DATEL ADS-118, ADS-118A Service Manual

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®
®
INNOV A TION and EX CELLENCE
REGISTER
REGISTER
3-STATE OUTPUT REGISTER
DIGITAL CORRECTION LOGIC
SUPPLY
GROUND
SUPPLY
GROUND
查询ADS-118供应商查询ADS-118供应商
FEATURES
12-bit resolution
5MHz minimum sampling rate
Functionally complete
Small 24-pin DDIP
Requires only ±5V supplies
Low-power, 1.3 Watts
No missing codes over full military temperature range
Edge-triggered, no pipeline delay
Ideal for both time and frequency-domain applications
GENERAL DESCRIPTION
DATEL's ADS-118 and ADS-118A are 12-bit, 5MHz, sampling A/D converters packaged in space-saving 24-pin DDIP’s. The ADS-118 offers an input range of ±1V and has three-state outputs. The ADS-118A has an input range of ±1.25V and features direct adjustment of offset error.
These functionally complete low-power devices (1.3 Watts) contain an internal fast-settling sample/hold amplifier, a 12-bit subranging A/D converter, a precise voltage reference, timing/ control logic, and error-correction circuitry. All timing and control logic operates from the rising edge of a single start convert pulse. Digital input and output levels are TTL. Models are available for use in either commercial (0 to +70°C) or military (–55 to +125°C) operating temperature ranges.
Applications include radar, transient signal analysis, process control, medical/graphic imaging, and FFT spectrum analysis.
ADS-118, ADS-118A
12-Bit, 5MHz, Low-Power
Sampling A/D Converters
INPUT/OUTPUT CONNECTIONS
PIN FUNCTION PIN FUNCTION
1 BIT 12 (LSB) 24 NO CONNECTION 2 BIT 11 23 ANALOG GROUND 3 BIT 10 22 NO CONNECTION 4 BIT 9 21 +5V ANALOG SUPPLY 5 BIT 8 20 –5V SUPPLY 6 BIT 7 19 ANALOG INPUT 7 BIT 6 18 ANALOG GROUND 8 BIT 5 17 ENABLE/OFFSET ADJ.
9 BIT 4 16 START CONVERT 10 BIT 3 15 EOC 11 BIT 2 14 DIGITAL GROUND 12 BIT 1 (MSB) 13 +5V DIGITAL SUPPLY
* ADS-118, Pin 17 is ENABLE
ADS-118A, Pin 17 is OFFSET ADJUST
*
OFFSET ADJUST 17
(ADS-118A only)
ANALOG INPUT 19
START CONVERT 16
EOC 15
21
+5V ANALOG
S/H
+
Σ
TIMING AND
CONTROL LOGIC
+5V DIGITAL
13
AMP
BUFFER
REF
FLASH
ADC
1
DAC
FLASH
ADC
2
14
DIGITAL
–5V SUPPLY
20
18, 23
ANALOG
22, 24
NO CONNECT
17 ENABLE
(ADS-118A only)
12 BIT 1 (MSB) 11 BIT 2 10 BIT 3 9 BIT 4 8 BIT 5 7 BIT 6 6 BIT 7 5 BIT 9 4 BIT 9 3 BIT 10 2 BIT 11 1 BIT 12 (LSB)
Figure 1. ADS-118/118A Functional Block Diagram
DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.) Tel: (508) 339-3000 Fax: (508) 339-6356 For immediate assistance: (800) 233-2765
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ADS-118/118A
® ®
ABSOLUTE MAXIMUM RATINGS
PARAMETERS LIMITS UNITS
+5V Supply (Pins 13, 21) 0 to +6 Volts –5V Supply (Pin 20) 0 to –6 Volts Digital Input (Pin 16, 17) –0.3 to +V Analog Input (Pin 19) ±5 Volts Lead Temperature (10 seconds) +300 °C
DD +0.3 Volts
PHYSICAL/ENVIRONMENTAL
PARAMETERS MIN. TYP. MAX. UNITS
Operating Temp. Range, Case
ADS-118/118AMC 0 +70 °C ADS-118/118AMM, GM, 883 –55 +125 °C
Thermal Impedance
θjc 2 °C/Watt θca 23 °C/Watt
Storage Temperature Range –65 +150 °C Package Type 24-pin, metal-sealed, ceramic DDIP or SMT
Weight 0.42 ounces (12 grams)
FUNCTIONAL SPECIFICATIONS
(TA = +25°C, ±VDD = ±5V, 5MHz sampling rate, and a minimum 3 minute warmup unless otherwise specified.)
+25°C 0 to +70°C –55 to +125°C
ANALOG INPUT MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS
Input Voltage Range, ADS-118 ±1 ±1 ±1 Volts Input Resistance 475 500 475 500 475 500 Input Capacitance 6 15 6 15 6 15 pF
DIGITAL INPUT
Logic Levels
Logic "1" +2.0 +2.0 +2.0 Volts Logic "0" +0.8 +0.8 +0.8 Volts Logic Loading "1" +20 +20 +20 µA Logic Loading "0" –20 –20 –20 µA
Start Convert Positive Pulse Width 50 100 50 100 50 100 ns
STATIC PERFORMANCE
Resolution 12 12 12 Bits Integral Nonlinearity (f Differential Nonlinearity (f
in = 10kHz) ±0.75 ±1.0 ±1.5 LSB
in = 10kHz) ±0.5 +0.75 ±0.5 ±0.95 ±0.75 +0.95 LSB
Full Scale Absolute Accuracy ±0.1 ±0.5 ±0.5 ±0.75 ±0.75 ±1.5 %FSR Bipolar Zero Error (Tech Note 2) ±0.1 ±0.5 ±0.5 ±0.85 ±0.85 ±2.0 %FSR Bipolar Offset Error (Tech Note 2) ±0.1 ±0.5 ±0.5 ±1.5 ±1.5 ±2.5 %FSR Gain Error (Tech Note 2) ±0.1 ±0.5 ±0.5 ±1.0 ±1.0 ±2.5 % No Missing Codes (f
in = 10kHz) 12 12 12 Bits
DYNAMIC PERFORMANCE
Peak Harmonics (–0.5dB)
dc to 500kHz –76 –71 –74 –70 –72 –66 dB 500kHz to 1MHz –75 –71 –74 –70 –70 –65 dB 1MHz to 2.5MHz –69 –69 –73 –67 –66 –60 dB
Total Harmonic Distortion (–0.5dB)
dc to 500kHz –72 –68 –71 –67 –70 –65 dB 500kHz to 1MHz –71 –67 –70 –66 –67 –63 dB 1MHz to 2.5MHz –70 –66 –69 –65 –66 –60 dB
Signal-to-Noise Ratio
(w/o distortion, –0.5dB) dc to 500kHz 67 69 66 69 64 67 dB 500kHz to 1MHz 66 69 65 68 63 66 dB 1MHz to 2.5MHz 66 69 65 68 63 66 dB
Signal-to-Noise Ratio
(& distortion, –0.5dB) dc to 500kHz 65 68 64 67 62 66 dB 500kHz to 1MHz 65 68 64 67 61 65 dB 1MHz to 2.5MHz 64 67 63 66 60 64 dB
Noise 195 195 195 µVrms Two-tone Intermodulation
Distortion (f
975kHz, f
in = 1MHz,
s = 5MHz, –0.5dB) –74 –74 –74 dB
Input Bandwidth (–3dB)
Small Signal (–20dB input) 20 20 20 MHz Large Signal (–0.5dB input) 10 10 10 MHz
Feedthrough Rejection (f
in = 2.5MHz) 80 80 80 dB
Slew Rate ±400 ±400 ±400 V/µs Aperture Delay Time +10 +10 +10 ns Aperture Uncertainty 3 3 3 ps rms
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ADS-118/118A
+25°C 0 to +70°C –55 to +125°C
DYNAMIC PERFORMANCE (Cont.) MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS
S/H Acquisition Time
( to ±0.001%FSR, 10V step) 85 90 85 90 85 90 ns
Overvoltage Recovery Time 200 200 200 ns A/D Conversion Rate 5 5 5 MHz
DIGITAL OUTPUTS
Logic Levels
Logic "1" +2.4 +2.4 +2.4 Volts Logic "0" +0.4 +0.4 +0.4 Volts Logic Loading "1" –4 –4 –4 mA Logic Loading "0" +4 +4 +4 mA
Delay, Falling Edge of EOC to
Output Data Valid 20 20 20 MHz
Delay, Falling Edge of ENABLE to
Output Data Valid 10 10 10 MHz
Output Coding
POWER REQUIREMENTS
Power Supply Ranges
+5V Supply +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 +4.9 +5.0 +5.25 Volts –5V Supply –4.75 –5.0 –5.25 –4.75 –5.0 –5.25 –4.9 –5.0 –5.25 Volts
Power Supply Currents
+5V Supply +205 +220 +205 +220 +205 +220 mA –5V Supply –80 –90 –80 –90 –80 –90 mA
Power Dissipation 1.3 1.5 1.3 1.5 1.3 1.5 Watts Power Supply Rejection ±0.1 ±0.1 ±0.1 %FSR/%V
Footnotes:
All power supplies should be on before applying a start convert pulse. All
supplies and the clock (start convert pulses) must be present during warmup periods. The device must be continuously converting during this time.
Input voltage ranges for ADS-118A is ±1.25VA 100ns wide start convert pulse is used for all production testing. For
applications requiring less than an 5MHz sampling rate, wider start convert pulses can be used. NOTE: The device only requires the rising edge of a start convert pulse to operate.
Effective bits is equal to:
This is the time required before the A/D output data is valid once the analog input
is back within the specified range.
The minimum supply voltages of +4.9V and –4.9V for ±V
–55°C operation only. The minimum limits are +4.75V and –4.75V when operating at +125°C
Offset Binary
(SNR + Distortion) – 1.76 + 20 log
Full Scale Amplitude
Actual Input Amplitude
6.02
DD are required for
TECHNICAL NOTES
1. Obtaining fully specified performance from the ADS-118 requires careful attention to pc-card layout and power supply decoupling. The device’s analog and digital ground systems are connected to each other internally. For optimal perfor­mance, tie all ground pins (14, 18, and 23) directly to a large analog ground plane beneath the package.
Bypass all power supplies to ground with 4.7µF tantalum capacitors in parallel with 0.1µF ceramic capacitors. Locate the bypass capacitors as close to the unit as possible.
2. The ADS-118 achieves its specified accuracies without the need for external calibration. If required, the device’s small initial offset and gain errors can be reduced to zero using
the adjustment circuitry shown in Figures 2a and 2b. When using this circuitry, or any similar offset and gain-calibration hardware, make adjustments following warmup. To avoid interaction, always adjust offset before gain.
3. To enable the three-state outputs, connect ENABLE (pin 17) to a logic "0" (low). To disable, connect pin 17 to logic "1" (high). The three-state outputs are permanently enabled in the ADS-118A.
4. Applying a start convert pulse while a conversion is in progress (EOC = logic "1") will initiate a new and inaccurate conversion cycle.
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ADS-118/118A
Potentiometer is at 25Ω during the device's factory trim procedure.
–15V (or –5V)
–15V
CALIBRATION PROCEDURE
Any offset and/or gain calibration procedures should not be implemented until devices are fully warmed up. To avoid interaction, offset must be adjusted before gain. The ranges of adjustment for the circuits in Figures 2a and 2b are guaranteed to compensate for the ADS-118's initial accuracy errors and may not be able to compensate for additional system errors.
A/D converters are calibrated by positioning their digital outputs exactly on the transition point between two adjacent digital output codes. This can be accomplished by connecting
LED’s to the digital outputs and adjusting until certain LED's "flicker" equally between on and off. Other approaches employ digital comparators or microcontrollers to detect when the outputs change from one code to the next.
For the ADS-118, offset adjusting is normally accomplished at the point where the MSB is a 1 and all other output bits are 0’s and the LSB just changes from a 0 to a 1. This digital output transition ideally occurs when the applied analog input is +½LSB (+244µV for ADS-118; +305µV for ADS-118A).
Gain adjusting is accomplished when all bits are 1’s and the LSB just changes from a 1 to a 0. This transition ideally occurs when the analog input is at +full scale minus 1½ LSB's (+0.99927V for ADS-118; +1.249085V for ADS-118A).
Zero/Offset Adjust Procedure
1. Apply a train of pulses to the START CONVERT input (pin 16) so the converter is continuously converting.
2. Apply +244µV (ADS-118) or +305µV (ADS-118A) to the ANALOG INPUT (pin 19).
® ®
3. Adjust the offset potentiometer until the output bits are 1000 0000 00000 and the LSB flickers between 0 and 1.
Gain Adjust Procedure
1. Apply +0.99927V (ADS-118) or +1.249085V (ADS-118A) to the ANALOG INPUT (pin 19).
2. Adjust the gain potentiometer until all output bits are 1's and the LSB flickers between 1 and 0.
3. To confirm proper operation of the device, vary the input signal to obtain the output coding listed in Table 1.
Table 1. Output Coding for Bipolar Operation
ADS-118 OUTPUT CODING ADS-118A
INPUT INPUT
BIPOLAR RANGE OFFSET BINARY RANGE
SCALE (±1V ) MSB LSB (±1.25V )
+FS –1 LSB +0.99951V 1111 1111 1111 +1.2494V
+3/4 FS +0.75000V 1110 0000 0000 +0.9375V +1/2 FS +0.50000V 1100 0000 0000 +0.6250V
0 0.00000V 1000 0000 0000 0.0000V –1/2 FS –0.50000V 0100 0000 0000 –0.6250V –3/4 FS –0.75000V 0010 0000 0000 –0.9375V
–FS +1 LSB –0.99951V 0000 0000 0001 –1.2494V
–FS –1.00000V 0000 0000 0000 –1.2500V
+15V
ZERO/ OFFSET ADJUST
SIGNAL
INPUT
–15V
20k
ADJUST
GAIN
50
1.2M
1.98k
Figure 2a. Optional ADS-118 External
Gain and Offset Adjust Circuits
2k
+15V
To Pin19 of ADS-118
GAIN
ADJUST
SIGNAL
INPUT
ZERO/ OFFSET ADJUST
50
+15V (or +5V)
20k
To Pin17 of ADS-118A
Figure 2b. Optional ADS-118A
Gain and Offset Adjust Circuits
To Pin19 of ADS-118A
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Note: Scale is approximately 10ns per division.
INTERNAL S/H
70ns max.
If separate supplies are used, the difference between the two cannot exceed 100mV.
+ +
+5V
–5V
BIT 1 (MSB)
14
4.7µF
4.7µF
0.1µF
0.1µF
ANALOG
INPUT
START
CONVERT
A single +5V supply should be used for both the +5V analog and +5V digital.
13, 21
20
18, 23
19
16
ADS-118
ADS-118A
12
BIT 2
11
BIT 3
10
BIT 4
9
BIT 5
8
BIT 6
7
BIT 7
6
BIT 8
5
BIT 9
4
BIT 10
3
BIT 11
2
BIT 12 (LSB)
1
EOC
15
ENABLE (1-12)
17
or OFFSET ADJUST
Figure 3. Typical Connection Diagram
ADS-118/118A
START
CONVERT
EOC
OUTPUT
DATA
N N+1
100ns typ.
10ns typ.
Hold
Acquisition Time
85ns typ.
90ns max.
35ns min., 40ns typ., 50ns max.
30ns, ±5ns
Conversion Time
140ns typ., 150ns max.
20ns typ.
DATA N-1 VALID DATA N VALID
130ns min.
INVALID DATA
150ns typ.
50ns typ.
Figure 4. ADS-118/118A Timing Diagram
INVALID DATA
5
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ADS-118/118A
Amplitude Relative to Full Scale (dB)
(fs = 5MHz, fin = 2.45MHz, Vin = –0.5dB, 4,096-point FFT)
Digital Output Code
Number of Occurences
DNL (LSB's)
THERMAL REQUIREMENTS
All DATEL sampling A/D converters are fully characterized and specified over operating temperature (case) ranges of 0 to +70°C and –55 to +125°C. All room temperature
A = +25°C) production testing is performed without the use
(T of heat sinks or forced air cooling. Thermal impedance figures for each device are listed in their respective specification tables.
These devices do not normally require heat sinks, however, standard precautionary design and layout procedures should be used to ensure devices do not overheat. The ground and power planes beneath the package, as well as all pcb signal runs to and from the device, should be as heavy as possible to help conduct heat away from the package.
0 –10 –20 –30 –40 –50 –60 –70 –80 –90
–100 –110 –120 –130
0 250 500 750 1 1.25 1.5 1.75 2 2.25 2.5
kHz kHz kHz MHz MHz MHz MHz MHz MHz MHz
® ®
Electrically-insulating, thermally-conductive "pads" may be installed underneath the package. Devices should be soldered to boards rather than socketed, and of course, minimal air flow over the surface can greatly help reduce the package temperature.
In more severe ambient conditions, the package/junction temperature of a given device can be reduced dramatically (typically 35%) by using one of DATEL's HS Series heat sinks. See Ordering Information for the assigned part number. See page 1-183 of the DATEL Data Acquisition Components Catalog for more information on the HS Series. Request DATEL Application Note AN8, "Heat Sinks for DIP Data Converters", or contact DATEL directly, for additional information.
Frequency
Figure 5. FFT Analysis of ADS-118
+0.67
0
–0.47
0
Digital Output Code
0
4096
4096
Figure 6. ADS-118 Histogram and Differential Nonlinearity
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®
ADS-118/118A
3
5
7
33
34
312729
323028
B1
(MSB)
B2
23
251921
262422
B4
B3
9
11
13
15
17
P1P1P1P1P1P1P1P1P1
P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1P1
20
B5
B6
14
16
18
B9
B8
B7
8
10
12
B12
B11
B10
(LSB) 6
4
JPR4
12
3
1
2
+15V
+5VF
NOTES:
1. UNLESS OTHERWISE SPECIFIED
P3
R6
1
C17
ALL CAPACITORS ARE 50V
START
CONVERT
2
SG4
1.2M
2
R2
2.2MF
C1-C6 ARE 20V
1
20K
+
74HCT573
ALL RESISTORS ARE IN OHMS
2. AS AN OPTION, COXIAL CABLE
C22
4.7MF
C20
3
19
20
2
BETWEEN THESE TWO POINTS.
+
OPTIONAL
-15V
17
18
3Q
2Q
1Q
3D
2D
1D
3
4
14
15
16
6Q
5Q
4Q
U3
6D
5D
4D
7
5
6
1
OELE
8Q
7Q
8D
7D
813
912
11
+5VF
17
18
19
3Q
2Q
2.2MF
+
20
2
74HCT573
1Q
3D
2D
1D
3
4
C16
10
+5VF
14
15
16
6Q
5Q
4Q
U2
6D
5D
4D
7
5
6
1
12
OELE
8Q
7Q
8D
7D
813
9
11
+5VF
10
Figure 7. ADS-118/118A Evaluation Board Schematic (ADS-B118)
1
2
3
4
5
6
7
8
9
10
11
1213
B9
B8
B7
B6
B5
B4
B3
B2
B1
U1
ADS-118/119
FOR ADS-119 10MHZ
FOR ADS-118/118A 5MHZ
X1
+5VF
14
8
C21
2
0.1MF
3
1
JPR3
+5VA
2K
R4
+15V
+5VD
TRIG
DGND
7
141516
+5V
R7
C18
SG6
SG5
ANAIN
50
119
118
2
3
1
JPR5
.1MF
OPTION
SEE NOTE 2
10
11
U4
4
5
SG9
R5
1.98K
1
+5VA
ENABLE
-5V
17
118A
SG8
SG7
R3
119
119
118
2
3
20K
OFFSET
181920
-5V
+5V
-5VA
-15V
21
222324
+5V
119A
118A
6
2
R1
+5VA
C19
GAIN
500
JPR6
3
119A
118A
JPR1
1
0.1MF
OPTION
SEE NOTE 2
B12
B11
B10
C15
+5VF
AGND
EOC
AGND
3
4
1
2
JPR2
-5VA
+5VA
C14
.01MF
C7
2.2MF
20MHY
L7,
L6
12
P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2P2
43
P4
INPUT
ANALOG
0.1MF
+15V
56
C13
0.01MF
C6
20MHY
87
14
2.2MF
L5
3
74HCT86
U5
7
1
2
+5V
C10
20MHY
L3
-15V
C12
0.01MF
C5
2.2MF
20MHY
L4
10 9
12 11
14 13
C3
0.01MF
2.2MF
-5VA
16 15
74HCT86
L1
C11
20MHY
9
+5VF
20MHY
0.01MF
C4
18 17
8
2.2MF
U5
10
C8
0.01MF
C1
20 19
2.2MF
6
11
U5
U5
74HCT86
4
5
-5V
C9
0.01MF
C2
2.2MF
20MHY
L2
SG1
SG2
22 21
24 23
26 25
SPARE GATES
12
13
SG3
7
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ADS-118/118A
INNOV A TION and EX CELLENCE
ISO 9001
REGISTERED
(2.540)
(1.016)
(unless otherwise indicated):
24-Pin DDIP
Versions
ADS-118MC ADS-118MM ADS-118AMC ADS-118AMM
MECHANICAL DIMENSIONS INCHES (mm)
1.31 MAX. (33.27)
0.235 MAX.
0.190 MAX. (4.826)
24
1 12
(5.969)
PIN 1 INDEX
0.018 ±0.002 (0.457)
1.100
(27.940)
0.100 TYP. (2.540)
0.100
(2.540)
0.040
(1.016)
13
0.80 MAX. (20.32)
0.200 MAX. (5.080)
SEATING
PLANE
(0.635)
0.025
Dimension Tolerances
2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127)
Lead Material: Kovar alloy Lead Finish:
over 100 microinches (nominal) nickel plating
0.600 ±0.010
(unless otherwise indicated):
50 microinches (minimum) gold plating
+0.002
0.010
–0.001
(0.254)
0.100
(15.240)
(2.540)
® ®
1.31 MAX. (33.02)
24-Pin
Surface Mount
Versions
0.190 MAX. (4.826)
24
PIN 1
INDEX
0.100 TYP.
0.020 TYP. (0.508)
0.040
13
0.80 MAX. (20.32)
121
0.100
(2.540)
Dimension Tolerances
2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127)
Lead Material: Kovar alloy Lead Finish: 50 microinches (minimum) gold plating
over 100 microinches (nominal) nickel plating
0.060 TYP. (1.524)
0.130 TYP. (3.302)
0.020
(0.508)
MAX. radius
0.010 TYP.
0.015
(0.381)
for any pin
(0.254)
ORDERING INFORMATION
MODEL NUMBER TEMP. RANGE PACKAGE
OPERATING 24-PIN
ADS-118MC 0 to +70°C DDIP ADS-118MM –55 to +125°C DDIP ADS-118AMC 0 to +70°C SMT ADS-118AMM –55 to +125°C SMT
Receptacles for PC board mounting can be ordered through AMP, Inc., Part # 3-331272-8 (Component Lead Socket), 24 required. For MIL-STD-883 product, or surface mount packaging, contact DATEL.
ACCESSORIES ADS-B118 Evaluation Board (without ADS-118)
HS-24 Heat Sink for all ADS-118 DDIP models
® ®
DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.
ISO 9001
DS-0231D 10/96
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