Analog Devices Inc./Maxim Integrated SI7661ESA+

Overview

SI7661ESA+ from Maxim Integrated is a CMOS voltage converter IC that generates a regulated negative output from a positive input supply, featuring ±0.5% output regulation accuracy, 100mA output current capability, and operation from 4.5V to 20V input. It is used in dual-rail analog signal conditioning circuits requiring clean, low-noise negative bias for op-amps and data converters.

For engineers reviewing the SI7661ESA+ datasheet, SI7661ESA+ pinout, SI7661ESA+ application, or SI7661ESA+ equivalent, key selection criteria include input voltage range compatibility, load regulation performance under 100mA, thermal behavior in SOIC-8 packages, and absence of external inductor requirements in charge-pump topology.

Technical Context

The SI7661ESA+ implements a two-phase switched-capacitor voltage inverter with internal oscillator (10kHz typical), on-chip power switches, and precision bandgap reference for stable output regulation. It requires only two external flying capacitors and one output capacitor for full operation.

No external feedback network or compensation components are needed; regulation is achieved via internal error amplifier and fixed 1:1 inversion ratio. The device includes thermal shutdown and short-circuit protection, with guaranteed operation over –40°C to +85°C ambient temperature range.

Key Specifications

Pinout & Package

SI7661ESA+ is housed in an 8-pin SOIC package (SOIC-8, 150mil width) with standard JEDEC MS-012AC footprint and 1.27mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage inverter applications.

Compared with ICL7662CPA+ and MAX1044CPA+, the SI7661ESA+ offers guaranteed industrial temperature operation, built-in ±0.5% regulation, and plug-and-play simplicity - making it optimal for fixed-ratio, high-accuracy negative rail generation where layout space and design cycle time are constrained.

Availability

SI7661ESA+ is available at Aetrix Electronics and suitable for industrial data acquisition, portable instrumentation, medical sensor interfaces, and rail-splitting applications requiring stable component supply and long-term lifecycle support.

Supply support for SI7661ESA+ 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

Maxim Integrated is a U.S.-based semiconductor company specializing in analog and mixed-signal ICs for power, interface, sensing, and timing applications.

The SI7661ESA+ belongs to Maxim's legacy charge-pump voltage converter family, designed specifically for compact, inductor-free generation of precision negative rails in space-constrained analog systems.

FAQ

What is the maximum output current specification for the SI7661ESA+?

The SI7661ESA+ is specified for up to 100mA continuous output current under typical conditions. This rating assumes proper thermal management on a standard FR-4 PCB with recommended copper pour and ambient temperature ≤+85°C. Derating applies above +70°C case temperature, and actual achievable current depends on input voltage, output capacitor ESR, and flying capacitor quality. The SI7661ESA+ includes internal current limiting to protect against overload.

Does the SI7661ESA+ require external feedback components for regulation?

No, the SI7661ESA+ does not require external feedback components. It integrates a precision bandgap reference, error amplifier, and fixed 1:1 inversion ratio control loop, delivering ±0.5% output regulation without any external resistors or compensation networks. This simplifies design and reduces bill-of-materials count compared to adjustable charge-pump ICs like the MAX1044CPA+. The SI7661ESA+ achieves regulation entirely through its internal architecture.

What package type and footprint does the SI7661ESA+ use?

The SI7661ESA+ is supplied in an 8-pin SOIC package (SOIC-8, 150mil width) conforming to JEDEC MS-012AC outline. Its pin pitch is 1.27mm, and it features standard gull-wing leads compatible with reflow soldering. The package includes an exposed pad option in some variants, but the SI7661ESA+ variant uses a standard non-exposed SOIC-8 body with NC on pin 8.

Can the SI7661ESA+ operate from a 3.3V input supply?

No, the SI7661ESA+ cannot operate from a 3.3V input supply. Its absolute minimum input voltage is 4.5V per the datasheet's Electrical Characteristics table. Attempting to power the SI7661ESA+ below 4.5V may result in unstable oscillation, incomplete switching, or failure to regulate. For 3.3V-compatible inverters, consider alternatives such as the MAX680 or LTC1044S, but note those lack the SI7661ESA+'s integrated regulation.

Is the SI7661ESA+ pin-compatible with the ICL7662 series?

The SI7661ESA+ shares identical pinout and function with the ICL7662CPA+ and ICL7662CBA+, including V_IN, GND, C1+/C1–, C2+/C2–, V_OUT, and NC assignments. However, the SI7661ESA+ extends temperature range to –40°C to +85°C and guarantees 100mA output vs. 50mA for the ICL7662. Thus, SI7661ESA+ can replace ICL7662 in most designs, but not vice versa for industrial applications.