AD652 Analog Devices Data Manual/Specifications Sheet

Monolithic Synchronous Voltage-to-Frequency Converter

AD652

FEATURES The AD652 is available in five performance grades. The 20-lead Full-scale frequency (up to 2 MHz) set by external system PLCC-packaged JP and KP grades are specified for operation clock over the 0°C to +70°C commercial temperature range. The

Extremely low linearity error (0.005% max at 1 MHz FS, 16-lead CERDIP-packaged AQ and BQ grades are specified for 0.02% max at 2 MHz FS) operation over the −40°C to +85°C industrial temperature No critical external components required

range. The AD652SQ is available for operation over the full

Accurate 5 V reference voltage

−55°C to +125°C extended temperature range.

Low drift (25 ppm/°C max)

Dual- or single-supply operation PRODUCT HIGHLIGHTS

Voltage or current input 1. The use of an external clock to set the full-scale frequency MIL-STD-883 compliant versions available allows the AD652 to achieve linearity and stability far

superior to other monolithic VFCs. By using the same clock

PRODUCT DESCRIPTION

to drive the AD652 and set the counting period (through a

The AD652 synchronous voltage-to-frequency converter

suitable divider), conversion accuracy is maintained

(SVFC) is a powerful building block for precision analog-to-

independent of variations in clock frequency.

digital conversion, offering typical nonlinearity of 0.002%

2. The AD652 synchronous VFC requires only one external

(0.005% maximum) at a 100 k Hz output frequency. The inher-

component (a noncritical integrator capacitor) for

ent monotonicity of the transfer function and wide range of

operation.

clock frequencies allow the conversion time and resolution to

be optimized for specific applications. 3. The AD652 includes a buffered, accurate 5 V reference. 4. The AD652’s clock input is TTL and CMOS compatible and

The AD652 uses a variation of the charge-balancing technique

can also be driven by sources referred to the negative power

to perform the conversion function. The AD652 uses an

supply. The flexible open-collector output stage provides

external clock to define the full-scale output frequency, rather

www.BDTIC.com/ADI

sufficient current sinking capability for TTL and CMOS

than relying on the stability of an external capacitor. The result

logic, as well as for optical couplers and pulse transformers.

is a more stable, more linear transfer function, with significant

A capacitor-programmable one-shot is provided for selec-

application benefits in both single- and multichannel systems.

tion of optimum output pulse width for power reduction.

Gain drift is minimized using a precision low drift reference

5. The AD652 can also be configured for use as a synchronous

and low TC, on-chip, thin-film scaling resistors. Furthermore,

F/V converter for isolated analog signal transmission.

initial gain error is reduced to less than 0.5% by the use of laser-

wafer-trimming. 6. The AD652 is available in versions compliant with MILSTD-883. Refer to the Analog Devices Military

The analog and digital sections of the AD652 have been

Products Databook or current AD652/883B data sheet for

designed to allow operation from a single-ended power source,

detailed specifications.

simplifying its use with isolated power supplies.

FUNCTIONAL BLOCK DIAGRAM

CLOCK IN

RIN COMPARATOR

VIN D FLOP LATCH

CK ONE SHOT

AND QD

INTEGRATOR

Figure 1.

Rev. C 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 that may result from its use.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Specifications subject to change without notice. No license is granted by implication

or otherwise under any patent or patent rights of Analog Devices. Trademarks and Tel: 781.329.4700 www.analog.com registered trademarks are the property of their respective owners. Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.