Overview
The AD8305ACPZ-RL7, produced by Analog Devices Inc., is a precision current-input logarithmic converter. This device is designed to provide a logarithmic output voltage proportional to the input current, making it highly suitable for applications requiring precise logarithmic conversion. The AD8305 operates over a wide dynamic range and can be used in various configurations, including log-ratio mode and as a precision comparator or threshold detector.
Key Specifications
| Parameter | Rating/Value |
|---|---|
| Logarithmic Slope | 10 mV/dB (nominal) |
| Logarithmic Intercept (Reference Current) | 1 nA (nominal) |
| Supply Voltage (VP - VN) | ≤ 12 V |
| Quiescent Current | 5.4 - 6.5 mA |
| Peak Source/Sink Current | 25 mA |
| Small Signal Bandwidth (GAIN = 1) | Up to 15 MHz |
| Slew Rate | 15 V/μs |
| Operating Temperature Range | −40°C to +85°C |
| Storage Temperature Range | −65°C to +150°C |
| Package Type | 16-lead LFCSP |
Key Features
- Precision current-input logarithmic conversion with a logarithmic slope of 10 mV/dB.
- Logarithmic intercept adjustable via an external resistor network.
- Buffer amplifier for driving substantial loads, implementing low-pass filters, or as a precision comparator.
- Rail-to-rail output stage with a peak current sourcing capacity of 25 mA.
- Operates in log-ratio mode with the numerator current applied to INPT and the denominator current applied to IREF.
- Wide operating temperature range from −40°C to +85°C.
Applications
- Logarithmic amplification in various signal processing applications.
- Threshold detection and precision comparator roles.
- Implementation of low-pass filters to manage noise at low current levels.
- Use in ADC systems to improve scaling accuracy with external reference voltage.
- General-purpose logarithmic conversion in industrial, medical, and communication systems.
Q & A
- What is the logarithmic slope of the AD8305?
The logarithmic slope of the AD8305 is 10 mV/dB.
- How is the logarithmic intercept adjusted?
The logarithmic intercept can be adjusted by varying the external resistor network connected to the reference input (IREF).
- What is the maximum supply voltage for the AD8305?
The maximum supply voltage (VP - VN) for the AD8305 is 12 V.
- What is the peak source/sink current capacity of the AD8305?
The peak source/sink current capacity of the AD8305 is 25 mA.
- What is the small signal bandwidth of the AD8305 at GAIN = 1?
The small signal bandwidth of the AD8305 at GAIN = 1 is up to 15 MHz.
- What is the operating temperature range of the AD8305?
The operating temperature range of the AD8305 is −40°C to +85°C.
- Can the AD8305 operate in log-ratio mode?
Yes, the AD8305 can operate in log-ratio mode with the numerator current applied to INPT and the denominator current applied to IREF.
- What is the package type of the AD8305ACPZ-RL7?
The AD8305ACPZ-RL7 comes in a 16-lead LFCSP package.
- How can the noise level at low currents be managed?
The noise level at low currents can be managed by using the buffer amplifier to realize low-pass filters.
- Can the AD8305 be used with external ADCs?
Yes, the AD8305 can be used with external ADCs to improve scaling accuracy, such as the AD7810, AD7823, and AD7813.
