Part A
AD8304ARU
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2030 PCS
- Series
- Linear - Amplifiers - Special Purpose Amplifiers
Replacement verdict
Not a drop-in replacement
The AD8302ARUZ and AD8304ARU are not drop-in replacements for one another. Although both are analog logarithmic/RF signal-processing ICs from Analog Devices in similar TSSOP-style packages, they serve fundamentally different functions: the AD8302ARUZ is a dual-channel RF gain/phase detector, while the AD8304ARU is a single-channel logarithmic converter optimized for photodiode current measurement. Their input signal domains, output types, channel counts, and core application roles differ, so substituting one for the other requires full electrical and functional validation.
Different output type
Different channel count
Different input signal domain
Different application function
Parts at a glance
Part B
AD8302ARUZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4149 PCS
- Package
- TSSOP-14
- Series
- RF Detectors
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8302ARUZ | AD8304ARU | Why it matters |
|---|---|---|---|
| Function | RF/IF gain and phase detector | Logarithmic amplifier (log amp) detector | The core function differs: one measures gain/phase between two signals, the other converts signal amplitude to a logarithmic output, so they are not direct substitutes. |
| Frequency Range | LF to 2.7 GHz | DC to 160 MHz (typical) | Operating frequency range determines whether the part suits the target signal band; the AD8302 covers much higher RF frequencies. |
| Primary Output | Gain (voltage) and phase (voltage) outputs | Logarithmic voltage output proportional to input amplitude | Output type dictates the downstream signal processing; gain/phase vs. log-amplitude outputs serve different measurement architectures. |
| Dynamic Range | ~60 dB (gain measurement) | ~80 dB (logarithmic) | Dynamic range defines the span of signal levels the detector can accurately measure; the log amp offers wider amplitude range. |
| Supply Voltage | 2.7 V to 5.5 V | 3.0 V to 5.5 V | Supply range affects compatibility with the system power rail; slight differences may matter in low-voltage designs. |
| Package | 16-lead TSSOP | 14-lead TSSOP | Different pin counts and footprints prevent drop-in board replacement without layout changes. |
| Number of Input Channels | Two (dual-input for gain/phase comparison) | One (single-ended input) | Channel count determines whether the device can compare two signals or only measure a single signal's amplitude. |
| Typical Application | RF power amplifier gain/phase monitoring, VSWR measurement | Optical/RF signal strength indication (RSSI), AGC | Intended applications reflect the internal architecture and guide whether the part fits the measurement task. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8304ARU | AD8302ARUZ |
|---|---|---|
| Part Status | Obsolete | Active |
| Base Product Number | AD8304 | - |
| Type | Logarithmic Converter | - |
| Applications | Fiber Optics | - |
| Mounting Type | Surface Mount | Surface Mount |
| Packaging | Tube | - |
| Frequency | - | 2.7GHz |
| RF Type | - | General Purpose |
| Input Range | - | -60dBm ~ 0dBm |
| Accuracy | - | ±0.5dB |
| Voltage - Supply | - | 2.7V ~ 5.5V |
| Supply Current | - | 23 mA |
Frequently asked questions
What are the primary functions of the AD8302ARUZ and AD8304ARU?
The AD8302ARUZ is a fully integrated RF/IF gain and phase detector that measures amplitude and phase differences between two input signals up to 2.7 GHz. The AD8304ARU is a logarithmic amplifier (log amp) designed for optical power measurement, providing a linear-in-dB output over a 160 dB dynamic range for photodiode current.
Are the AD8302ARUZ and AD8304ARU pin-compatible or functionally interchangeable?
No. Although both are offered in a 14-lead TSSOP package (RU suffix), they are functionally different devices. The AD8302ARUZ is a gain/phase detector with two signal inputs and two outputs (VMAG and VPHS), while the AD8304ARU is a log amplifier with a photodiode input and a single VLOG output. They cannot be substituted for one another in a design.
What is the specified frequency range of the AD8302ARUZ?
Per the Analog Devices datasheet, the AD8302ARUZ operates from low frequency up to 2.7 GHz, with specified performance over a 0 Hz to 2.7 GHz range for gain and phase measurement.
What dynamic range does the AD8304ARU provide?
The AD8304ARU provides a 160 dB logarithmic dynamic range (typically specified for input currents from 100 pA to 10 mA), making it suitable for optical power monitoring in fiber-optic receivers.
What supply voltage do the AD8302ARUZ and AD8304ARU require?
Both devices operate from a single supply of 3.0 V to 5.5 V, as specified in their respective Analog Devices datasheets.
What are the typical applications for each device?
The AD8302ARUZ is used in RF/IF power amplifier linearization, gain and phase measurement, and VSWR detection. The AD8304ARU is used in optical power measurement, fiber-optic receiver RSSI, and photodiode signal conditioning.
What package do the AD8302ARUZ and AD8304ARU use?
Both devices are supplied in a 14-lead TSSOP package, indicated by the "RU" suffix in the part number (AD8302ARUZ and AD8304ARU). The "Z" suffix on the AD8302ARUZ denotes RoHS-compliant lead-free construction.