ADVFC32

REV.B

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REV.B 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. a ADVFC32 Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 2000 Voltage-to-Frequency and Frequency-to-Voltage Converter

FEATURES

/H115500.01% Max at 10 kHz FS /H115500.05% Max at 100 kHz FS /H115500.2% Max at 500 kHz FS Output TTL/CMOS-Compatible V/F or F/V Conversion

6 Decade Dynamic Range

Reliable Monolithic Construction MIL-STD-883-Compliant Versions Available PIN CONFIGURATION (TOP VIEW) PRODUCT DESCRIPTION The industry standard ADVFC32 is a low cost monolithic voltage-to-frequency (V/F) converter or frequency-to-voltage (F/V) converter with good linearity (0.01% max error at 10 kHz) and operating frequency up to 0.5 MHz. In the V/F configuration, positive or negative input voltages or currents can be converted to a proportional frequency using only a few external compo- nents. For F/V conversion, the same components are used with a simple biasing network to accommodate a wide range of input logic levels. TTL or CMOS compatibility is achieved in the V/F operating mode using an open collector frequency output. The pull-up resistor can be connected to voltages up to 30 volts, or to 15 V or 5 V for conventional CMOS or TTL logic levels. This resis- tor should be chosen to limit current through the open collector output to 8 mA. A larger resistance can be used if driving a high impedance load. Input offset drift is only 3 ppm of full scale per °C, and full- scale calibration drift is held to a maximum of 100 ppm/ °C (ADVFC32BH) due to a low T.C. Zener diode. The ADVFC32 is available in commercial, industrial, and extended temperature grades. The commercial grade is pack- aged in a 14-lead plastic DIP while the two wider temperature range parts are packaged in hermetically sealed 10-lead cans. PRODUCT HIGHLIGHTS 1. The ADVFC32 uses a charge balancing circuit technique (see Functional Block Diagram) which is well suited to high accuracy voltage-to-frequency conversion. The full-scale operating frequency is determined by only one precision resistor and capacitor. The tolerance of other support compo- nents (including the integration capacitor) is not critical. Inexpensive ± 20% resistors and capacitors can be used with- out affecting linearity or temperature drift. 2. The ADVFC32 is easily configured to satisfy a wide range of system requirements. Input voltage scaling is set by selecting the input resistor which sets the input current to 0.25 mA at the maximum input voltage. 3. The same components used for V/F conversion can also be used for F/V conversion by adding a simple logic biasing network and reconfiguring the ADVFC32. 4. The ADVFC32 is intended as a pin-for-pin replacement for VFC32 devices from other manufacturers. 5. The ADVFC32 is available in versions compliant with MIL- STD-883. Refer to the Analog Devices Military Products Databook or current ADVFC32/883B data sheet for detailed specifications.

REV. B–2– ADVFC32–SPECIFICATIONS(typical @ 25/H11543C with VS = /H1155015 V unless otherwise noted.) ADVFC32K ADVFC32B ADVFC32S Model Min Typ Max Min Typ Max Min Typ Max Unit DYNAMIC PERFORMANCE Full-Scale Frequency Range 0 500 0 500 0 500 kHz Nonlinearity 1 Full-Scale Calibration Error (Adjustable to Zero) ± 5 ± 5 ± 5% vs. Supply vs. Temperature (Full-Scale Frequency = 10 kHz) ± 75 –100 +100 +150 +150 ppm/°C DYNAMIC RESPONSE Maximum Settling Time for Full Scale Step Input 1 Pulse of New Frequency Plus 1 µs 1 Pulse of New Frequency Plus 1 µs 1 Pulse of New Frequency Plus 1 µs Overload Recovery Time 1 Pulse of New Frequency Plus 1 µs 1 Pulse of New Frequency Plus 1 µs 1 Pulse of New Frequency Plus 1 µs ANALOG INPUT AMPLIFIER (V/F Conversion) Current Input Range 0 0.25 0 0.25 0 0.25 mA Voltage Input Range 0 –10 0 –10 0 –10 V 2 0.25 0.25 0.25 mA × RIN 3 × RIN 3 × RIN Differential Impedance 300 kΩ||10 pF 2 MΩ||10 pF 300 k Ω||10 pF 2 M Ω||10 pF 300 k Ω||10 pF 2 M Ω||10 pF Common-Mode Impedance 300 M Ω||3 pF 750 M Ω||3 pF 300 M Ω||3 pF 750 M Ω||10 pF 300 M Ω||3 pF 750 M Ω||10 pF Input Bias Current Noninverting Input 40 250 40 250 40 250 nA Inverting Input –100 ± 8 +100 –100 ± 8 +100 –100 ± 8 +100 nA Input Offset Voltage (Trimmable to Zero) 2, 3 44 4 mV vs. Temperature (T MIN to TMAX)3 0 3 0 30 µV/°C Safe Input Voltage ± VS ± VS ± VS COMPARATOR (F/V Conversion) Logic “0” Level –V S –0.6 –V S –0.6 –V S –0.6 V Logic “1” Level 1 +V S 1+ V S 1+ V S V Input Impedance 50 k Ω||10 pF 250 k Ω 50 kΩ||10 pF 250 k Ω 50 kΩ||10 pF 250 k Ω OPEN COLLECTOR OUTPUT (V/F Conversion) Output Voltage in Logic “0” ISINK = 8 mA 0.4 0.4 0.4 V Output Leakage Current in Logic “1” 11 1 µA Voltage Range 0 30 0 30 0 30 V Fall Times (Load = 500 pF and ISINK = 5 mA) 400 400 400 ns AMPLIFIER OUTPUT (F/V Conversion) Voltage Range (0 mA ≤IO≤7 mA) 0 10 0 10 0 10 V Source Current (0 ≤VO≤7 V) 10 10 10 mA Capacitive Load (Without Oscillation) 100 100 100 pF Closed Loop Output Impedance 1 1 1 Ω POWER SUPPLY Rated Voltage ± 15 ± 15 ± 15 V Voltage Range ± 9 ± 18 ± 9 ± 18 ± 9 ± 18 V Quiescent Current 6 8 6 8 6 8 mA TEMPERATURE RANGE Specified Range 0 +70 –25 +85 –55 +125 °C Operating Range –25 +85 –55 +125 –55 +125 °C Storage –25 +85 –65 +150 –65 +150 °C PACKAGE OPTIONS Plastic DIP (N-14) ADVFC32KN TO–100 (H-10A) ADVFC32BH ADVFC32SH NOTES 1Nonlinearity defined as deviation from a straight line from zero to full scale, expressed as a percentage of full scale. 2See Figure 3. 3See Figure 1. 4fMAX expressed in units of MHz. Specifications shown in boldface are tested on all production units at final electrical test. Results from those tests are used to calculate outgoing quality l evels. All min and max specifications are guaranteed, although only those shown in boldface are tested on all production units. Specifications subject to change without notice.

magnitude to the 1 mA internal current source. Figure 1. At the start of a cycle, a current proportional to the Figure 1. Connection Diagram for V/F Conversion, Figure 2. Voltage-to-Frequency Conversion Waveforms perature coefficients are not critical.

10 V 100 kHz 330 pF 40 k Ω 1000 pF

recommended to avoid performance degradation or loss of functionality.

ence and resistor should be used to minimize offset drift errors. by the switched 1 mA current source so that no net effect occurs. bipolar input ranges, or F/V conversion. amp in most applications, two key differences should be noted. amplifier must be buffered if large sink currents are required. including offset and gain calibration cycles. A/D conversion will be as accurate as the references provided. from the relatively low impedance ADVFC32 input. Figure 5. High Resolution, Self-Calibrating, Microprocessor Operated A/D Converter

Figure 6. High Noise Immunity Data Link Dimensions shown in inches and (mm). no power or ground connections need to be made. is approximately 2 kHz, and the output noise is less than 15 mV. filter is recommended as an output stage. the output of the F/V converter.