Analog Devices AD7118UQ, AD7118TQ, AD7118LN, AD7118KN, AD7118CQ Datasheet

a		LOGDAC
		CMOS Logarithmic D/A Converter
		AD7118*

FEATURES

Dynamic Range 85.5 dB Resolution 1.5 dB

Full 625 V Input Range Multiplying DAC

Full Military Temperature Range –558C to +1258C

Low Distortion

Low Power Consumption

Latch Proof Operation (Schottky Diodes Not Required) Single 5 V to 15 V Supply

APPLICATIONS

Digitally Controlled AGC Systems

Audio Attenuators

Wide Dynamic Range A/D Converters

Sonar Systems

Function Generators

GENERAL DESCRIPTION

The LOGDAC® AD7118 is a CMOS multiplying D/A converter which attenuates an analog input signal over the range

0 to –85.5 dB in 1.5 dB steps. The analog output is determined by a six-bit attenuation code applied to the digital inputs. Operating frequency range of the device is from dc to several hundred kHz.

The device is manufactured using an advanced monolithic silicon gate thin-film on CMOS process and is packaged in a 14-pin dual-in-line package.

FUNCTIONAL DIAGRAM

PIN CONFIGURATION

ORDERING INFORMATION

		Specified
	Temperature	Accuracy	Package
Model	Range	Range	Option1
AD7118KN	0°C to +70°C	0 to 42 dB	N-16
AD7118LN	0°C to +70°C	0 to 48 dB	N-16
AD7118BQ	–25°C to +85°C	0 to 42 dB	Q-16
AD7118CQ	–25°C to +85°C	0 to 48 dB	Q-16
AD7118TQ2	–55°C to +125°C	0 to 42 dB	Q-16
AD7118UQ2	–55°C to +125°C	0 to 48 dB	Q-16

NOTES

1N = Plastic DIP; Q = Cerdip.

2To order MIL-STD-883, Class B processed parts, add /883B to part number.

*Protected by U.S. Patent No. 4521,764.

LOGDAC is a registered trademark of Analog Devices, Inc.

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: [phone] Fax: [phone]

	AD7118–SPECIFICATIONS			(VDD = +5 V or +15 V, VIN = –10 V dc, IOUT = AGND = DGND = 0 V, output amplifier
				AD544 except where noted)
			TA = +258C				TA = TMIN, TMAX
	Parameter		VDD = +5 V		VDD = +15 V		VDD = +5 V		VDD = +15 V	Units	Test Conditions/Comments
	NOMINAL RESOLUTION		1.5		1.5		1.5		1.5	dB
	ACCURACY RELATIVE TO VIN
	AD7118L/C/U		±0.35		±0.35		±0.4		±0.4
	0 dB to –30 dB									dB max	Accuracy is measured using
	–31.5 dB to –42 dB		±0.7		±0.5		±0.8		±0.7	dB max	circuit of Figure 1 and includes
	–43.5 dB to –48 dB		±1.0		±0.7		±1.3		±1.0	dB max	any effects due to mismatch
	AD7118K/B/T		±0.5		±0.5		±0.5		±0.5		between RFB and the R-2R
	0 dB to –30 dB									dB max	ladder circuit.
	–31.5 dB to –42 dB		±0.75		±0.75		±1.0		±0.8	dB max
	MONOTONIC RANGE
	Nominal 1.5 dB Steps	L/C/U Grade	Monotonic Over Full				0 to –72		0 to –72	dB	Digital Inputs 000000 to 110000
		K/B/T Grade	Code Range				0 to –66		0 to –66	dB	Digital Inputs 000000 to 101100
	Nominal 3 dB Steps	All Grades	Monotonic Over Full Code Range
	VIN INPUT RESISTANCE	All Grades	9		9		9		9	kW min
	(PIN 12)	L/C/U Grade	17		17		17		17	kW max
		K/B/T Grade	21		21		21		21	kW max
	RFB INPUT RESISTANCE	All Grades	9.45		9.45		9.45		9.45	kW min
	(PIN 13)	L/C/U Grade	18		18		18		18	kW max
		K/B/T Grade	22		22		22		22	kW max
	DIGITAL INPUTS
	Input High Voltage Requirements VIH		3.0		13.5		3.0		13.5	V min
	Input Low Voltage Requirements VIL		0.8		1.5		0.8		1.5	V max
	Input Leakage Current		±1		±1		±10		±10	mA max	Digital Inputs = VDD
	POWER SUPPLY
	VDD for Specified Accuracy		5		–		5		–	V min
			–		15		–		15	V max
	IDD		0.5		1		1		2	mA max	Digital Inputs = 0 V or VDD
											(See Figure 7)
	Specifications subject to change without notice.					(VDD = +5 V or +15 V, VIN = –10 V except where stated, IOUT = AGND = DGND =
	AC PERFORMANCE CHARACTERISTICS
						0 V, output amplifier AD544 except where noted)

These characteristics are included for design guidance only and are not subject to test.

		TA = +258C		TA = TMIN, TMAX
Parameter		VDD = +5 V	VDD = +15 V	VDD = +5 V	VDD = +15 V	Units
DC Supply Rejection, DGain/DVDD		0.01	0.005	0.01	0.005	dB per % max			DVDD = ±10%,
						ms max			Input code = 100000
Propagation Delay		1.8	0.4	2.2	0.5				Full-Scale Change
Digital-to-Analog Glitch Impulse		225	1200	–	–	nV secs typ			Measured with ADLH0032CG
									as output amplifier for input
									code transition 100000 to 000000.
									C1 of Figure 1 is 0 pF.
Output Capacitance (Pin 14)		100	100	100	100	pF max
Input Capacitance Pin 12 and Pin 13		7	7	7	7	pF max
Feedthrough at 1 kHz	L/C/U Grade	–86	–86	–68	–68	dB max			Feedthrough is also deter-
	K/B/T Grade	–80	–80	–63	–63	dB max			mined by circuit layout
Total Harmonic Distortion		–85	–85	–85	–85	dB typ			VIN = 6 V rms
Intermodulation Distortion		–79	–79	–79	–79	dB typ			per DIN 45403 Blatt 4
Output Noise Voltage Density		70	70	70	70	nV/Ö	Hz	max	Includes AD544 amplifier noise
Digital Input Capacitance		7	7	7	7	pF max

Specifications subject to change without notice.

Accuracy Specification for K/B/T Grade Devices at TA = +25°C	Accuracy Specification for L/C/U Grade Devices at TA = +25°C
–2–	REV. A