Part A
AD8302ARUZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4149 PCS
- Package
- TSSOP-14
- Series
- RF Detectors
Replacement verdict
Not a drop-in replacement
The AD8304ARUZ and AD8302ARUZ are not interchangeable despite sharing the same TSSOP-14 package. The AD8304ARUZ is a single-channel logarithmic detector optimized for fiber-optic photodiode measurement with a 160 dB dynamic range, while the AD8302ARUZ is a dual-channel gain and phase detector intended for RF/IF signal analysis. Their core functions, input architectures, and output signal types differ fundamentally, so substituting one for the other is not feasible without redesigning the surrounding circuit.
Different output type
Different channel function
Different input architecture
Different application domain
Parts at a glance
Part B
AD8304ARUZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2339 PCS
- Package
- TSSOP-14
- Series
- Linear - Amplifiers - Special Purpose
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8304ARUZ | AD8302ARUZ | Why it matters |
|---|---|---|---|
| Function | 160 dB Range Logarithmic Detector / Controller | RF/IF Gain and Phase Detector | These are fundamentally different functions; the AD8304 measures logarithmic signal magnitude, while the AD8302 measures gain (amplitude ratio) and phase difference between two signals, so they are not functionally interchangeable. |
| Frequency Range | DC to 160 MHz (input bandwidth) | DC to 2.7 GHz | The AD8302 supports much higher RF/IF frequencies, making it suitable for RF applications where the AD8304's lower bandwidth would be insufficient. |
| Dynamic Range | 160 dB (logarithmic) | ~60 dB (gain measurement range) | The AD8304 offers a much wider logarithmic detection range, while the AD8302's gain measurement range is narrower but suited to gain/phase comparison tasks. |
| Primary Output | Logarithmic voltage proportional to input signal level | Two outputs: gain (magnitude ratio) and phase difference voltages | The output type determines what the downstream circuitry can measure; the AD8304 provides signal strength, while the AD8302 provides relative gain and phase information. |
| Number of Input Channels | 1 (single-ended input) | 2 (two independent input channels) | The AD8302 requires two inputs to compute gain and phase ratios, whereas the AD8304 operates on a single input signal. |
| Supply Voltage | 3.0 V to 5.5 V | 2.7 V to 5.5 V | Both operate over similar low-voltage supplies, but the slightly wider lower limit of the AD8302 may allow operation in lower-voltage systems. |
| Package | 16-Lead TSSOP | 14-Lead TSSOP | Different pin counts and footprints mean the two parts are not drop-in replacements on a PCB. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Both share the same industrial temperature range, so environmental suitability is equivalent. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8302ARUZ | AD8304ARUZ |
|---|---|---|
| Part Status | Active | Active |
| Frequency | 2.7GHz | - |
| RF Type | General Purpose | - |
| Input Range | -60dBm ~ 0dBm | - |
| Accuracy | ±0.5dB | - |
| Voltage - Supply | 2.7V ~ 5.5V | - |
| Supply Current | 23 mA | - |
| Mounting Type | Surface Mount | Surface Mount |
| Type | - | Logarithmic Converter |
| Applications | - | Fiber Optics |
Frequently asked questions
What are the primary functional differences between the AD8304ARUZ and AD8302ARUZ?
The AD8304ARUZ is a single-channel, 160 dB logarithmic detector/controller optimized for photodiode current measurement, providing a logarithmic voltage output proportional to input current over a wide dynamic range. The AD8302ARUZ is a dual-channel RF/IF gain and phase detector that measures the amplitude ratio and phase difference between two input signals, outputting voltages proportional to gain (or loss) and phase. They serve fundamentally different measurement functions and are not functionally interchangeable.
Do the AD8304ARUZ and AD8302ARUZ share the same package and pinout?
Both devices are offered in a 14-lead TSSOP package (RU suffix), but their pin functions and internal signal paths differ because they perform different functions. Designers must consult each device's respective datasheet pin configuration before layout; the shared package footprint does not imply pin-for-pin compatibility.
What is the input signal range of the AD8304ARUZ compared with the AD8302ARUZ?
The AD8304ARUZ is specified for logarithmic conversion of photodiode currents spanning approximately 160 dB (from sub-nanoamp to millamp levels), making it suited to optical power monitoring. The AD8302ARUZ operates on two RF/IF voltage inputs and measures gain/loss over a specified range (typically ±30 dB) and phase over 0° to 180°, per its datasheet. The input domains (current vs. RF voltage) are not directly comparable.
Can the AD8302ARUZ be used for photodiode power measurement like the AD8304ARUZ?
No. The AD8302ARUZ is a gain and phase detector intended for RF/IF signal comparison between two channels; it is not specified for logarithmic photodiode current measurement. The AD8304ARUZ is the device specifically characterized for wide-dynamic-range photodiode current-to-log-voltage conversion. Substitution would not meet the AD8304's specified logarithmic conformance.
What are the typical applications for each device?
The AD8304ARUZ is typically used in optical power monitoring, fiber-optic receiver RSSI, and photodiode-based absorbance measurements. The AD8302ARUZ is typically used in RF/IF gain and phase measurement, VSWR/return-loss monitoring, and RF power amplifier linearization and control loops. Application suitability should be confirmed against each datasheet's specified operating conditions.
Are the AD8304ARUZ and AD8302ARUZ drop-in replacements for one another?
No. Despite sharing the 14-lead TSSOP package, the two devices have different pin functions, input signal domains, transfer functions, and specified performance parameters. A direct substitution is not supported by the manufacturer; any replacement requires full validation against the target design's requirements and the respective datasheet specifications.
What supply voltage and operating temperature ranges are specified for these devices?
Both the AD8304ARUZ and AD8302ARUZ are specified for a single-supply operation in the 2.7 V to 5.5 V range and for the industrial temperature range of −40°C to +85°C, per their respective datasheets. Designers should verify the exact limits and derating conditions in the latest revision of each datasheet before finalizing a design.