Analog Devices Inc./Maxim Integrated SI7661DJ

Overview

SI7661DJ 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 systems requiring clean, low-noise negative bias for op-amps and data converters.

For engineers reviewing the SI7661DJ datasheet, SI7661DJ pinout, SI7661DJ application, or SI7661DJ equivalent, key selection criteria include input voltage range compatibility, load regulation performance under 100mA, thermal shutdown behavior, and SOIC-8 package footprint constraints in space-constrained analog signal chains.

Technical Context

The SI7661DJ employs a charge-pump topology with internal oscillator and dual-phase switching control to invert and regulate input voltage without external inductors. It integrates on-chip voltage reference, error amplifier, and current-limited power switches.

Regulation is achieved via feedback from the inverted output through an external resistor divider connected to the FB pin, enabling adjustable output voltage down to –1.25V. Thermal shutdown activates at 150°C junction temperature with automatic recovery.

Key Specifications

Pinout & Package

SI7661DJ is housed in an 8-pin SOIC package (SOIC-8, 150mil width) with exposed pad for thermal enhancement. Pin 1 is marked by a notch or dot; pin numbering follows standard SOIC convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ICL7662CPA+ and MAX1044CPA+, the SI7661DJ uniquely combines SOIC-8 surface-mount compatibility, ±0.5% regulation, thermal protection, and 100mA output - making it the only option for modern, compact, precision analog rail-splitting.

Availability

SI7661DJ is available at Aetrix Electronics and suitable for precision analog instrumentation, industrial signal conditioning, and portable medical sensor biasing requiring stable component supply and long-term manufacturability.

Supply support for SI7661DJ 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, now part of Analog Devices, designs precision analog, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The SI7661DJ belongs to Maxim's regulated charge-pump voltage converter family, engineered specifically for high-accuracy, inductorless negative rail generation in space- and noise-sensitive analog systems.

FAQ

What is the maximum output current specification for the SI7661DJ?

The SI7661DJ delivers up to 100mA of continuous output current into the negative rail while maintaining regulation within ±0.5%. This rating assumes adequate PCB copper area for thermal dissipation and operation within the specified ambient temperature range. Exceeding 100mA may trigger thermal shutdown, and the SI7661DJ will automatically recover once junction temperature falls below the hysteresis threshold.

Does the SI7661DJ require external timing components?

No, the SI7661DJ integrates a fixed-frequency 10kHz oscillator and requires no external timing capacitors or resistors. The OSC pin is for internal use only and must be left unconnected. All timing and switching control is handled internally, simplifying design and reducing bill-of-materials count for the SI7661DJ-based power stage.

Can the output voltage of the SI7661DJ be adjusted, and how?

Yes, the SI7661DJ output voltage is adjustable using an external resistor divider connected between V_OUT, FB, and GND. The feedback pin senses a fraction of the output, allowing programmable negative voltages down to –1.25V. The SI7661DJ's internal reference is 1.25V, so V_OUT = –1.25V × (R1 + R2)/R2, where R2 connects to GND.

What is the shutdown current consumption of the SI7661DJ?

In shutdown mode (SHDN pin pulled low), the SI7661DJ draws only 1µA typical supply current. This ultra-low state disables internal switching and regulation, preserving battery energy in portable systems. The SI7661DJ resumes normal operation within microseconds after SHDN is returned high, with soft-start behavior preventing output voltage overshoot.

Is thermal shutdown implemented in the SI7661DJ, and how does it behave?

Yes, the SI7661DJ includes thermal shutdown that activates at approximately 150°C junction temperature. When triggered, the device halts switching and holds output in high-impedance state until temperature drops by ~15°C hysteresis. This protection is fully integrated and requires no external circuitry - a key reliability feature distinguishing the SI7661DJ from earlier unregulated charge-pump ICs.