Part A
AD8608ARUZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3744 PCS
- Package
- TSSOP-14
- Series
- Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8608ARUZ and AD8604DRU are both quad-channel CMOS operational amplifiers from Analog Devices with comparable supply voltage ranges and rail-to-rail input/output behavior, making them a viable functional replacement candidate in many designs. However, the AD8608ARUZ offers lower input offset voltage and lower noise, while the AD8604DRU provides higher output current capability and a different package footprint, so engineers should validate application-specific requirements before substituting one for the other.
Amplifier Channel Count
High match
Supply Voltage Range
High match
Input Offset Voltage
Validation required
Package Type
Validation required
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8608ARUZ | AD8604DRU | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 4 | 4 | Both are quad op-amps, so channel count matches for multi-channel signal chains. |
| Input Offset Voltage (max) | 65 µV | 750 µV | Lower offset improves DC accuracy; AD8608 is significantly more precise than AD8604. |
| Input Bias Current (typ) | 0.2 pA | 0.2 pA | Ultra-low CMOS input bias current suits high-impedance sensor and photodiode interfaces. |
| Gain Bandwidth Product | 10 MHz | 8.4 MHz | Higher GBW allows wider closed-loop bandwidth and faster settling in signal conditioning. |
| Slew Rate | 5 V/µs | 6 V/µs | Slew rate limits large-signal response; AD8604 is slightly faster for fast transients. |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Identical single-supply range enables drop-in use in 3 V and 5 V systems. |
| Supply Current per Amplifier (typ) | 1.2 mA | 1.2 mA | Quiescent current affects power budget in portable and battery-powered designs. |
| Input Noise Voltage Density | 8 nV/√Hz | 33 nV/√Hz | Lower noise density gives better SNR; AD8608 is preferable for low-level signal amplification. |
| Package | 14-Lead TSSOP | 14-Lead TSSOP | Same package footprint allows direct PCB replacement without layout changes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +85 °C | Wider temperature range of AD8608 suits harsher industrial environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8608ARUZ | AD8604DRU |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Series | DigiTrim® | DigiTrim® |
| Part Status | Active | Obsolete |
| Amplifier Type | CMOS | CMOS |
| Number of Circuits | 4 | 4 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 5V/µs | 6V/µs |
| Gain Bandwidth Product | 10 MHz | 8.4 MHz |
| Current - Input Bias | 1 pA | 0.2 pA |
| Voltage - Input Offset | 80 µV | 1.3 mV |
| Supply Current | 1mA (x4 Channels) | 750µA (x4 Channels) |
| Current - Output / Channel | 80 mA | 50 mA |
| Voltage - Supply Span(Min) | 2.7 V | 2.7 V |
| Voltage - Supply Span(Max) | 5.5 V | 5.5 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the AD8608ARUZ and AD8604DRU?
The AD8608ARUZ is a quad, low-noise, CMOS rail-to-rail input/output operational amplifier specified for operation from 2.7 V to 5.5 V, supplied in a 14-lead TSSOP (RU-14) package. The AD8604DRU is also a quad, rail-to-rail input/output CMOS amplifier from the same AD8604 family, supplied in a 14-lead TSSOP (RU-14) package. Both share the same quad topology and TSSOP-14 footprint, but they differ in their specified noise, bandwidth, and supply-current performance per the respective datasheets, so the exact grade must be confirmed against the manufacturer data before substitution.
Are the AD8608ARUZ and AD8604DRU pin-compatible?
Yes. Both devices are quad operational amplifiers offered in the 14-lead TSSOP (RU-14) package, and the AD8604 family pinout assigns the same functions to the 14 TSSOP pins (four amplifier inputs/outputs plus V+ and V−). Pin-for-pin compatibility in the same package should still be verified against the specific datasheet revision before layout reuse.
What supply voltage range do these amplifiers support?
Both the AD8608ARUZ and AD8604DRU are specified for single-supply operation from 2.7 V to 5.5 V, and they also operate from dual supplies within that total range. Designs should confirm the exact specified limits in the manufacturer datasheet for the grade being used.
Do the AD8608ARUZ and AD8604DRU have rail-to-rail input and output?
Yes. Both are CMOS rail-to-rail input/output amplifiers, allowing input signals to swing to the supply rails and output swing close to both rails. This makes them suitable for low-voltage single-supply signal conditioning where headroom is limited.
Can the AD8608ARUZ be used as a direct drop-in replacement for the AD8604DRU?
Package and pinout compatibility in the TSSOP-14 footprint supports a physical drop-in, but electrical equivalence must be confirmed. The two parts differ in specified noise, gain bandwidth, and quiescent current per their datasheets, so a substitution should be validated against the target design's accuracy, bandwidth, and power budget before release.
What are typical applications for these quad CMOS amplifiers?
Because both are low-voltage, rail-to-rail input/output quad amplifiers, they are commonly used in portable instrumentation, sensor signal conditioning, active filters, photodiode amplification, and ADC driver stages where multiple channels and low supply voltage are required. Final selection between the two should be based on the noise and bandwidth specifications in the respective datasheets.
How should I decide between the AD8608ARUZ and AD8604DRU for a new design?
Compare the datasheet parameters that matter for the application: input voltage noise density, gain bandwidth product, slew rate, input offset voltage, and quiescent current per amplifier. Select the grade whose verified specifications meet the design margins, and confirm package, temperature range, and supply limits against the manufacturer datasheet before committing to a bill of materials.