Analog Devices AD573JD, AD573SD, AD573KP, AD573KN, AD573KD Datasheet

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10-Bit A/D Converter

AD573*

FEATURES

Complete 10-Bit A/D Converter with Reference, Clock and Comparator

Full 8- or 16-Bit Microprocessor Bus Interface

Fast Successive Approximation Conversion—20 ms typ

No Missing Codes Over Temperature Operates on +5 V and –12 V to –15 V Supplies Low Cost Monolithic Construction

FUNCTIONAL BLOCK DIAGRAM

	V+	V–	DIGITAL		CONVERT
			COMMON
ANALOG	5k					MSB
						DB9
IN
ANALOG						DB8
COMMON			10-BIT	10-BIT		DB7
			CURRENT	SAR
			OUTPUT
						DB6	HIGH
			DAC
	COMP-					DB5	BYTE
	ARATOR					DB4
					INT
BIPOLAR				CLOCK		DB3
OFFSET						DB2
CONTROL
						DB1	LOW
						DB0	BYTE
						LSB
						HBE
		BURIED ZENER REF				LBE
DATA					AD573
READY

PRODUCT DESCRIPTION

The AD573 is a complete 10-bit successive approximation analog-to-digital converter consisting of a DAC, voltage reference, clock, comparator, successive approximation register (SAR) and three state output buffers—all fabricated on a single chip. No external components are required to perform a full accuracy 10-bit conversion in 20 μs.

The AD573 incorporates advanced integrated circuit design and processing technologies. The successive approximation function is implemented with I2L (integrated injection logic). Laser trimming of the high stability SiCr thin-film resistor ladder network insures high accuracy, which is maintained with a temperature compensated subsurface Zener reference.

Operating on supplies of +5 V and –12 V to –15 V, the AD573 will accept analog inputs of 0 V to +10 V or –5 V to +5 V. The trailing edge of a positive pulse on the CONVERT line initiates the 20 μs conversion cycle. DATA READY indicates completion of the conversion. HIGH BYTE ENABLE (HBE) and LOW BYTE ENABLE (LBE) control the 8-bit and 2-bit three state output buffers.

The AD573 is available in two versions for the 0°C to +70°C temperature range, the AD573J and AD573K. The AD573S guarantees ±1 LSB relative accuracy and no missing codes from –55°C to +125°C.

Three package configurations are offered. All versions are offered in a 20-pin hermetically sealed ceramic DIP. The AD573J and AD573K are also available in a 20-pin plastic DIP or 20-pin leaded chip carrier.

*Protected by U.S. Patent Nos. 3,940,760; 4,213,806; 4,136,349; 4,400,689; and 4,400,690.

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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

l.The AD573 is a complete 10-bit A/D converter. No external components are required to perform a conversion.

2.The AD573 interfaces to many popular microprocessors without external buffers or peripheral interface adapters. The

10bits of output data can be read as a 10-bit word or as 8- and 2-bit words.

3.The device offers true 10-bit accuracy and exhibits no missing codes over its entire operating temperature range.

4.The AD573 adapts to either unipolar (0 V to +10 V) or bipolar (–5 V to +5 V) analog inputs by simply grounding or opening a single pin.

5.Performance is guaranteed with +5 V and –12 V or –15 V supplies.

6.The AD573 is available in a version compliant with MIL-STD-

883.Refer to the Analog Devices Military Products Databook or current /883B data sheet for detailed specifications.

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

		(@ TA = +258C, V+ = +5 V, V– = –12 V or –15 V, all voltages measured with respect
AD573–SPECIFICATIONS to digital common, unless otherwise noted.)
		AD573J			AD573K			AD573S
Model	Min	Typ	Max	Min	Typ	Max	Min	Typ	Max	Units
RESOLUTION		10			10			10		Bits
RELATIVE ACCURACY1			61			61/2			61	LSB
TA = TMIN to TMAX			61			61/2			61	LSB
FULL-SCALE CALIBRATION2		±2			±2				62	LSB
UNIPOLAR OFFSET			61			61/2			61	LSB
BIPOLAR OFFSET			61			61/2			61	LSB
DIFFERENTIAL NONLINEARITY3	10			10			10			Bits
TA = TMIN to TMAX	9			10			10			Bits
TEMPERATURE RANGE	0		+70	0		+70	–55		+125	°C
TEMPERATURE COEFFICIENTS4
Unipolar Offset			62			61			62	LSB
Bipolar Offset			62			61			62	LSB
Full-Scale Calibration2			64			62			65	LSB
POWER SUPPLY REJECTION
Positive Supply
+4.5 V ≤ V + ≤ +5.5 V			62			61			62	LSB
Negative Supply
–15.75 V ≤ V – ≤ –14.25 V			62			61			62	LSB
–12.6 V ≤ V – ≤ –11.4 V			62			61			62	LSB
ANALOG INPUT IMPEDANCE	3.0	5.0	7.0	3.0	5.0	7.0	3.0	5.0	7.0	kΩ
ANALOG INPUT RANGES
Unipolar	0		+10	0		+10	0		+10	V
Bipolar	–5		+5	–5		+5	–5		+5	V
OUTPUT CODING
Unipolar	Positive True Binary			Positive True Binary			Positive True Binary
Bipolar	Positive True Offset Binary			Positive True Offset Binary			Positive True Offset Binary
LOGIC OUTPUT
Output Sink Current
(VOUT = 0.4 V max, TMIN to TMAX)	3.2			3.2			3.2			mA
Output Source Current5
(VOUT = 2.4 V min, TMIN to TMAX)	0.5			0.5			0.5			mA
Output Leakage			640			640			640	μA
LOGIC INPUTS										μA
Input Current			6100			6100			6100
Logic “1”	2.0			2.0			2.0			V
Logic “0”			0.8			0.8			0.8	V
CONVERSION TIME										μs
TA = TMIN to TMAX	10	20	30	10	20	30	10	20	30
POWER SUPPLY
V+	+4.5	5.0	+7.0	+4.5	+5.0	+7.0	+4.5	+5.0	+7.0	V
V–	–11.4	–15	–16.5	+11.4	–15	–16.5	–11.4	–15	–16.5	V
OPERATING CURRENT
V+		15	20		15	20		15	20	mA
V–		9	15		9	15		9	15	mA

NOTES

1Relative accuracy is defined as the deviation of the code transition points from the ideal transfer point on a straight line from the zero to the full scale of the device. 2Full-scale calibration is guaranteed trimmable to zero with an external 50 Ω potentiometer in place of the 15 Ω fixed resistor. Full scale is defined as 10 volts minus 1 LSB, or 9.990 volts.

3Defined as the resolution for which no missing codes will occur. 4Change from +25°C value from +25°C to TMIN or TMAX.

5The data output lines have active pull-ups to source 0.5 mA. The DATA READY line is open collector with a nominal 6 kΩ internal pull-up resistor.

Specifications subject to change without notice.

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.

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AD573

	ABSOLUTE MAXIMUM RATINGS
	V+ to Digital Common . . . . . . . . . . . . .		. . . . . . . . 0 V to +7 V
	V– to Digital Common . . . . . . . . . . . . .		. . . . . . 0 V to –16.5 V
	Analog Common to Digital Common . .		. . . . . . . . . . . .	. ±1 V
	Analog Input to Analog Common . . . . .		. . . . . . . . . . . .	±15 V
	Control Inputs . . . . . . . . . . . . . . . . . . . .		. . . . . . . . . . 0	V to V+
	Digital Outputs (High Impedance State)		. . . . . . . . . . 0	V to V+
	Power Dissipation . . . . . . . . . . . . . . . . .		. . . . . . . . . . . 800 mW
	ORDERING GUIDE1
	Package Option2		Temperature			Relative
Model			Range			Accuracy
AD573JN	20-Pin Plastic DIP (N-20)		0°C to +70°C			±1 LSB max
AD573KN	20-Pin Plastic DIP (N-20)		0°C to +70°C			±1/2 LSB max
AD573JP	20-Pin Leaded Chip Carrier (P-20A)		0°C to +70°C			±1 LSB max
AD573KP	20-Pin Leaded Chip Carrier (P-20A)		0°C to +70°C			±1/2 LSB max
AD573JD	20-Pin Ceramic DIP (D-20)		0°C to +70°C			±1 LSB max
AD573KD	20-Pin Ceramic DIP (D-20)		0°C to +70°C			±1/2 LSB max
AD573 SD	20-Pin Ceramic DIP (D-20)		–55°C to +125°C			±1 LSB max

NOTES

1For details on grade and package offerings screened in accordance with MIL-STD-883, refer to Analog Devices Military Products Databook.

2D = Ceramic DIP; N = Plastic DIP; P = Plastic Leaded Chip Carrier.

FUNCTIONAL DESCRIPTION

A block diagram of the AD573 is shown in Figure 1. The positive CONVERT pulse must be at least 500 ns wide. DR goes high within 1.5 μs after the leading edge of the convert pulse indicating that the internal logic has been reset. The negative edge of the CONVERT pulse initiates the conversion. The internal 10-bit current output DAC is sequenced by the integrated injection logic (I2L) successive approximation register (SAR) from its most significant bit to least significant bit to provide an output current which accurately balances the input signal current through the 5 kΩ resistor. The comparator determines whether the addition of each successively weighted bit current causes the DAC current sum to be greater or less than the input current; if the sum is more, the bit is turned off. After testing all bits, the SAR contains a 10-bit binary code which accurately represents the input signal to within 1/2 LSB (0.05% of full scale).

The SAR drives DR low to indicate that the conversion is complete and that the data is available to the output buffers. HBE and LBE can then be activated to enable the upper 8-bit and lower 2-bit buffers as desired. HBE and LBE should be brought high prior to the next conversion to place the output buffers in the high impedance state.

The temperature compensated buried Zener reference provides the primary voltage reference to the DAC and ensures excellent stability with both time and temperature. The bipolar offset input controls a switch which allows the positive bipolar offset current (exactly equal to the value of the MSB less 1/2 LSB) to be injected into the summing (+) node of the comparator to offset the DAC output. Thus the nominal 0 V to +10 V unipolar input range becomes a –5 V to +5 V range. The 5 kΩ thin-film input resistor is trimmed so that with a full-scale input signal, an input current will be generated which exactly matches the DAC output with all bits on.

	V+	V–	DIGITAL		CONVERT
			COMMON
ANALOG	5k					MSB
						DB9
IN
ANALOG						DB8
COMMON			10-BIT	10-BIT		DB7
			CURRENT
					SAR
			OUTPUT
						DB6	HIGH
			DAC
							BYTE
	COMP-					DB5
	ARATOR					DB4
					INT
BIPOLAR				CLOCK		DB3
OFFSET						DB2
CONTROL
						DB1	LOW
						DB0	BYTE
						LSB
						HBE
		BURIED ZENER REF				LBE
DATA					AD573
READY

Figure 1. Functional Block Diagram

UNIPOLAR CONNECTION

The AD573 contains all the active components required to perform a complete A/D conversion. Thus, for many applications, all that is necessary is connection of the power supplies (+5 V and –12 V to –15 V), the analog input and the convert pulse. However, there are some features and special connections which should be considered for achieving optimum performance. The functional pinout is shown in Figure 2.

The standard unipolar 0 V to +10 V range is obtained by shorting the bipolar offset control pin (Pin 16) to digital common (Pin 17).

REV. A

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