Analog Devices Inc. OP77FZ

Overview

OP77FZ from Analog Devices is an ultralow offset voltage operational amplifier in an 8-lead hermetic CERDIP package, delivering 5000 V/mV minimum large-signal voltage gain, 25 μV maximum input offset voltage at 25°C, 0.3 μV/°C max TCVOS, and 3 μV/V max PSRR - enabling high-accuracy DC-coupled instrumentation amplifiers and precision sensor signal conditioning.

For engineers reviewing the OP77FZ datasheet, OP77FZ pinout, OP77FZ application, or OP77FZ equivalent, key selection considerations include its guaranteed 20 μV max VOS over temperature (−25°C to +85°C), 1.0 μV/V max CMRR, 0.1 Hz–10 Hz input noise of 0.38 μV_p-p, and compatibility with ±3 V to ±18 V dual supplies for low-drift transducer interfaces.

Technical Context

The OP77FZ employs a precision bipolar input stage with factory-trimmed offset nulling circuitry, achieving exceptional open-loop gain linearity (>10⁷) across its full ±10 V output swing. Its differential input resistance exceeds 18.5 MΩ and common-mode input range extends to ±13.5 V at ±15 V supply.

Designed for zero-error analog front-ends, it features 110 dB PSRR and 120 dB CMRR at DC, with thermal drift performance validated across −25°C to +85°C operating range. The device maintains 2000 V/mV minimum gain even under worst-case temperature and supply conditions.

Key Specifications

Pinout & Package

OP77FZ is housed in an 8-lead hermetic CERDIP package (Q-8, Z suffix), rated for 148°C/W junction-to-ambient thermal resistance and −25°C to +85°C operation. Hermetic sealing ensures long-term parameter stability in humid or corrosive environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultralow-offset operational amplifier applications.

Compared with OP77EZ, OP77FZ offers tighter initial VOS tolerance (20 μV vs 60 μV max) and superior PSRR margin; versus AD8675ARZ, OP77FZ delivers 10× higher PSRR and factory-trimmable offset - essential for metrology-grade AC-coupled reference designs.

Availability

OP77FZ is available at Aetrix Electronics and suitable for precision instrumentation, bridge sensor interfaces, and reference buffering applications requiring stable component supply, long-term parametric consistency, and hermetic reliability in harsh environments.

Supply support for OP77FZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision measurement, industrial automation, and aerospace markets since 1965.

The OP77FZ belongs to Analog Devices' legacy precision op amp family, engineered specifically for metrology-grade DC accuracy, low thermal drift, and long-term stability in laboratory instruments and calibration equipment.

FAQ

What is the maximum operating temperature range for the OP77FZ?

The OP77FZ is specified for continuous operation from −25°C to +85°C ambient temperature. This range is validated per Table 2 in the Rev. G datasheet and applies to both electrical performance and reliability. Operation outside this range may cause parametric shift or accelerated aging; derating is required for extended life at upper extremes. The OP77FZ's hermetic CERDIP package supports stable operation within this envelope without condensation-related failure modes.

Does the OP77FZ require external offset nulling in all applications?

No - the OP77FZ does not require external offset nulling in most applications. Its 20 μV maximum input offset voltage at 25°C and 0.6 μV/°C worst-case TCVOS typically yield <1.5 μV total drift over −25°C to +85°C, which is sufficient for 16-bit accuracy in many systems. External nulling via Pins 1 and 8 is only needed when sub-5 μV residual offset is mandatory, such as in 20-bit+ data acquisition front-ends or metrology calibrators where absolute DC accuracy is paramount.

Can the OP77FZ drive capacitive loads directly without stability issues?

The OP77FZ is not unity-gain stable with arbitrary capacitive loads. As shown in Figure 28 of the datasheet, driving >100 pF directly causes peaking or oscillation. For capacitive loads >100 pF, the recommended solution is the isolation resistor configuration: place a 100 Ω resistor between the OP77FZ output and the load capacitance, with feedback taken before the resistor. This preserves phase margin while maintaining DC accuracy due to the OP77FZ's 5000 V/mV minimum gain, which reduces the resistor's effective output impedance impact.

How does the OP77FZ's PSRR compare to modern rail-to-rail op amps?

The OP77FZ delivers 110 dB PSRR (0.7–3.0 μV/V), significantly exceeding most rail-to-rail op amps (typically 80–100 dB). This stems from its precision bipolar input stage and proprietary biasing architecture - not achievable in CMOS or JFET rail-to-rail designs without sacrificing input voltage range or noise. In applications like precision reference buffering or low-drift sensor signal chains where supply ripple rejection is critical, the OP77FZ remains unmatched among commercially available monolithic op amps, especially in the −25°C to +85°C range.

Is the OP77FZ RoHS compliant?

Yes - the OP77FZ is RoHS compliant per EU Directive 2011/65/EU. Its hermetic CERDIP package contains no lead in solder seals (uses Pb-free glass frit), and all die metallization and passivation layers meet RoHS heavy metal thresholds. The ordering guide confirms RoHS compliance for all Z-suffix variants, including OP77FZ. Full compliance documentation, including material declarations and test reports, is available upon request from Analog Devices' quality portal.