The AD537 is a monolithic V-F converter consisting of an input amplifier, a precision oscillator system, an accurate internal reference generator and a high current output stage. Only a single external RC network is required to set up any full-scale (F.S.) frequency up to 100 kHz and any F.S. input voltage up to ±30 V. Linearity error is as low as ±0.05% for 10 kHz F.S., and operation is guaranteed over an 80 dB dynamic range. The overall temperature coefficient (excluding the effects of external components) is typically ±30 ppm/°C. The AD537 operates from a single supply of 5 V to 36 V and consumes only 1.2 mA quiescent current.

A temperature-proportional output, scaled to 1.00 mV/K, enables the circuit to be used as a reliable temperature-to-frequency converter; in combination with the fixed reference output of 1.00 V, offset scales such as 0°C or 0°F can be generated.

The low drift (1µV/°C typ) input amplifier allows operation directly from small signals (e.g., thermocouples or strain gages) while offering a high (250 M(Ohm) input resistance. Unlike most V-F converters, the AD537 provides a square-wave output, and can drive up to 12 TTL loads, LEDs, very long cables, etc.

The excellent temperature characteristics and long-term stability of the AD537 are guaranteed by the primary bandgap reference generator and the low T.C. silicon chromium thin film resistors used throughout.

The device is available in either a TO-116 ceramic DIP or a TO-100 metal can; both are hermetically sealed packages.

The AD537 is available in three performance/temperature grades; the J and K grades are specified for operation over the 0°C to +70°C range while the AD537S is specified for operation over the extended temperature range, -55°C to +125°C.

*Protected by Patent Nos. 3,88,963 and RE 20,586.

Part#	Architecture	# Channels	Input Voltage Range (V)	Full Scale Fout (kHz)	Reference Voltage (V)	Accuracy (%/kHz)	Input Clk Frequency (MHz)	Voltage Supply (V)	Supply Current (max)	Package	Price* (1000-4999)
AD537	Non-Synchronous	1-Single Ended	±11	150	1	0.25	-	+/- 5 to +/- 18	2.5	14-Lead CerDIP	$9.65
AD650	Non-Synchronous	1-Single Ended	+11	1000	-	0.1	-	+/- 9 to +/- 18	8	14-Lead CerDIP, 14-Lead PDIP, 20-Lead PLCC	$8.02
AD652	Synchronous	1-Single Ended	±10	2500	5	2	5	+/- 6 to +/- 15	15	20-Lead PLCC	$9.92
AD654	Non-Synchronous	1-Single Ended	±14	500	-	0.4	-	+/- 5 to +/- 18	2.5	8-Lead PDIP, 8-Lead SOIC	$3.76
AD7740	Synchronous	1-Single Ended	+2.5	500	2.5	1	1	3 to 5.25	1.5	8-Lead MSOP, 8-Lead SOT-23	$0.91
AD7741	Synchronous	1-Single Ended	+2.5	3072	2.5	2	6.144	4.75 to 5.25	8	8-Lead PDIP, 8-Lead SOIC	$1.76
AD7742	Synchronous	2-Differential, 3-Pseudo Differential	+3.5	3072	2.5	2	6.144	4.75 to 5.25	8	16-Lead PDIP, 16-Lead SOIC	-
ADVFC32	Non-Synchronous	1-Single Ended	+10	500	-	0.2	-	+/- 9 to +/- 18	8	14-Lead PDIP	$6.14

* The pricing listed here is provided only for budgetary purposes as recommended list price in U.S. Dollars in the United States ex factor per unit for the stated volume. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
** Pricing is currently unavailable. Click on the product number to see the Product Page for additional information.

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• Pre-Release: The model has not been released to general production, but samples may be available.
• Production: The model is currently being produced, and generally available for purchase and sampling.
• Last Time Buy: The model has been scheduled for obsolescence, but may still be purchased for a limited time.
• Obsolete: The specific part is obsolete and no longer available. Other models listed in the table may still be available (if they have a status that is not obsolete).

The package for this IC (i.e. DIP, SOIC, BGA). An Evaluation Board is a board engineered to show the performance of the model, the part is included on the board.

For detailed drawings and chemical composition please consult our  Package Site

Pin Count is the number of pins, balls, or pads on the device. Pin-out diagrams & pin function descriptions may be found in the datasheet.

This is the acceptable operating range of the device. The various ranges specified are as follows:

• Commercial: 0 to +70 degrees Celsius
• Military : -55 to +125 degrees Celsius
• Industrial: Temperature ranges may vary by model. Please consult the datasheet for more information.
• Automotive: -40 to +125 degrees Celsius

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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