Part A
AD8331ARQZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 3550 PCS
- Package
- QSOP-20
- Series
- Amplificateur linéaire - spécial
Replacement verdict
Compatible functional replacement candidate
The AD8331ARQZ and AD8330ARQZ-RL are both variable gain amplifiers from Analog Devices in the same 16-lead QSOP package, sharing a closely related core architecture and supply requirements. However, they differ in signal-path configuration, gain-control interface, and bandwidth, so the AD8330ARQZ-RL can serve as a functional substitute only after the system's gain range, control method, and frequency response are validated against the target design.
Package Type
High match
Supply Voltage Range
High match
Gain Control Interface
Validation required
Bandwidth and Gain Range
Not compatible
Parts at a glance
Part B
AD8330ARQZ-RL
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 5013 PCS
- Package
- SSOP-16
- Series
- Amplificateurs linéaires - instruments, amplificateurs opérationnels, amplificateurs tampons
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8331ARQZ | AD8330ARQZ-RL | Why it matters |
|---|---|---|---|
| Function Type | Variable Gain Amplifier (VGA) with LNA and VGA channels | Variable Gain Amplifier (VGA) | The AD8331 integrates a low-noise preamplifier (LNA) plus VGA, while the AD8330 is a standalone VGA; this affects whether an external LNA is needed in the signal chain. |
| Gain Range | -4.5 dB to +43.5 dB (VGA); LNA adds ~19 dB | 0 dB to +50 dB | Different gain spans determine the dynamic range and input signal levels each device can accommodate in an application. |
| -3 dB Bandwidth | 120 MHz | 150 MHz | Bandwidth sets the maximum signal frequency the amplifier can process with acceptable gain flatness. |
| Input Noise (Voltage Noise Density) | 0.74 nV/√Hz (LNA input) | 5 nV/√Hz | Lower input noise improves sensitivity in low-level signal applications such as ultrasound and medical imaging. |
| Supply Voltage | 5 V single supply | 2.7 V to 6 V single supply | Supply range affects compatibility with system power rails and low-power design flexibility. |
| Supply Current | ~58 mA | ~20 mA | Quiescent current impacts power budget and thermal considerations in portable or dense systems. |
| Output Voltage Swing / Output Drive | Differential output, ~2 V p-p | Differential output, ~2 V p-p | Output swing determines the maximum signal amplitude deliverable to the ADC or next stage. |
| Package | 20-Lead QSOP | 16-Lead QSOP | Package footprint and pin count affect PCB layout and drop-in substitutability. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Industrial temperature range ensures reliable operation across harsh environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8331ARQZ | AD8330ARQZ-RL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Part Status | Active | Active |
| Amplifier Type | - | Variable Gain |
| Number of Circuits | - | 1 |
| Output Type | - | Differential, Rail-to-Rail |
| Slew Rate | - | 1500V/µs |
| -3 dB Bandwidth | - | 150 MHz |
| Current - Input Bias | - | 100 nA |
| Supply Current | - | 20mA |
| Voltage - Supply Span(Min) | - | 2.7 V |
| Voltage - Supply Span(Max) | - | 6 V |
| Operating Temperature | - | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Series | X-AMP® | - |
| Type | Variable Gain Amplifier | - |
| Applications | Signal Processing | - |
Frequently asked questions
What are the primary functional differences between the AD8331ARQZ and AD8330ARQZ-RL?
The AD8331ARQZ is a single-channel, ultralow noise variable gain amplifier (VGA) with a built-in low noise preamplifier (LNP) and programmable gain range, optimized for ultrasound and imaging applications. The AD8330ARQZ-RL is a wideband, dc-to-150 MHz VGA with a linear-in-dB gain control interface, offering a different gain range and input architecture. They are not functionally equivalent and serve different signal-chain roles.
Are the AD8331ARQZ and AD8330ARQZ-RL pin-compatible and directly interchangeable?
No. Although both are offered in a 16-lead QSOP (RQ-16) package, their pin functions and internal architectures differ. The AD8331ARQZ integrates an LNP with active termination and a VGA, while the AD8330ARQZ-RL provides a different input/output structure and gain-control scheme. Direct substitution without redesign and validation is not supported.
What are the gain control characteristics of each device?
The AD8331ARQZ provides a programmable gain range with a linear-in-dB control interface and an integrated preamplifier, with gain controlled via the GAIN pin voltage. The AD8330ARQZ-RL offers a linear-in-dB gain control over a wide range using the VDBS pin, with a nominal gain slope specified in its datasheet. Exact gain ranges and slopes should be confirmed against the respective Analog Devices datasheets.
Which device is better suited for ultrasound receive chains?
The AD8331ARQZ is specifically designed for ultrasound and imaging receive paths, featuring an ultralow noise preamplifier, active input termination, and a VGA optimized for time-gain compensation. The AD8330ARQZ-RL is a general-purpose wideband VGA and is not positioned as an ultrasound front-end device. Selection should be based on the application's noise, bandwidth, and gain-control requirements.
How do the bandwidth and noise specifications compare?
The AD8330ARQZ-RL is specified for wideband operation up to approximately 150 MHz, making it suitable for high-frequency signal processing. The AD8331ARQZ is optimized for lower-frequency ultrasound bands with an emphasis on ultralow input-referred noise from its integrated LNP. Designers must consult the respective datasheets for exact bandwidth and noise figures, as these parameters are application- and gain-dependent.
What does the "-RL" suffix indicate on the AD8330ARQZ-RL?
The "-RL" suffix denotes a tape-and-reel packaging option from Analog Devices, indicating the device is supplied in reels for automated assembly. It does not indicate a different silicon die or performance grade compared to the base AD8330ARQZ part number. The AD8331ARQZ is likewise available in standard packaging options; confirm ordering codes with the manufacturer or authorized distributor.
Can both devices operate from the same supply voltage?
Both the AD8331ARQZ and AD8330ARQZ-RL are designed for single-supply operation in the 2.7 V to 5.5 V range, with typical operation at 5 V. However, supply current, output swing, and biasing requirements differ between the two architectures. Verify the exact supply and decoupling requirements in each device's datasheet before finalizing a design.