Part A
AD8306AR
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7304 ПКС
- Package
- SOIC-16
- Series
- Линейные - Усилители - Специальное назначение
Replacement verdict
Not a drop-in replacement
The AD8307AR and AD8306AR are not drop-in replacements for one another. Although both are logarithmic amplifiers in the same SOIC-8 package, they differ fundamentally in signal detection architecture, dynamic range, operating frequency, and output interface, so substituting one for the other requires circuit redesign and full validation.
Different detection architecture
Different dynamic range
Different frequency range
Different output interface
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8307AR | AD8306AR | Why it matters |
|---|---|---|---|
| Function | Logarithmic amplifier / RSSI detector (DC to 500 MHz) | Logarithmic limiting amplifier / RSSI detector (5 MHz to 400 MHz) | Defines the core signal-processing role; the AD8306 includes limiting amplifier outputs for phase/frequency demodulation, while the AD8307 is a pure log detector. |
| Frequency Range | DC to 500 MHz | 5 MHz to 400 MHz | Determines the input signal bandwidth the device can accurately process; the AD8307 extends to DC and higher frequency, while the AD8306 has a lower bound of 5 MHz. |
| Dynamic Range | 92 dB | 100 dB | Sets the span of input signal levels over which the logarithmic output remains usable; a wider range allows detection of weaker and stronger signals simultaneously. |
| Logarithmic Slope | 25 mV/dB | 20 mV/dB | Determines the output voltage change per dB of input; affects the scaling of the RSSI output and downstream ADC resolution requirements. |
| Logarithmic Intercept | -84 dBm (at 100 MHz) | -95 dBm (at 100 MHz) | Defines the reference point where the logarithmic output extrapolates to zero; critical for absolute power calibration and measurement accuracy. |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Both operate over the same supply range, allowing similar power-supply design; identical values indicate no substitution concern here. |
| Supply Current | 7.5 mA (typical) | 16 mA (typical) | Affects power consumption and thermal budget; the AD8306 draws roughly twice the current, which may impact battery-powered or thermally constrained designs. |
| Limiting Amplifier Outputs | Not available | Available (differential) | The AD8306 provides hard-limited outputs for FM/FSK demodulation and phase detection; the AD8307 lacks these, limiting its use to pure RSSI measurement. |
| Package | 8-Lead SOIC | 16-Lead SOIC | Footprint and pin count differ, so the two parts are not drop-in compatible on the same PCB without layout changes. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Both support industrial temperature ranges, so environmental tolerance is equivalent and not a differentiator for substitution. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8306AR | AD8307AR |
|---|---|---|
| Part Status | Obsolete | Obsolete |
| Type | Limiting-Logarithmic Amplifier | Logarithmic Amplifier |
| Applications | Receiver Signal Strength Indication (RSSI) | Receiver Signal Strength Indication (RSSI) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the primary functional differences between the AD8307AR and AD8306AR?
The AD8307AR is a 500 MHz, 92 dB logarithmic amplifier (log amp) designed for RSSI and signal strength measurement, providing a DC output proportional to the log of the input voltage. The AD8306AR is a 400 MHz, 100 dB limiting logarithmic amplifier with an integrated RSSI output and a hard-limited output, intended for received signal strength indication and phase/frequency demodulation in FM/FSK receivers. The AD8306AR includes a limiter output stage that the AD8307AR does not provide.
Are the AD8307AR and AD8306AR pin-compatible?
No. Both devices are offered in 8-lead SOIC packages, but their pin functions and internal architectures differ. The AD8307AR provides logarithmic and reference outputs, while the AD8306AR provides RSSI, limiter outputs, and additional control pins. They are not direct drop-in replacements and require separate PCB layouts.
What is the specified operating frequency range for each device?
The AD8307AR is specified for operation from DC to 500 MHz. The AD8306AR is specified for operation from DC to 400 MHz. Designs requiring operation above 400 MHz should use the AD8307AR, subject to verification against the manufacturer datasheet.
How do the dynamic ranges of the AD8307AR and AD8306AR compare?
The AD8307AR provides a nominal 92 dB dynamic range. The AD8306AR provides a nominal 100 dB dynamic range. The AD8306AR therefore offers approximately 8 dB greater logarithmic dynamic range, which can be advantageous in applications requiring wider signal strength measurement span.
Does the AD8306AR provide a limiter output that the AD8307AR lacks?
Yes. The AD8306AR includes a hard-limited output stage suitable for FM/FSK demodulation and phase detection, in addition to its RSSI output. The AD8307AR provides only a logarithmic (RSSI) output and does not include a limiter output.
What are the typical supply voltage and current requirements for these devices?
Both the AD8307AR and AD8306AR operate from a single supply in the range of 2.7 V to 5.5 V. Typical supply current for the AD8307AR is approximately 7.5 mA, while the AD8306AR typically draws approximately 16 mA due to its additional limiter circuitry. Exact values should be confirmed against the respective manufacturer datasheets.
Which device is better suited for RSSI measurement in a receiver AGC loop?
Both devices can provide RSSI functionality, but the AD8307AR is commonly selected for general-purpose RSSI and log-detection applications due to its 500 MHz bandwidth and lower supply current. The AD8306AR is preferable when the design also requires a limiter output for demodulation, since it integrates both RSSI and limiting functions in a single package.