Analog Devices AD781SQ, AD781JN, AD781AN Datasheet
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45
6
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AD781
X1
V
CC
IN
COMMON
NC
OUT
S/H
NC
V
EE
Complete 700 ns
a
FEATURES
Acquisition Time to 0.01%: 700 ns Maximum
Low Power Dissipation: 95 mW
Low Droop Rate: 0.01 mV/ms
Fully Specified and Tested Hold Mode Distortion
Total Harmonic Distortion: –80 dB Maximum
Aperture Jitter: 75 ps Maximum
Internal Hold Capacitor
Self-Correcting Architecture
8-Pin Mini Cerdip and Plastic Package
MIL-STD-883 Compliant Versions Available
PRODUCT DESCRIPTION
The AD781 is a high speed monolithic sample-and-hold
amplifier (SHA). The AD781 guarantees a maximum
acquisition time of 700 ns to 0.01% over temperature. The
AD781 is specified and tested for hold mode total harmonic
distortion and hold mode signal-to-noise and distortion. The
AD781 is configured as a unity gain amplifier and uses a
self-correcting architecture that minimizes hold mode errors and
insures accuracy over temperature. The AD781 is self-contained
and requires no external components or adjustments.
The low power dissipation, 8-pin mini-DIP package and
completeness make the AD781 ideal for highly compact board
layouts. The AD781 will acquire a full-scale input in less than
700 ns and retain the held value with a droop rate of 0.01 µV/µs.
Excellent linearity and hold mode dc and dynamic performance
make the AD781 ideal for 12- and 14-bit high speed analogto-digital converters.
The AD781 is manufactured on Analog Devices’ BiMOS
process which merges high performance, low noise bipolar
circuitry with low power CMOS to provide an accurate, high
speed, low power SHA.
The AD781 is specified for three temperature ranges. The J
grade device is specified for operation from 0°C to +70°C, the A
grade from –40°C to +85°C and the S grade from –55°C to
+125°C. The J and A grades are available in 8-pin plastic DIP
packages. The S grade is available in an 8-pin cerdip package.
Sample-and-Hold Amplifier
AD781*
FUNCTIONAL BLOCK DIAGRAM
PRODUCT HIGHLIGHTS
1. Fast acquisition time (700 ns), low aperture jitter (75 ps) and
fully specified hold mode distortion make the AD781 an
ideal SHA for sampling systems.
2. Low droop (0.01 µV/µs) and internally compensated hold
mode error results in superior system accuracy.
3. Low power (95 mW typical), complete functionality and
small size make the AD781 an ideal choice for a variety of
high performance, low power applications.
4. The AD781 requires no external components or adjustments.
5. Excellent choice as a front-end SHA for high speed analogto-digital converters such as the AD671, AD7586, AD674B,
AD774B, AD7572 and AD7672.
6. Fully specified and tested hold mode distortion guarantees
the performance of the SHA in sampled data systems.
7. The AD781 is available in versions compliant with MILSTD-883. Refer to the Analog Devices Military Products
Databook or current AD781/883B data sheet for detailed
specifications.
*Protected by U.S. Patent No. 4,962,325.
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
AD781–SPECIFICA TIONS
(T
to T
DC SPECIFICATIONS
Parameter Min Typ Max Min Typ Max Min Typ Max Units
SAMPLING CHARACTERISTICS
Acquisition Time
10 V Step to 0.01% 600 700 600 700 600 700 ns
10 V Step to 0.1% 500 600 500 600 500 600 ns
Small Signal Bandwidth 4 4 4 MHz
Full Power Bandwidth 1 1 1 MHz
HOLD CHARACTERISTICS
Effective Aperture Delay (25°C) –35 –25 –15 –35 –25 –15 –35 –25 –15 ns
Aperture Jitter (25°C) 50 75 50 75 50 75 ps
Hold Settling (to 1 mV, 25°C) 250 500 250 500 250 500 ns
Droop Rate 0.01 1 0.01 1 0.01 1 µV/µs
Feedthrough (25°C)
(VIN = ±5 V, 100 kHz) –86 –86 –86 dB
ACCURACY CHARACTERISTICS
Hold Mode Offset –4 –1 +3 –4 –1 +3 –4 –1 +3 mV
Hold Mode Offset Drift 10 10 10 µV/°C
Sample Mode Offset 50 200 50 200 50 200 mV
Nonlinearity ±0.002 ±0.003 ±0.002 ±0.003 ±0.003 ±0.005 % FS
Gain Error ±0.01±0.025 ±0.01±0.025 ±0.01±0.025 % FS
OUTPUT CHARACTERISTICS
Output Drive Current –5 +5 –5 +5 –5 +5 mA
Output Resistance, DC 0.3 0.5 0.3 0.5 0.3 0.5 Ω
Total Output Noise (DC to 5 MHz) 150 150 150 µV rms
Sampled DC Uncertainty 85 85 85 µV rms
Hold Mode Noise (DC to 5 MHz) 125 125 125 µV rms
Short Circuit Current
Source 20 20 20 mA
Sink 10 10 10 mA
INPUT CHARACTERISTICS
Input Voltage Range –5 +5 –5 +5 –5 +5 V
Bias Current 50 250 50 250 50 250 nA
Input Impedance 50 50 50 MΩ
Input Capacitance 2 2 2 pF
DIGITAL CHARACTERISTICS
Input Voltage Low 0.8 0.8 0.8 V
Input Voltage High 2.0 2.0 2.0 V
Input Current High (VIN = 5 V) 2 10 2 10 2 10 µA
POWER SUPPLY CHARACTERISTICS
Operating Voltage Range ±10.8 ±12 ±13.2 ±10.8 ±12 ±13.2 ±10.8 ± 12 ±13.2 V
Supply Current 4 6.5 4 6.5 4 7 mA
+PSRR (+12 V ± 10%) 70 80 70 80 70 80 dB
–PSRR (–12 V ± 10%) 65 75 65 75 65 75 dB
Power Consumption 95 175 95 175 95 185 mW
TEMPERATURE RANGE
Specified Performance 0 +70 –40 +85 –55 +125 °C
NOTE
1
Specified and tested over an input range of ±5 V.
Specifications subject to change without notice.
Specifications shown in boldface are tested on all devices at final electrical test. Results from those tests are used to calculate outgoing quality levels. All min and max
specifications are guaranteed although only those shown in boldface are tested.
MIN
, VCC = +12 V 6 10%, VEE = –12 V 6 10%, CL = 20 pF, unless otherwise noted)
MAX
AD781J AD781A AD781S
1
–2–
REV. A
AD781
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AD781
TOP VIEW
(Not to Scale)
V
CC
IN
COMMON
NC
OUT
S/H
NC
V
EE
WARNING!
ESD SENSITIVE DEVICE
(T
to T
MIN
HOLD MODE AC SPECIFICATIONS
unless otherwise noted)
AD781J AD781A AD781S
Parameter Min Typ Max Min Typ Max Min Typ Max Units
TOTAL HARMONIC DISTORTION
F
= 10 kHz –90 –80 –90 –80 –90 –80 dB
IN
F
= 50 kHz –73 –73 –73 dB
IN
FIN = 100 kHz –68 –68 –68 dB
SIGNAL-TO-NOISE AND DISTORTION
F
= 10 kHz 72 78 72 78 72 78 dB
IN
F
= 50 kHz 73 73 73 dB
IN
FIN = 100 kHz 67 67 67 dB
INTERMODULATION DISTORTION
= 49 kHz, F
F
IN1
= 50 kHz
IN2
2nd Order Products –77 –77 –77 dB
3rd Order Products –78 –78 –78 dB
NOTE
1
FIN amplitude = 0 dB and F
Specifications shown in boldface are tested on all devices at final electrical test. Results from those tests are used to calculate outgoing quality levels. All min and max
specifications are guaranteed although only those shown in boldface are tested.
Specifications subject to change without notice.
= 500 kHz unless otherwise indicated.
SAMPLE
, VCC = +12 V 6 10%, VEE = –12 V 6 10%, CL = 20 pF,
MAX
1
ABSOLUTE MAXIMUM RATINGS*
PIN CONFIGURATION
With
Spec Respect to Min Max Unit
V
CC
V
EE
Common –0.3 +15 V
Common –15 +0.3 V
Control Input Common –0.5 +7 V
Analog Input Common –12 +12 V
Output Short Circuit to
Ground, V
CC
, or V
EE
Indefinite
Maximum Junction
Temperature +175 °C
Storage –65 +150 °C
Lead Temperature
(10 sec max) +300 °C
Power Dissipation 195 mW
*Stresses above those listed under “Absolute Maximum Ratings” may cause per-
manent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the
operational section of this specification is not implied.
Temperature Package
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Model
Range Description Options
AD781JN 0°C to +70°C 8-Pin Plastic DIP N-8
AD781AN –40°C to +85°C 8-Pin Plastic DIP N-8
AD781SQ –55°C to +125°C 8-Pin Cerdip Q-8
NOTES
1
For details on grade and package offerings screened in accordance with
MIL-STD-883, refer to the Analog Devices Military Products Databook or
current AD781/883B data sheet.
2
N = Plastic DIP; Q = Cerdip.
ORDERING GUIDE
CAUTION
ESD (electrostatic discharge) sensitive device. The digital control inputs are diode protected;
however, permanent damage may occur on unconnected devices subject to high energy electrostatic fields. Unused devices must be stored in conductive foam or shunts.
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REV. A
–3–
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