HI1175
August 1997
8-Bit, 20 MSPS, Flash A/D Converter
Description
The HI1175 is an 8-bit, analog-to-digital converter built in a 1.4µm CMOS process. The low power, low differential gain and phase, high sampling rate, and single 5V supply make the HI1175 ideal for video and imaging applications. The adoption of a 2-step flash architecture achieves low power consumption (60mW) at a maximum conversion speed of 20 MSPS (Min), 35 MSPS typical with only a 2.5 clock cycle data latency. The HI1175 also features digital output enable/disable and a built in voltage reference. The HI1175 can be configured to use the internal reference or an external reference if higher precision is required.
Features
• Resolution . . . . . . . . . . . . . . . . . . 8-Bit ±0.3 LSB (DNL) • Maximum Sampling Frequency . . . . . . . . . . . 20 MSPS • Low Power Consumption . . . .60mW (at 20 MSPS Typ) (Reference Current Excluded) • Built-In Sample and Hold Circuit • Built-In Reference Voltage Self Bias Circuit • Three-State TTL Compatible Output • Single +5V Power Supply • Low Input Capacitance . . . . . . . . . . . . . . . . . 11pF (Typ) • Reference Impedance . . . . . . . . . . . . . . . . . . 300Ω (Typ) • Evaluation Board Available (HI1175-EV) • Low Cost • Direct Replacement for the Sony CXD1175
Ordering Information
PART NUMBER HI1175JCP HI1175JCB HI1175-EV TEMP. RANGE (oC) -40 to 85 -40 to 85 25 PACKAGE 24 Ld PDIP 24 Ld SOIC Evaluation Board PKG. NO. E24.4-S M24.2-S
Applications
• Video Digitizing • Image Scanners • Multimedia • PC Video Capture • TV Set Top Boxes • Personal Communication Systems (PCS)
Pinout
HI1175 (PDIP, SOIC) TOP VIEW
OE DVSS D0 (LSB) D1 D2 D3 D4 D5 D6 D7 (MSB) DVDD CLK
1 2 3 4 5 6 7 8 9 10 11 12
24 DVSS 23 VRB 22 VRBS 21 AVSS 20 AVSS 19 VIN 18 AVDD 17 VRT 16 VRTS 15 AVDD 14 AVDD 13 DVDD
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. http://www.intersil.com or 407-727-9207 | Copyright © Intersil Corporation 1999
File Number
3577.6
4-1069
HI1175 Functional Block Diagram
OE DVSS D0 (LSB) D1 D2 D3 D4 D5 D6 1 2 3 4 5 6 7 8 9 UPPER DATA LATCHES LOWER DATA LATCHES LOWER ENCODER (4-BIT) LOWER COMPARATORS WITH S/H (4-BIT) REFERENCE VOLTAGE 24 DVSS 23 VRB 22 VRBS 0.6V (Typ)
21 AVSS 20 AVSS
LOWER ENCODER (4-BIT)
LOWER COMPARATORS WITH S/H (4-BIT)
19 VIN 18 AVDD 17 VRT
D7 (MSB) 10 DVDD 11 CLK 12 CLOCK GENERATOR
UPPER ENCODER (4-BIT)
UPPER COMPARATORS WITH S/H (4-BIT)
16
VRTS 2.6V (Typ)
15 AVDD 14 AVDD 13 DVDD
Typical Application Schematic
HC04 CA158A R4 + +5V C9 + 4.7µF C10 0.1µF R5 + 13 14 15 CA158A C12 0.1µF C8 16 17 18 12 11 10 9 8 7 HI1175 19 20 R1 R2 21 22 23 C11 0.1µF C7 + 4.7µF +5V 24 6 5 4 3 2 1 D3 D2 D1 D0 (LSB) D7 (MSB) D6 D5 D4 CLOCK IN CLK +5V
R11 R3
R13
ICL8069
R12
-
HA2544 VIN +
†
-
†
: Ceramic Chip Capacitor 0.1µF : Analog GND : Digital GND
NOTE: It is necessary that AVDD and DVDD pins be driven from the same supply. The gain of analog input signal can be changed by adjusting the ratio of R2 to R1.
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HI1175 Pin Descriptions and Equivalent Circuits
PIN NUMBER 1 SYMBOL OE EQUIVALENT CIRCUIT
DVDD
DESCRIPTION When OE = Low, Data is valid. When OE = High, D0 to D7 pins high impedance.
1
DVSS
2, 24 3-10
DVSS D0 to D7
Digital GND. D0 (LSB) to D7 (MSB) Output.
D1
11, 13 12
DVDD CLK
DVDD
Digital +5V. Clock Input.
12
DVSS
16
VRTS
AVDD
Shorted with VRT generates, +2.6V.
16
17 23
VRT VRB
17
AVDD
Reference Voltage (Top). Reference Voltage (Bottom).
23
AVSS
14, 15, 18 19
AVDD VIN
AVDD
Analog +5V. Analog Input.
19
AVSS
20, 21 22
AVSS VRBS
AVSS
Analog GND. Shorted with VRB generates +0.6V.
22
4-1071
HI1175
Absolute Maximum Ratings
Supply Voltage, VDD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V Reference Voltage, VRT, VRB . . . . . . . . . . . . . . . . . . . . . VDD to VSS Analog Input Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . VDD to VSS Digital Input Voltage, CLK. . . . . . . . . . . . . . . . . . . . . . . . VDD to VSS Digital Output Voltage, VOH, VOL . . . . . . . . . . . . . . . . . . VDD to VSS
Thermal Information
Thermal Resistance (Typical, Note 1) θJA (oC/W) PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . 150oC Maximum Storage Temperature Range, TSTG . . . . . -65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300oC (SOIC - Lead Tips Only)
Operating Conditions
(Note 1)
Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC Supply Voltage AVDD , AVSS , DVDD , DVSS . . . . . . . . . . . . . . . +4.75V to +5.25V |DGND-AGND| . . . . . . . . . . . . . . . . . . . . . . . . . . . .0mV to 100mV Reference Input Voltage VRB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V and Above VRT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8V and Below Analog Input Range, VIN . . . . . . . VRB to VRT (1.8VP-P to 2.8VP-P) Clock Pulse Width tPW1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25ns (Min) tPW0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25ns (Min)
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
PARAMETER SYSTEM PERFORMANCE Offset Voltage EOT EOB Integral Non-Linearity, INL Differential Non-Linearity, DNL DYNAMIC CHARACTERISTICS Effective Number of Bits, ENOB Spurious Free Dynamic Range Signal to Noise Ratio, SINAD RMS Signal = ----------------------------------------------------------------RMS Noise + Distor tion Maximum Conversion Speed, fC Minimum Conversion Speed Differential Gain Error, DG Differential Phase Error, DP Aperture Jitter, tAJ Sampling Delay, tDS Data Latency, tLAT ANALOG INPUTS
fC = 20 MSPS, VDD = +5V, VRB = 0.5V, VRT = 2.5V, TA = 25oC (Note 1) TEST CONDITIONS MIN TYP MAX UNIT
-60 0 fC = 20 MSPS, VIN = 0.6V to 2.6V fC = 20 MSPS, VIN = 0.6V to 2.6V -
-35 +15 ±0.5 ±0.3
-10 +45 ±1.3 ±0.5
mV mV LSB LSB
fIN = 1MHz fIN = 1MHz fC = 20MHz, fIN = 1MHz fC = 20MHz, fIN = 3.58MHz VIN = 0.6V to 2.6V, fIN = 1kHz Ramp
20 -
7.6 51 46 46 35 1.0 0.5 30 4 -
0.5 2.5
Bits dB dB dB MSPS MSPS % Degree ps ns Cycles
NTSC 40 IRE Mod Ramp, fC = 14.3 MSPS
-
Analog Input Bandwidth (-1dB), BW Analog Input Capacitance, CIN VIN = 1.5V + 0.07VRMS
-
18 11
-
MHz pF
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HI1175
Electrical Specifications
PARAMETER REFERENCE INPUT Reference Pin Current, IREF Reference Resistance (VRT to VRB), RREF INTERNAL VOLTAGE REFERENCE Self Bias Mode 1 VRB VRT - VRB Self Bias Mode 2, VRT DIGITAL INPUTS Digital Input Voltage VIH VIL Digital Input Current IIH IIL DIGITAL OUTPUTS Digital Output Current IOH IOL Digital Output Current IOZH IOZL TIMING CHARACTERISTICS Output Data Delay, tDL POWER SUPPLY CHARACTERISTIC Supply Current, IDD NOTE: 2. Electrical specifications guaranteed only under the stated operating conditions. fC = 20 MSPS, NTSC Ramp Wave Input 12 17 mA 18 30 ns OE = VDD , VDD = Max VOH = VDD VOL = 0V 0.01 0.01 16 16 µA µA OE = VSS , VDD = Min VOH = VDD -0.5V VOL = 0.4V -1.1 3.7 mA mA VDD = Max VIH = VDD VIL = 0V 5 5 µA µA 4.0 1.0 V V VRB = AGND, Short VRT and VRTS Short VRB and VRBS , Short VRT and VRTS 0.60 1.96 2.25 0.64 2.09 2.39 0.68 2.21 2.53 V V V 4.5 230 6.6 300 8.7 450 mA Ω fC = 20 MSPS, VDD = +5V, VRB = 0.5V, VRT = 2.5V, TA = 25oC (Note 1) (Continued) TEST CONDITIONS MIN TYP MAX UNIT
Timing Diagrams
tPW1 tPW0
CLOCK ANALOG INPUT
N
N+1
N-2 N-1
N+3 N
N+4 N+1
DATA OUTPUT
N-3
N-2
: POINT FOR ANALOG SIGNAL SAMPLING
tD = 18ns
FIGURE 1.
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HI1175 Timing Diagrams
VI (1) VI (2) VI (3) VI (4)
ANALOG INPUT
EXTERNAL CLOCK
UPPER COMPARATOR BLOCK
S (1)
C (1)
S (2)
C (2)
S (3)
C (3)
S (4)
C (4)
UPPER DATA
MD (0)
MD (1)
MD (2)
MD (3)
LOWER REFERENCE VOLTAGE
RV (0)
RV (1)
RV (2)
RV (3)
LOWER COMPARATOR BLOCK A
S (1)
H (1)
C (1)
S (3)
H (3)
C (3)
LOWER DATA A
LD (-1)
LD (1)
LOWER COMPARATOR BLOCK B
H (0)
C (0)
S (2)
H (2)
C (2)
S (4)
H (4)
LOWER DATA B
LD (-2)
LD (0)
LD (2)
DIGITAL OUTPUT
OUT (-2)
OUT (-1)
OUT (0)
OUT (1)
FIGURE 2.
Typical Performance Curves
20 VPP = 5.0V, VRT = 2.5V, VRB = 0.5V TA = 25oC, VIN = 2VP-P POWER DISSIPATION (mW) 20 15 IDD (mA) IDD (mA) 15 100
10
10 5
50
4.0
4.5
5.0
5.5
5
0
5
10
15
20
25
30
35
POWER SUPPLY VOLTAGE (V)
SAMPLING RATE (MSPS)
FIGURE 3. SUPPLY CURRENT vs SUPPLY VOLTAGE
FIGURE 4. SUPPLY CURRENT AND POWER vs SAMPLING RATE
4-1074
HI1175 Typical Performance Curves
1.4 DIFFERENTIAL NON-LINEARITY (LSB) TA = 25oC, VRT = 2.5V, VRB = 0.5V VDD = 5.0V, fC = 20 MSPS
(Continued)
50 49 48 ENCODE 21MHz
1.0
47 46 (dB) 45 44 43 42 ENCODE 31MHz ENCODE 26MHz
0.6
0.2 0 0 2 4 6 8 10 INPUT FREQUENCY (MHz)
41 40 0 1 2 3 4 5 6 7 8 INPUT FREQUENCY (MHz) 9 10 11
FIGURE 5. DIFFERENTIAL NON-LINEARITY vs INPUT FREQUENCY
FIGURE 6. HI1175JCP SNR vs INPUT FREQUENCY
8.00 7.75 7.50 7.25 7.00 (BITS) 6.75 6.50 6.25 6.00 5.75 5.50 5.25 5.00 0 1 2 3 4 5 6 7 8 INPUT FREQUENCY (MHz) 9 10 11 ENCODE 31MHz ENCODE 26MHz (dB) ENCODE 21MHz
-30 -33 -35 -38 -40 -43 -45 -48 -50 -53 -55 0 1 2 3 4 5 6 7 8 INPUT FREQUENCY (MHz) 9 10 11 ENCODE 21MHz ENCODE 31MHz ENCODE 26MHz
FIGURE 7. HI1175JCP ENOB vs INPUT FREQUENCY
FIGURE 8. HI1175JCP THD vs INPUT FREQUENCY
8.00 7.75 7.50 7.25 ENOB (BITS) 7.00 6.75 6.50 6.25 6.00 5.75 5.50 5.25 5.00 21 26 31 36 fIN = 10MHz INL (LSB) fIN = 5MHz fIN = 1MHz
1.0
0.8
0.6
0.4
0.2
0
-0.2 -55
-35
-15
CLOCK FREQUENCY (MHz)
5 25 45 65 TEMPERATURE (oC)
85
105
125
FIGURE 9. ENOB vs CLOCK FREQUENCY
FIGURE 10. INL vs TEMPERATURE
4-1075
HI1175 Typical Performance Curves
5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 -55 -35 -15 IOH = 1.1mA 10 -55 SUPPLY CURRENT (mA) OUTPUT VOLTAGE (V) IOH = -3.7mA 18
(Continued)
20
16
fC = 35MHz
14 fC = 20MHz 12
5 25 45 65 TEMPERATURE (oC)
85
105
125
-35
-15
5 25 45 65 TEMPERATURE (oC)
85
105
125
FIGURE 11. DIGITAL OUTPUT VOLTAGE vs TEMPERATURE
FIGURE 12. SUPPLY CURRENT vs TEMPERATURE
0.2 0.15 0.1
54 fIN = 1MHz 53
52 DNL (LSB) 0.05 0 -0.05 -0.1 -0.15 -55 49 SFDR (dB) -35 -15 5 25 45 65 TEMPERATURE (oC) 85 105 125
51
50
48 -55
-35
-15
5 25 45 65 TEMPERATURE (oC)
85
105
125
FIGURE 13. DNL vs TEMPERATURE
FIGURE 14. SFDR vs TEMPERATURE
-48 fIN = 1MHz -49
8.0 7.9 7.8 ENOB (BITS) fIN = 1MHz
-50 THD (dB)
7.7 7.6 7.5 7.4
-51
-52
-53
7.3 7.2 -55
-54 -55
-35
-15
5 25 45 65 TEMPERATURE (oC)
85
105
125
-35
-15
5 25 45 65 TEMPERATURE (oC)
85
105
125
FIGURE 15. THD vs TEMPERATURE
FIGURE 16. ENOB vs TEMPERATURE
4-1076
HI1175 Typical Performance Curves
(Continued)
2.5 VRT SHORTED TO VRTS VRB = AGND 2.45 VRT - VRB (V)
2.2 VRB SHORTED TO VRBS VRT SHORTED TO VRTS 2.15
VRT (V)
2.4
2.1
2.35
2.05
2.3 -40
-15
10
35
60
85
2.0 -40
-15
10
35
60
85
TEMPERATURE (oC)
TEMPERATURE (oC)
FIGURE 17. VRT vs TEMPERATURE
FIGURE 18. VRT - VRB vs TEMPERATURE
0.75 VRB SHORTED TO VRBS VRT SHORTED TO VRTS
25 OUTPUT RISING EDGE 20
0.7 DATA DELAY (ns) 15 OUTPUT FALLING EDGE
VRB (V)
0.65
10
0.6 5
0.55 -40
-15
10
35
60
85
0 -40
-15
10
35
60
85
TEMPERATURE (oC)
TEMPERATURE (oC)
FIGURE 19. VRB vs TEMPERATURE
FIGURE 20. OUTPUT DATA DELAY vs TEMPERATURE A/D OUTPUT CODE TABLE
INPUT SIGNAL VOLTAGE VRT • • • • • • • • VRB
DIGITAL OUTPUT CODE STEP 255 • • • 128 127 • • • 0 0 0 0 0 1 0 0 1 0 1 0 1 MSB 1 D6 1 D5 1 D4 1 D3 1 • • • 0 1 • • • 0 0 0 0 0 1 0 1 0 1 D2 1 D1 1 LSB 1
4-1077
HI1175 Detailed Description
The HI1175 is a 2-step A/D converter featuring a 4-bit upper comparator group and two lower comparator groups of 4 bits each. The reference voltage can be obtained from the onboard bias generator or be supplied externally. This IC uses an offset canceling type comparator that operates synchronously with an external clock. The operating modes of the part are input sampling (S), hold (H), and compare (C). The operation of the part is illustrated in Figure 2. A reference voltage that is between VRT -VRB is constantly applied to the upper 4-bit comparator group. VI(1) is sampled with the falling edge of the first clock by the upper comparator block. The lower block A also samples VI(1) on the same edge. The upper comparator block finalizes comparison data MD(1) with the rising edge of the first clock. Simultaneously the reference supply generates a reference voltage RV(1) that corresponds to the upper results and applies it to the lower comparator block A. The lower comparator block finalizes comparison data LD(1) with the rising edge of the second clock. MD(1) and LD(1) are combined and output as OUT(1) with the rising edge of the third clock. There is a 2.5 cycle clock delay from the analog input sampling point to the corresponding digital output data. Notice how the lower comparator blocks A and B alternate generating the lower data in order to increase the overall A/D sampling rate. Power, Grounding, and Decoupling To reduce noise effects, separate the analog and digital grounds. In order to avoid latchup at power up, it is necessary that AVDD and DVDD be driven from the same supply. Bypass both the digital and analog VDD pins to their respective grounds with a ceramic 0.1µF capacitor close to the pin. Analog Input The input capacitance is small when compared with other flash type A/D converters. However, it is necessary to drive the input with an amplifier with sufficient bandwidth and drive capability. In order to prevent parasitic oscillation, it may be necessary to insert a low value (i.e., 0.24Ω) resistor between the output of the amplifier and the A/D input. Reference Input The range of the A/D is set by the voltage between VRT and VRB . The internal bias generator will set VRTS to 2.6V and VRBS to 0.6V. These can be used as the part reference by shorting VRT and VRTS and VRB to VRBS . The analog input range of the A/D will now be from 0.6V to 2.6V and is referred to as Self Bias Mode 1. Self Bias Mode 2 is where VRB is connected to AGND and VRT is shorted to VRTS . The analog input range will now be from 0V to 2.4V.
Test Circuits
+V
S2
+ S1
S1 : ON IF A < B S2 : ON IF A > B
-V AB 8 COMPARATOR A8 TO A1 A0 B8 TO B1 B0 BUFFER
“0” DVM CLK (20MHz)
“1” 8 000 • • • 00 TO 111 • • • 10
CONTROLLER
FIGURE 21. INTEGRAL AND DIFFERENTIAL NON-LINEARITY ERROR AND OFFSET VOLTAGE TEST CIRCUIT
4-1078
HI1175 Test Circuits
fC -1kHz SG 0.6V 1 2 NTSC SIGNAL SOURCE 40 IRE MODULATION BURST 0.6V -5.2V TTL fC ECL AMP VIN DUT HI1175 8 TTL ECL 620 2.6V -5.2V 620 SYNC DG DP 8 HI20201 1 10-BIT D/A CLK 2 VECTOR SCOPE HPF COUNTER
(Continued)
2.6V ERROR RATE
100
IRE 0 -40 SG (CW)
FIGURE 22. MAXIMUM OPERATIONAL SPEED AND DIFFERENTIAL GAIN AND PHASE ERROR TEST CIRCUIT
2.6V 0.6V
VDD VRT VIN VRB HI1175 CLK OE GND VOL
2.6V IOL 0.6V
VDD VRT VIN VRB HI1175 CLK
IOH
+
OE GND
VOH
+
-
-
FIGURE 23. DIGITAL OUTPUT CURRENT TEST CIRCUIT
ICL8069 REFERENCE
AMP
A/D
DSP/µP
D/A
AMP
HA5020 (Single) HA5022(Dual) HA5024 (Quad) HA5013 (Triple)
HI1175 (8-Bit)
HSP9501 HSP48901 HSP43881 HSP43168
HI3338 (8-Bit) HI1171 (8-Bit)
HA5020 (Single)
HSP9501: Programmable Data Buffer HSP48901: 3 x 3 Image Filter, 30MHz, 8-Bit HSP43881: Digital Filter, 30MHz, 1-D and 2-D FIR Filters HSP43168: Dual FIR Filter, 10-Bit, 33MHz/45MHz CMOS Logic Available in HC, HCT, AC, ACT and FCT. HA5013: HA5020: HA5022: HA5024: Triple, 125MHz, IOUT = 20mA Single, 100MHz, IOUT = 30mA, Output Enable/Disable Dual, 125MHz, IOUT = 20mA, Output Enable/Disable Quad, 125MHz, IOUT = 20mA, Output Enable/Disable FIGURE 24. 8-BIT SYSTEM COMPONENTS
4-1079
HI1175 Static Performance Definitions
Offset, full scale, and gain all use a measured value of the internal voltage reference to determine the ideal plus and minus full scale values. The results are all displayed in LSBs. Offset Error (EOB) The first code transition should occur at a level 1/2 LSB above the bottom reference voltage. Offset is defined as the deviation of the actual code transition from this point. Note that this is adjustable to zero. Full Scale Error (EOT) The last code transition should occur for a analog input that is 11/2 LSBs below full scale. 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. The converter is guaranteed to have no missing codes. 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. Total Harmonic Distortion This is the ratio of the RMS sum of the first 5 harmonic components to the RMS value of the measured input signal. 2nd and 3rd Harmonic Distortion This is the ratio of the RMS value of the 2nd and 3rd harmonic component respectively to the RMS value of the measured 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. If the harmonics are buried in the noise floor it is the largest peak. Full Power Input Bandwidth Full power bandwidth is the 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 a peak-to-peak amplitude equal to the reference voltage. The bandwidth given is measured at the specified sampling frequency.
Dynamic Performance Definitions
Fast Fourier Transform (FFT) techniques are used to evaluate the dynamic performance of the HI1175. A low distortion sine wave is applied to the input, it is sampled, and the output is stored in RAM. The data is then transformed into the frequency domain with a 1024 point FFT and analyzed to evaluate the dynamic performance of the A/D. The sine wave input to the part is -0.5dB down from fullscale for all these tests. The distortion numbers are quoted in dBc (decibels with respect to carrier) and DO NOT include any correction factors for normalizing to fullscale. 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 excluding DC. Effective Number Of Bits (ENOB) The effective number of bits (ENOB) is derived from the SINAD data. ENOB is calculated from: ENOB = (SINAD - 1.76 + VCORR) / 6.02, where: VCORR = 0.5dB.
Timing Definitions
Sampling Delay (tSD) Sampling 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) This is the RMS variation in the sampling delay due to variation of internal clock path delays. Data Latency (tLAT) After the analog sample is taken, the data on the bus is available after 2.5 cycles of the clock. This is due to the architecture 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 by 2.5 cycles. Output Data Delay (tD) Output Data Delay is the delay time from when the data is valid (rising clock edge) to when it shows up at the output bus. This is due to internal delays at the digital output.
4-1080
HI1175
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Intersil 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.
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Sales Office Headquarters
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