Analog Devices AD736JR-REEL-7, AD736JR-REEL, AD736JR, AD736JN, AD736BQ Datasheet

a		Low Cost, Low Power,
		True RMS-to-DC Converter
		AD736

FEATURES

COMPUTES

True RMS Value

Average Rectified Value

Absolute Value

PROVIDES

200 mV Full-Scale Input Range

(Larger Inputs with Input Attenuator) High Input Impedance of 1012 V

Low Input Bias Current: 25 pA max

High Accuracy: 60.3 mV 60.3% of Reading

RMS Conversion with Signal Crest Factors Up to 5 Wide Power Supply Range: +2.8 V, –3.2 V to 616.5 V Low Power: 200 mA max Supply Current

Buffered Voltage Output

No External Trims Needed for Specified Accuracy AD737—An Unbuffered Voltage Output Version with

Chip Power Down Is Also Available

FUNCTIONAL BLOCK DIAGRAM

which allows the measurement of 300 mV input levels, while operating from the minimum power supply voltage of +2.8 V, –3.2 V. The two inputs may be used either singly or differentially.

PRODUCT DESCRIPTION

The AD736 is a low power, precision, monolithic true rms-to-dc converter. It is laser trimmed to provide a maximum error of ±0.3 mV ±0.3% of reading with sine-wave inputs. Furthermore, it maintains high accuracy while measuring a wide range of input waveforms, including variable duty cycle pulses and triac (phase) controlled sine waves. The low cost and small physical size of this converter make it suitable for upgrading the performance of non-rms “precision rectifiers” in many applications. Compared to these circuits, the AD736 offers higher accuracy at equal or lower cost.

The AD736 can compute the rms value of both ac and dc input voltages. It can also be operated ac coupled by adding one external capacitor. In this mode, the AD736 can resolve input signal levels of 100 μV rms or less, despite variations in temperature or supply voltage. High accuracy is also maintained for input waveforms with crest factors of 1 to 3. In addition, crest factors as high as 5 can be measured (while introducing only 2.5% additional error) at the 200 mV full-scale input level.

The AD736 has its own output buffer amplifier, thereby providing a great deal of design flexibility. Requiring only 200 μA of power supply current, the AD736 is optimized for use in portable multimeters and other battery powered applications.

The AD736 allows the choice of two signal input terminals: a high impedance (1012 Ω) FET input which will directly interface with high Z input attenuators and a low impedance (8 kΩ) input

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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.

The AD736 achieves a 1% of reading error bandwidth exceeding 10 kHz for input amplitudes from 20 mV rms to 200 mV rms while consuming only 1 mW.

The AD736 is available in four performance grades. The AD736J and AD736K grades are rated over the commercial temperature range of 0°C to +70°C. The AD736A and AD736B grades are rated over the industrial temperature range of –40°C to +85°C.

The AD736 is available in three low-cost, 8-pin packages: plastic mini-DIP, plastic SO and hermetic cerdip.

PRODUCT HIGHLIGHTS

1.The AD736 is capable of computing the average rectified value, absolute value or true rms value of various input signals.

2.Only one external component, an averaging capacitor, is required for the AD736 to perform true rms measurement.

3.The low power consumption of 1 mW makes the AD736 suitable for many battery powered applications.

4.A high input impedance of 1012 Ω eliminates the need for an external buffer when interfacing with input attenuators.

5.A low impedance input is available for those applications requiring up to 300 mV rms input signal operating from low power supply voltages.

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

(@ +258C 65 V supplies, ac coupled with 1 kHz sine-wave input applied unless

AD736–SPECIFICATIONS otherwise noted.)

				AD736J/A			AD736K/B
Model			Conditions	Min	Typ	Max	Min	Typ	Max	Units
TRANSFER FUNCTION				VOUT =	Avg.(V IN	2 )	VOUT =	Avg.(V IN	2 )
CONVERSION ACCURACY			1 kHz Sine Wave
	Total Error, Internal Trim1		ac Coupled Using CC			0.5/0.5			0.3/0.3	±mV/±% of Reading
	All Grades		0–200 mV rms		0.3/0.3			0.2/0.2
	TMIN–TMAX		200 mV–1 V rms		–1.2	62.0		–1.2	62.0	% of Reading
						0.7/0.7			0.5/0.5	±mV/±% of Reading
	A&B Grades		@ 200 mV rms
	J&K Grades		@ 200 mV rms		0.007			0.007		±% of Reading/°C
	vs. Supply Voltage		VS = ±5 V to ±16.5 V	0		+0.1	0		+0.1
	@ 200 mV rms Input				+0.06			+0.06		%/V
	@ 200 mV rms Input		VS = ±5 V to ±3 V	0	–0.18	–0.3	0	–0.18	–0.3	%/V
	dc Reversal Error, dc Coupled		@ 600 mV dc		1.3	2.5		1.3	2.5	% of Reading
	Nonlinearity2, 0 mV–200 mV		@ 100 mV rms	0	+0.25	+0.35	0	+0.25	+0.35	% of Reading
	Total Error, External Trim		0–200 mV rms		0.1/0.5			0.1/0.3		±mV/±% of Reading
	ERROR vs. CREST FACTOR3		CAV, CF = 100 μF
	Crest Factor 1 to 3				0.7			0.7		% Additional Error
	Crest Factor = 5		CAV, CF = 100 μF		2.5			2.5		% Additional Error
INPUT CHARACTERISTICS
	High Impedance Input (Pin 2)
	Signal Range					200			200
	Continuous rms Level		VS = +2.8 V, –3.2 V							mV rms
	Continuous rms Level		VS = ±5 V to ±16.5 V	60.9		1	60.9		1	V rms
	Peak Transient Input		VS = +2.8 V, –3.2 V		±2.7			±2.7		V
	Peak Transient Input		VS = ±5 V							V
	Peak Transient Input		VS = ±16.5 V	64.0			64.0			V
	Input Resistance		VS = ±3 V to ±16.5 V		1012	25		1012	25	Ω
	Input Bias Current				1			1		pA
	Low Impedance Input (Pin 1)
	Signal Range
	Continuous rms Level		VS = +2.8 V, –3.2 V			300			300	mV rms
	Continuous rms Level		VS = ±5 V to ±16.5 V		±1.7	l		±1.7	l	V rms
	Peak Transient Input		VS = +2.8 V, –3.2 V							V
	Peak Transient Input		VS = ±5 V		±3.8			±3.8		V
	Peak Transient Input		VS = ±16.5 V		±11			±11		V
	Input Resistance			6.4	8	9.6	6.4	8	9.6	kΩ
	Maximum Continuous					±12			±12
	Nondestructive Input		All Supply Voltages							V p-p
	Input Offset Voltage4		ac Coupled			63			63
	J&K Grades									mV
	A&B Grades					63			63	mV
	vs. Temperature		VS = ±5 V to ±16.5 V		8	30		8	30	μV/°C
	vs. Supply				50	150		50	150	μV/V
	vs. Supply		VS = ±5 V to ±3 V		80			80		μV/V
OUTPUT CHARACTERISTICS
	Output Offset Voltage				±0.1	60.5		±0.1	60.3
	J&K Grades									mV
	A&B Grades					60.5			60.3	mV
	vs.Temperature		VS = ±5 V to ±16.5 V		1	20		1	20	μV/°C
	vs. Supply				50	130		50	130	μV/V
	Output Voltage Swing		VS = ±5 V to ±3 V		50			50		μV/V
	2 kΩ Load		VS = +2.8 V, –3.2 V	0 to +1.6	+1.7		0 to +1.6	+1.7		V
	2 kΩ Load		VS = ±5 V	0 to +3.6	+3.8		0 to +3.6	+3.8		V
	2 kΩ Load		VS = ±16.5 V	0 to +4	+5		0 to +4	+5		V
	No Load		VS = ±16.5 V	0 to +4	+12		0 to +4	+12		V
	Output Current			2			2			mA
	Short-Circuit Current				3			3		mA
	Output Resistance		@ dc		0.2			0.2		Ω
FREQUENCY RESPONSE
	High Impedance Input (Pin 2)
	For 1% Additional Error		Sine-Wave Input
	VIN = 1 mV rms				1			1		kHz
	VIN = 10 mV rms				6			6		kHz
	VIN = 100 mV rms				37			37		kHz
	VIN = 200 mV rms				33			33		kHz

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AD736

			AD736J/A		AD736K/B
Model	Conditions	Min	Typ	Max	Min	Typ	Max	Units
±3 dB Bandwidth	Sine-Wave Input
VIN = 1 mV rms			5			5		kHz
VIN = 10 mV rms			55			55		kHz
VIN = 100 mV rms			170			170		kHz
VIN = 200 mV rms			190			190		kHz
FREQUENCY RESPONSE
Low Impedance Input (Pin 1)
For 1% Additional Error	Sine-Wave Input
VIN = 1 mV rms			1			1		kHz
VIN = 10 mV rms			6			6		kHz
VIN = 100 mV rms			90			90		kHz
VIN = 200 mV rms			90			90		kHz
±3 dB Bandwidth	Sine-Wave Input
VIN = l mV rms			5			5		kHz
VIN = 10 mV rms			55			55		kHz
VIN = 100 mV rms			350			350		kHz
VIN = 200 mV rms			460			460		kHz
POWER SUPPLY		+2.8, –3.2 ±5		±16.5		±5	±16.5
OperatingVoltageRange					+2.8, –3.2			Volts
Quiescent Current	Zero Signal		160	200		160	200	μA
200 mV rms, No Load	Sine-Wave Input		230	270		230	270	μA
TEMPERATURE RANGE
Operating, Rated Performance
Commercial (0°C to +70°C)			AD736J			AD736K
Industrial (–40°C to +85°C)			AD736A			AD736B

NOTES

lAccuracy is specified with the AD736 connected as shown in Figure 16 with capacitor CC.

2Nonlinearity is defined as the maximum deviation (in percent error) from a straight line connecting the readings at 0 and 200 mV rms. Output offset voltage is adjusted to zero. 3Error vs. Crest Factor is specified as additional error for a 200 mV rms signal. C.F. = VPEAK/V rms.

4DC offset does not limit ac resolution.

Specifications are 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.

ABSOLUTE MAXIMUM RATINGS1

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±16.5 V Internal Power Dissipation2 . . . . . . . . . . . . . . . . . . . . .200 mW

Input Voltage . . . . . . . . . . . . . . . . . . . . . . . ±VS Output Short-Circuit Duration . . . . . . . . . . . . . . . . . Indefinite

Differential Input Voltage . . . . . . . . . . . . . . . . . . +VS and –VS Storage Temperature Range (Q) . . . . . . –65°C to +150°C Storage Temperature Range (N, R) . . . . . –65°C to +125°C Operating Temperature Range

AD736J/K . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C AD736A/B . . . . . . . . . . . . . . . . . . . . . . . . . .–40°C to +85°C

ORDERING GUIDE

	Temperature	Package	Package
Model	Range	Description	Option
AD736JN	0°C to +70°C	Plastic Mini-DIP	N-8
AD736KN	0°C to +70°C	Plastic Mini-DIP	N-8
AD736JR	0°C to +70°C	Plastic SOIC	SO-8
AD736KR	0°C to +70°C	Plastic SOIC	SO-8
AD736AQ	–40°C to +85°C	Cerdip	Q-8
AD736BQ	–40°C to +85°C	Cerdip	Q-8
AD736JR-REEL	0°C to +70°C	Plastic SOIC	SO-8
AD736JR-REEL-7	0°C to +70°C	Plastic SOIC	SO-8
AD736KR-REEL	0°C to +70°C	Plastic SOIC	SO-8
AD736KR-REEL-7	0°C to +70°C	Plastic SOIC	SO-8

Lead Temperature Range (Soldering 60 sec) . . . . . . . . +300°C ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 V

NOTES

1Stresses 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. Exposure to absolute maximum rating conditions for extended periods may affect device reliability .

28-Pin Plastic Package: θJA = 165°C/W

8-Pin Cerdip Package: θJA = 110°C/W

8-Pin Small Outline Package: θJA = 155°C/W

PIN CONFIGURATION

8-Pin Mini-DIP (N-8), 8-Pin SOIC (R-8),

8-Pin Cerdip (Q-8)

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