivers PRODUCT DESCRIPTION The AD9066 is a dual 6-bit ADC that has been optimized for low-cost in-phase and quadrature (I and Q) demodulators. Primary applications include digital direct broadcast satellite applications where broadband quadrature phase shift keying (QPSK) modulation is used. In these receivers the recovered signal is separated into I and Q vector components and digitized. To reduce total system cost and power dissipation, the AD9066 provides an internal voltage reference and operates from a single +5 volt power supply. Digital outputs are CMOS compatible and rated to 60 MSPS conversion rates. The digital input (ENCODE) utilizes a CMOS input stage with a TTL compatible (1.4 V) threshold. The AD9066 is housed in a 28-lead SOIC and a 28-lead SSOP package and is available in two temperature grades. The AD9066JR is rated for operation over the 0°C to 70°C commercial temperature range. The AD9066AR/ARS is rated for the –40°C to +85°C industrial temperature range. The internal voltage reference insures that the analog input is biased to midscale with low offset when driven from an accoupled source. In dc-coupled applications, the midscale voltage reference can be used to control external biasing amplifiers to minimize offsets due to variations in temperature or supply voltage. Dual 6-Bit, 60 MSPS Monolithic A/D Converter AD9066 FUNCTIONAL BLOCK DIAGRAM +VS AD9066 VT INA 6-BIT DAC D0A-D5A 6-BIT DAC D0B-D5B REF A ENCODE INB REF B VB PIN CONFIGURATIONS ENCODE 1 28 D5A (MSB) +VS 2 27 D4A GND 3 26 D3A GND 4 25 D2A +VS 5 INA 6 24 D1A AD9066 (JR/AR) 23 D0A (LSB) GND 7 TOP VIEW 22 GND +VS 8 (Not to Scale) 21 +VS VT 9 20 D5B (MSB) REF A 10 19 D4B INB 11 18 D3B REF B 12 17 D2B VB 13 16 D1B NC 14 15 D0B (LSB) NC = NO CONNECT +VS 1 28 GND VT 2 27 INA REF A 3 26 +VS INB 4 25 GND 24 GND REF B 5 AD9066 +VS (ARS) TOP VIEW 22 ENCODE (LSB) D0B 8 (Not to Scale) 21 D5A (MSB) VB 6 23 NC 7 REV. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices 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 Analog Devices. D1B 9 20 D4A D2B 10 19 D3A D3B 11 18 D2A D4B 12 17 D1A (MSB) D5B 13 16 D0A (LSB) +VS 14 15 GND NC = NO CONNECT One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 2000 AD9066–SPECIFICATIONS ELECTRICAL CHARACTERISTICS (+V = +5 V, AIN = 15.5 MHz, Encode Rate = 60 MSPS, T S Parameter Test Level Temp Min ANALOG INPUT Full-Scale Input Range Gain Matching (FS Range) DC Input (Midscale)1 Input Offset1 Input Capacitance Input Resistance (DC) Input Bandwidth (3 dB) Gain Flatness (to 15 MHz) Integral Linearity Differential Linearity Monotonicity VI IV V VI IV VI V V VI VI VI Full Full +25°C Full Full Full +25°C +25°C Full Full Full 475 SWITCHING PERFORMANCE Max Conversion Rate Output Delay (tV)2 Output Delay (tPD)2 Aperture Uncertainty (Jitter) Aperture Time (tA) VI IV IV V V Full Full Full +25°C +25°C 60 4 DYNAMIC PERFORMANCE3 Effective Number of Bits SINAD Harmonic Distortion (THD) Crosstalk Rejection VI VI VI IV +25°C +25°C +25°C +25°C 5.3 34 40 40 ENCODE INPUT Logic High Voltage Logic Low Voltage Input High Current Input Low Current Pulsewidth High Pulsewidth Low VI VI VI VI IV IV Full Full Full Full Full Full 2.0 DIGITAL OUTPUTS Output Coding Logic High Voltage (IOH = 1 mA) Logic Low Voltage (IOL = 1 mA) VI VI Full Full Full POWER SUPPLY +VS Supply Voltage Power Supply Rejection Ratio1 +VS Supply Current Power Dissipation4 VI IV VI VI Full Full Full Full AD9066JR Typ 500 Max Min 525 16 450 +1.0 15 55 –1.0 +1.0 +0.5 –1.0 –0.5 +VS – 1.1 –1.0 25 10 45 100 0.25 –1.0 –0.5 C = T A) AD9066AR/ARS Typ Max 500 530 16 +VS – 1.1 22 Guaranteed 10 45 100 0.25 +1.0 15 57 +1.0 +0.5 10 1.0 MSPS ns ns ps rms ns 5.7 36 50 50 Bits dB dB dBc 11 12 10 1.0 5.7 36 50 50 5.2 33 40 40 2.0 0.8 500 500 7.0 7.0 0.8 500 500 7.0 7.0 Offset Binary V V µA µA ns ns Offset Binary 3.8 3.8 0.4 110 80 400 mV mV V LSBs pF kΩ MHz dB LSBs LSBs Guaranteed 60 4 4.75 Unit 5.25 130 120 600 4.75 110 80 400 0.4 V V 5.25 130 120 600 V mV/V mA mW NOTES 1 For ac coupled applications, the ADC is internally biased to insure that the midpoint transition of the ADC is within the limits specified with no signal applied. For dc coupled applications, the dc value of the midpoint transition voltage will track the supply voltage within the limits shown for dc input (midscale) plus the dc offset. Power Supply Rejection Ratio (PSRR) refers to the variation of the input signal range (gain) to supply voltage. 2 tV and tPD are measured from the 1.4 V level of the Clock and the 50% level between VOH and VOL. The ac load on all the digital outputs during test is 10 pF (max), the dc load will not exceed ± 40 µA. 3 Effective number of bits (ENOB) and THD are measured using a FFT with a pure sine wave analog input @ 15.5 MHz, 1 dB below full scale. ENOB is calculated by ENOB = (SNR – 1.76 dB)/6.02; THD is measured from full scale to the sum of the second through seventh harmonic of the input. 4 Typical thermal impedance for the “R” style (SOIC) 28-lead package is: θJC = 4°C/W, θCA = 41°C/W, θJA = 45°C/W, and the “RS” style (SSOP) 28-lead package is: θJC = 26.97°C/W, θCA = 51.61°C/W, θJA = 78.58°C/W. Specifications subject to change without notice. –2– REV. A AD9066 PIN DESCRIPTIONS ABSOLUTE MAXIMUM RATINGS Pin Min Max Unit ENCODE +VS INA, INB VT REF A, REF B VB D0–D5 Current OUT –0.5 +VS 7.0 +VS +VS +VS +VS 20 V V V V V V mA –0.5 2.5 –0.5 0.0 AR:JR ARS Pin Pin No. No. Name EXPLANATION OF TEST LEVELS Test Level Description I II 100% Production Tested 100% Production Tested at +25°C, and Sample Tested at Specified Temperatures Sample Tested Only Parameter Is Guaranteed by Design Parameter Is Typical Value Only 100% Tested at +25°C III IV V VI DIE LAYOUT AND MECHANICAL INFORMATION Die Dimensions . . . . . . . . . . . . . . . . . 132 × 68 × 21 (± 1) mils Pad Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 × 4 mils Metalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aluminum Backing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . None Substrate Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . Ground Transistor Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5,810 Passivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . Silicon Nitride Die Attach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Silver Filled Bond Wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gold ORDERING GUIDE Model Temperature Range Package Option* AD9066AR AD9066JR AD9066ARS –40°C to +85°C 0°C to +70°C –40°C to +85°C R-28 R-28 RS-28 *R = “SO” Small Outline Package; RS = SSOP. 1 22 ENCODE 2 3 4 5 6 7 8 9 23 24 25 26 27 28 1 2 +VS GND GND +VS INA GND +VS VT 10 3 REF A 11 12 4 5 INB REF B 13 6 VB 14 15 7 8 NC D0B (LSB) 16 17 18 19 20 21 22 23 9 10 11 12 13 14 15 16 24 25 26 27 28 17 18 19 20 21 D1B D2B D3B D4B D5B (MSB) +VS +5 V Supply for Digital Outputs. GND Ground. D0A (LSB) Digital Outputs Channel A, CMOS Compatible. D1A D2A D3A D4A D5A (MSB) CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD9066 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. REV. A –3– Function TTL Compatible CMOS Clock, Samples on Rising Edge. +5 V Supply for Digital Input. Ground. Ground. +5 V Supply (Analog). Channel A Analog Input. Ground. +5 V Supply (Analog). Top of Voltage Reference, Bypass to GND. Mid Reference to ADC A, Bypass to GND. Channel B Analog Input. Mid Reference to ADC B, Bypass to GND. Bottom of Reference Ladder, Bypass to GND. No Connect. Digital Outputs Channel B, CMOS Compatible. WARNING! ESD SENSITIVE DEVICE AD9066 Gain Variation 5.8 The full-scale input range is established by the current through the two matched resistor ladders (620 ohms each nominal). Therefore the gain of the ADC may be modified by forcing different voltages across the top and bottom voltage taps (VT and VB). ENCODE = 60MSPS 5.7 ENOB – Bits 5.6 The easiest way to increase the input range will be to force VB to a lower voltage. Using an external amplifier, the voltage at VB may be forced as low as 3.0 V (3.58 nominal). Using the previously described relationship for full scale and the internal resistor ladder values, 3.0 V at VB will result in a nominal fullscale input range of 705 mV. 5.5 5.4 5.3 A larger input range can be established by taking the VT voltage all the way to the supply voltage level while pulling VB to 3.0 V. This would force a 2 V potential across the ladder and create a full-scale input range of 1.6 V. 5.2 1 10 MHz 100 Figure 1. ENOB vs. Analog Input Frequency Greater flexibility and improved power supply rejection can be achieved by forcing external voltage references at both the top and bottom of the resistor ladder. 5.8 ANALOG INPUT = 10.1MHz 111111 5.7 2n –2 = 62 ENOB – Bits 5.6 100000 5.5 011111 5.4 5.3 000001 000000 5.2 10 100 –FULL-SCALE MHz MIDSCALE +FULL-SCALE Figure 3. Figure 2. ENOB vs. Encode Rate USING THE AD9066 Analog Input and Voltage References +VS = 5V 400⍀ The AD9066 is optimized to allow ac coupled inputs with a fullscale input range of 500 mV ± 5%. An LSB weight is approximately 8 mV. The full-scale input range is defined as the voltage range that accommodates 2n – 2 codes of equally weighted LSBs (between the first and last code transitions). For the AD9066 there are 32 codes above and below the midscale voltage of the A see Figure 3). VS VT 40k⍀ 310⍀ 310⍀ 40k⍀ REF B REF A INPUT 310⍀ 310⍀ VB 2mA The full-scale input range of the AD9066 is equal to 500/620 × (VT – VB), or nominally 500 mV. For dc coupled applications, the REF A and REF B voltages can be used to feed back offset compensation signals. This will allow the midscale transition voltage of the ADCs to track supply and temperature variations. a. Reference Circuit 1.4V THRESHOLD b. Encode Input VS VS In the event that offset correction signals are generated digitally, the REF pins would not be required. Figure 4a shows the equivalent circuit for the internal references. All component tolerances are ± 25%. OUTPUTS 40k⍀ REF c. Output Bits d. Analog Input Figure 4. Equivalent Circuits –4– REV. A AD9066 Timing ENCODE 866⍀ The duty cycle of the encode clock for the AD9066 is critical in obtaining rated performance of the ADC. Rated maximum and minimum pulse widths should be maintained, especially for sample rates greater than 40 MSPS. 6 BITS 866⍀ The AD9066 provides latched data outputs with three pipeline delays. The length and load on the output data lines should be minimized to reduce power supply transients inside the AD9066 which might diminish dynamic performance. 2k⍀ 866⍀ N 6 BITS tA N+1 +15V 866⍀ INB 1/2 AD812 + ENCODE –15V tV VALID DATA FOR N–3 tPD VALID DATA FOR N–2 Figure 6. Bipolar Input Using AD812 Drive for AD9066 VALID DATA FOR N–1 Layout should follow high frequency/high speed design guidelines. In addition the capacitance around the inverting input to the AD812 should be minimized through a tight layout and the use of low capacitance chip resistors for gain setting. DATA CHANGING Figure 5. Timing Diagram Quadrature Receiver Using the AD9066 The data is invalid during the period between tV and tPD. This period refers to the time required for the AD9066 to fully switch between valid CMOS logic levels. When latching the output data, be careful to observe latch setup and hold time restrictions as well as this data invalid period when designing the system timing. Although any type of input signal may be applied, the AD9066 has been optimized for low cost in-phase and quadrature (I and Q) demodulators. Primary applications include digital direct broadcast satellite applications where broadband quadrature phase shift keying (QPSK) modulation is used. In these receivers the recovered signal is separated into I and Q vector components and digitized. Layout and Signal Care To insure optimum performance, a single low impedance ground plane is recommended. Analog and digital grounds should be connected together at the AD9066. Analog and digital power supplies should be bypassed, at the device, to ground through 0.1 µF ceramic capacitors. AD9066 IF IN Driving the AD9066 with a Bipolar Input VCO The analog input range of the AD9066 is between 3.7 V and 4.2 V. Because the input is offset, the normal method of driving the analog input is to use a blocking capacitor between the analog source and the AD9066 analog input pins. In applications where DC coupling must be employed, the simple circuit shown in Figure 6 will take a bipolar input and offset it to the operating range of the AD9066. LPF ADC LPF ADC 90ⴗ The use of sockets may limit the dynamic performance of the part and is not recommended except for prototype or evaluation purposes. VCO Figure 7. Simplified Block Diagram For data symbol rates less than 10 Mbaud, the AD607 IF/RF receiver subsystem provides an ideal solution for the second conversion stage of a complete receiver system. Figure 8 shows the AD9066 and AD607 used together. The AD607 accepts inputs as high as 500 MHz which may be the output of the first IF stage or RF signals directly. The IF/RF signal is mixed with the local oscillator to provide an IF frequency of 400 kHz to 22 MHz. This signal is filtered externally and then amplified with an on-chip AGC before being synchronously demodulated with an on-chip PLL carrier recovery circuit. The outputs are digitized with the AD9066. The digital outputs may be processed with a DSP chip such as the ADSP2171, ADSP-21062, general purpose DSP or ASIC. To offset the input, the midpoint voltage of the AD9066 is buffered off chip and then inverted with an AD712, a low input bias current dual op amp. This inverted midpoint is then fed to a summation amplifier that combines the bipolar input with the inverted offset voltage. The summation amplifier is an AD812, a wideband current feedback amplifier that provides good bandwidth and low distortion. REV. A REF A OR REF B + 1/2 AD712 N+2 D0–D5 AD9066 1/2 AD712 2k⍀ 866⍀ 866⍀ ANALOG INPUT 1/2 AD812 + + INA –5– AD9066 CLOCK LOCAL OSCILLATOR 1 CLKIN –16dBM 6 10⍀ VMID VINA 0ⴗ + BANDPASS FILTER RF INPUT (ANTENNA) + OPTIONAL BPF OR LPF 330⍀ 330⍀ 100nF 10⍀ 4.7␮F MIDPOINT BIAS GENERATOR 90ⴗ VINB 20 19 18 17 16 15 B OUTPUTS (QUADRATURE) AGC DETECTOR AGC VOLTAGE AD607 A OUTPUTS (INPHASE) AD9066 PLL 11 100nF 28 27 26 25 24 23 BIAS CIRCUIT RECEIVED SIGNAL STRENGTH INDICATOR PTAT VOLTAGE Figure 8. Digitizer with AD607 Receiver Circuit The outputs of the comparators are converted to a 6-bit word and converted to CMOS levels. The digital signals are latched at six stages (two pipeline delays) in the signal path. The digital outputs are CMOS with approximately equal rise and fall times. Theory of Operation The AD9066 dual ADC employs a patented interpolated flash architecture. This architecture enables 64 possible quantization levels with only 32 comparator preamplifiers. This keeps input capacitance to a minimum. The midpoint of the reference ladder is fed back to the analog input, allowing easy biasing of the ADC to midscale for ac coupled applications. The encode clock utilizes a CMOS input stage with TTLcompatible (1.4 V) thresholds. Internal clock buffers minimize external clock drive requirements. As shown in Figure 4d, a simple resistor is used to provide the reference ladder midpoint to the analog input. The high impedance MOS inputs of the comparators insure no static voltage drop across the resistor. This eliminates the need for an active buffer (and its inherent offsets) to set the reference midpoint at the analog input. –6– REV. A AD9066 OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 0.7125 (18.10) 0.6969 (17.70) 28 15 0.2992 (7.60) 0.2914 (7.40) 1 0.4193 (10.65) 0.3937 (10.00) 14 PIN 1 0.1043 (2.65) 0.0926 (2.35) 0.0118 (0.30) 0.0040 (0.10) 0.0500 (1.27) BSC 8ⴗ 0ⴗ 0.0192 (0.49) SEATING 0.0125 (0.32) PLANE 0.0138 (0.35) 0.0091 (0.23) 0.0291 (0.74) ⴛ 45ⴗ 0.0098 (0.25) C2019–0–6/00 (rev. A) 00566 28-Lead Small Outline Package (R-28) 0.0500 (1.27) 0.0157 (0.40) 28-Lead SSOP (RS-28) 0.407 (10.34) 0.397 (10.08) 15 1 14 0.311 (7.9) 0.301 (7.64) 0.212 (5.38) 0.205 (5.21) 28 0.078 (1.98) PIN 1 0.068 (1.73) 8° 0.015 (0.38) 0° SEATING 0.009 (0.229) 0.010 (0.25) PLANE 0.005 (0.127) 0.03 (0.762) 0.022 (0.558) PRINTED IN U.S.A. 0.008 (0.203) 0.0256 (0.65) 0.002 (0.050) BSC 0.07 (1.79) 0.066 (1.67) REV. A –7–