Overview
The AD652BQ, produced by Analog Devices Inc., is a monolithic synchronous voltage-to-frequency converter (SVFC) designed for precision analog-to-digital conversion. This device is a powerful building block for various applications requiring accurate and stable frequency output based on input voltage. The AD652BQ uses a charge-balancing technique and an external clock to define the full-scale output frequency, ensuring high linearity and stability. It is available in a 16-lead CERDIP package and is specified for operation over the −40°C to +85°C industrial temperature range.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Gain Error (fCLOCK = 200 kHz) | ±0.5% | ±1% | ±0.25% | % |
| Gain Error (fCLOCK = 1 MHz) | ±0.5% | ±1% | ±0.25% | % |
| Gain Error (fCLOCK = 4 MHz) | ±0.5% | ±1.5% | ±0.25% | % |
| Gain Temperature Coefficient (fCLOCK = 200 kHz) | ±25 | ±50 | ±15 | µV/°C |
| Open-Loop Gain | 86 | 86 | dB | |
| Common-Mode Input Range | −VS + 5 | +VS − 5 | V | |
| CMRR | 80 | 80 | dB | |
| Bandwidth | 14 | 95 | MHz | |
| Output Voltage Range | −1 (+VS − 4) | V (Referred to Pin 6, R1 >= 5 kΩ) | ||
| Comparator Input Bias Current | 0.5 | 5 | µA | |
| Clock Input Maximum Frequency | 4 | 5 | MHz | |
| Clock Input Threshold Voltage | 1.2 | V |
Key Features
- External Clock for Full-Scale Frequency: The AD652BQ uses an external clock to set the full-scale output frequency, ensuring high linearity and stability.
- Low Linearity Error: The device offers extremely low linearity error, with a maximum of 0.005% at 1 MHz full-scale frequency and 0.02% at 2 MHz full-scale frequency.
- No Critical External Components: Only one noncritical external component (an integrator capacitor) is required for operation.
- Accurate 5 V Reference Voltage: Includes a buffered, accurate 5 V reference voltage.
- Low Drift and High Accuracy: Features low drift (25 ppm/°C max) and high accuracy due to precision low drift reference and on-chip thin-film scaling resistors.
- Dual- or Single-Supply Operation: Can operate from a single-ended power source, simplifying use with isolated power supplies.
- TTL and CMOS Compatible Clock Input: The clock input is compatible with both TTL and CMOS logic levels.
Applications
- Precision Analog-to-Digital Conversion: Ideal for applications requiring high accuracy and stability in analog-to-digital conversion.
- Single- and Multichannel Systems: Suitable for both single- and multichannel systems due to its inherent monotonicity and wide range of clock frequencies.
- Frequency-to-Voltage Conversion: Can be used in frequency-to-voltage converter configurations.
- Delta Modulator and Bridge Transducer Interface: Applicable in delta modulator circuits and bridge transducer interfaces.
- Isolated Front End and A-to-D Conversion: Useful in isolated front-end applications and general A-to-D conversion needs.
Q & A
- What is the primary function of the AD652BQ?
The AD652BQ is a synchronous voltage-to-frequency converter, converting input voltage to a corresponding frequency output.
- What is the significance of using an external clock in the AD652BQ?
The external clock allows the AD652BQ to achieve high linearity and stability in its output frequency, independent of variations in clock frequency.
- What is the maximum linearity error of the AD652BQ at 1 MHz full-scale frequency?
The maximum linearity error at 1 MHz full-scale frequency is 0.005%.
- What type of package does the AD652BQ come in?
The AD652BQ is available in a 16-lead CERDIP package.
- What is the operating temperature range for the AD652BQ?
The AD652BQ operates over the −40°C to +85°C industrial temperature range.
- Does the AD652BQ require any critical external components?
No, the AD652BQ requires only one noncritical external component, an integrator capacitor, for operation.
- Is the AD652BQ compatible with both TTL and CMOS logic levels?
Yes, the clock input of the AD652BQ is compatible with both TTL and CMOS logic levels.
- What is the typical gain error of the AD652BQ at 200 kHz clock frequency?
The typical gain error at 200 kHz clock frequency is ±1%.
- Can the AD652BQ operate from a single power supply?
Yes, the AD652BQ can operate from a single-ended power source, simplifying its use with isolated power supplies.
- What are some common applications of the AD652BQ?
The AD652BQ is commonly used in precision analog-to-digital conversion, single- and multichannel systems, frequency-to-voltage conversion, delta modulator circuits, and bridge transducer interfaces..
