Analog Devices AD684SQ, AD684JQ, AD684AQ Datasheet

a		Four-Channel
		Sample-and-Hold Amplifier
		AD684*
	FEATURES	FUNCTIONAL BLOCK DIAGRAM
	Four Matched Sample-and-Hold Amplifiers
	Independent Inputs, Outputs and Control Pins
	500 ns Hold Mode Settling
	1 ms Maximum Acquisition Time to 0.01%
	Low Droop Rate: 0.01 mV/ms
	Internal Hold Capacitors
	75 ps Maximum Aperture Jitter
	Low Power Dissipation: 430 mW
	0.3" Skinny DIP Package
	MIL-STD-883 Compliant Versions Available

PRODUCT DESCRIPTION

The AD684 is a monolithic quad sample-and-hold amplifier (SHA). It features four complete sampling channels, each controlled by an independent hold command. Each SHA is complete with an internal hold capacitor. The high accuracy SHA channels are self-contained and require no external components or adjustments. The AD684 is manufactured on a BiMOS process which provides a merger of high performance bipolar circuitry and low power CMOS logic.

The AD684 is ideal for high performance, multichannel data acquisition systems. Each SHA channel can acquire a signal in less than 1 μs and retain the held value with a droop rate of less than 0.01 μV/μs. Excellent linearity and ac performance make the AD684 an ideal front end for high speed 12and 14-bit ADCs.

The AD684 has a self-correcting architecture that minimizes hold mode errors and insures accuracy over temperature. Each channel of the AD684 is capable of sourcing 5 mA and incorporates output short circuit protection.

The AD684 is specified for three temperature ranges. The J grade device is specified for operation from 0 to +70°C, the A grade from –40°C to +85°C and the S grade from –55°C to +125°C.

*Protected by U.S. Patent Number 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.

PRODUCT HIGHLIGHTS

1.Fast acquisition time (1 μs) and low aperture jitter (75 ps) make the AD684 the best choice for multiple channel data acquisition systems.

2.Monolithic construction insures excellent interchannel matching in terms of timing and accuracy, as well as high reliability.

3.Independent inputs, outputs and sample-and-hold controls allow user flexibility in system architecture.

4.Low droop (0.01 μV/μs) and internally compensated hold mode error results in superior system accuracy.

5.The AD684’s fast settling time and low output impedance make it ideal for driving high speed analog to digital converters such as the AD578, AD674, AD7572 and the AD7672.

6.The AD684 is available in versions compliant with MIL- STD-883. Refer to the Analog Devices Military Products Databook or current AD684/883B data sheet for detailed specifications.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: [phone] Fax: [phone]

AD684–SPECIFICATIONS (TMIN to TMAX with VCC = +12 V 6 10%, VEE = –12 V 6 10%, unless otherwise noted)

		AD684J			AD684A			AD684S
Parameter	Min	Typ	Max	Min	Typ	Max	Min	Typ	Max	Units
SAMPLING CHARACTERISTICS
Acquisition Time										μs
10 V Step to 0.01%		0.75	1.0		0.75	1.0		0.75	1.0
10 V Step to 0.1%		0.5	0.6		0.5	0.6		0.5	0.6	μs
Small Signal Bandwidth		4			4			4		MHz
Full Power Bandwidth		1			1			1		MHz
HOLD CHARACTERISTICS
Effective Aperture Delay	–35	–25	–15	–35	–25	–15	–35	–25	–15	ns
Aperture Jitter		50	75		50	75		50	75	ps
Hold Settling Time (to 1 mV)		250	500		250	500		250	500	ns
Droop Ratel		0.01	1		0.01	1		0.01	1	μV/μs
Feedthrough
(VIN = ± 5 V, 100 kHz)		–90			–90			–90		dB
ACCURACY CHARACTERISTICS1	–4		+3	–4		+3	–4		+3
Hold Mode Offset		–1			1			–1		mV
Hold Mode Offset Drift		10	200		10	200		10	200	μV/°C
Sample Mode Offset		50			50			50		mV
Nonlinearity		±0.002	±0.003		±0.002	±0.003		±0.003	±0.005	% FS
Gain Error		±0.03	60.05		±0.03	60.05		±0.03	60.05	% FS
INTERCHANNEL CHARACTERISTICS
Interchannel Isolation
(VIN = ±5 V, 100 kHz)	80	86		80	86		80	86		dB
Interchannel Aperture Offset		150	300		150	300		150	300	ps
Interchannel Offset		0.4	1.5		0.4	2.0		0.4	2.0	mV
OUTPUT CHARACTERISTICS
Output Drive Current2	–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										μV rms
(dc to 5 MHz)		150			150			150
Sampled dc Uncertainty		85			85			85		μV rms
Hold Mode Noise										μV rms
(dc to 5 MHz)		125			125			125
Short Circuit Current3
Source		20			20			20		mA
Sink		10			10			10		mA
INPUT CHARACTERISTICS
Input Voltage Range	–5		+5	–5		+5	–5		+5	V
Bias Current4		100	250		100	250		100	250	nA
			400			500			500	nA
Input Impedance		50			50			50		MΩ
Input Capacitance		2			2			2		pF
DIGITAL CHARACTERISTICS			0.8			0.8			0.8
Input Voltage Low	2.0			2.0			2.0			V
Input Voltage High										V
Input Current (VIN = 5 V)		2	10		2	10		2	10	μA
POWER SUPPLY CHARACTERISTICS	±10.8	±12	±13.2	±10.8	±12	±13.2	±10.8	±12	±13.2
Operating Voltage Range (VCC, VEE)										V
Supply Current	65	18	25	65	18	25	65	18	26	mA
+PSRR		70			70			70		dB
–PSRR	60	65		60	65		60	65		dB
Power Consumption		430	600		430	600		430	625	mW
TEMPERATURE RANGE										°C
Specified Performance	0		+70	–40		+85	–55		+125
PACKAGE OPTIONS
16-Pin Cerdip (Q)		AD684JQ		AD684AQ			AD684SQ

NOTES

1Specified and tested over an input range of ±5 V.

2Maximum current the AD684 can source (or sink). Testing guarantees that the accuracy of the held signal remains within 2.5 mV of its initial value. 3The output is protected for a short circuit to common, VCC and VEE .

4VCC and VEE at nominal voltage levels.

Specifications shown in boldface are tested on all production units 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 on all production units.

Specifications subject to change without notice.

–2–

REV. A

AD684

PIN CONFIGURATION

ABSOLUTE MAXIMUM RATINGS*

	With
Spec	Respect to	Min	Max	Unit
VCC	Common	–0.3	+15	V
VEE	Common	–15	+0.3	V
Control Inputs	Common	–0.5	+7	V
Analog Inputs	Common	–12	+12	V
Output Short Circuit to
Ground, VCC or VEE		Indefinite
Max Junction				°C
Temperature			+175
Storage		–65	+150	°C
Lead Temperature				°C
(10 sec max)			+300
Power Dissipation			640	mW

*Stresses above those listed under “Absolute Maximum Ratings” may cause permanent 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.

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 AD684 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.

ORDERING GUIDE

		Package
Model1	Temperature Range	Option2
AD684JQ	0 to +70°C	Q-16
AD684AQ	–40°C to +85°C	Q-16
AD684SQ	–55°C to +125°C	Q-16

NOTES

1For details on grade and package offerings screened in accordance with MIL-STD-883, refer to the Analog Devices Military Products Databook or current AD684/883B data sheet.

2Q = Cerdip.

WARNING!

ESD SENSITIVE DEVICE

REV. A

–3–