Analog Devices Inc./Maxim Integrated MAX1673ESA+

Overview

MAX1673ESA+ from Maxim Integrated is a regulated charge-pump DC-DC inverter IC that generates a stable negative output voltage (up to –1 × VIN) from a 2V–5.5V positive input, delivering up to 125mA output current with 35µA quiescent supply current in Skip mode and fixed 350kHz switching in Linear mode. It operates across –40°C to +85°C and is used in analog signal-processing circuits requiring low-noise or ultra-low-power negative bias rails.

For engineers reviewing the MAX1673ESA+ datasheet, MAX1673ESA+ pinout, MAX1673ESA+ application, or MAX1673ESA+ equivalent, key selection criteria include regulated negative output capability, dual regulation modes (Skip vs. Linear), shutdown control, FB-based output voltage programming, and SO-8 package compatibility for space-constrained embedded power designs.

Technical Context

The MAX1673ESA+ implements a two-phase switched-capacitor inverter topology with internal MOSFET switches (S1–S4) and On-Demand™ regulation logic. In Skip mode, it dynamically adjusts switching frequency (35kHz–350kHz) based on load to minimize quiescent current; in Linear mode, it maintains constant 350kHz operation while modulating switch resistance for ripple-sensitive applications.

Regulation is achieved via feedback at the FB pin, which servo-controls to 0V (±25mV threshold), enabling precise output voltage setting using external R1/R2 dividers. The device integrates a 1Ω internal pull-down on OUT during shutdown and supports logic-level SHDN control with 0.3×VIN/0.7×VIN thresholds.

Key Specifications

Pinout & Package

MAX1673ESA+ is housed in an 8-pin SO (Small Outline) package with standard JEDEC MS-012AC dimensions (4.9mm × 6.0mm, 1.27mm pitch). All pins are surface-mount, lead-free, and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar charge-pump inverter applications.

Compared with MAX1673ESA+, MAX1674ESA+ offers higher current and broader input range in identical packaging, while TPS60403DBVR trades output capability for smaller size and higher switching frequency-making MAX1673ESA+ optimal for balanced 125mA/low-noise/low-IQ requirements in SO-8 layouts.

Availability

MAX1673ESA+ is available at Aetrix Electronics and suitable for hard disk drives, measurement instruments, camcorders, and analog signal-processing systems requiring stable component supply, long-lifecycle availability, and guaranteed industrial-temperature operation.

Supply support for MAX1673ESA+ 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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX1673ESA+ belongs to Maxim's regulated charge-pump inverter product line, designed specifically for compact, inductorless negative voltage generation in space- and power-constrained analog subsystems.

FAQ

What is the maximum output current specification for the MAX1673ESA+?

The MAX1673ESA+ delivers up to 125mA of continuous regulated negative output current under typical operating conditions (VIN = 5V, TA = +25°C). Absolute maximum rating is 135mA, but sustained operation above 125mA may exceed thermal limits depending on PCB layout and ambient temperature. The MAX1673ESA+ datasheet specifies 125mA as the guaranteed minimum output current across –40°C to +85°C with proper capacitor selection and thermal management.

How does the LIN/SKIP pin affect regulation behavior in the MAX1673ESA+?

The LIN/SKIP pin on the MAX1673ESA+ selects between two distinct regulation schemes: driving it high (≥0.7×VIN) enables Linear mode with fixed 350kHz switching and variable switch resistance for low-noise output; driving it low (≤0.3×VIN) activates Skip mode, where the MAX1673ESA+ skips pulses to maintain regulation, reducing quiescent current to 35µA at light loads. This pin directly determines ripple profile, efficiency, and IQ - no external configuration registers or I²C commands are involved.

Can the MAX1673ESA+ generate a –3.3V output from a 3.3V input?

Yes, the MAX1673ESA+ can generate –3.3V from a 3.3V input in Skip mode, where output is adjustable from 0V to –VIN. Using R1 = 100kΩ and R2 = 60.4kΩ yields VOUT ≈ –3.02V (per datasheet Figure 1), and fine-tuning R2 achieves exact –3.3V. In Linear mode, minimum output is –1.5V, so –3.3V is only achievable in Skip mode. The MAX1673ESA+ FB pin servoing to 0V ±25mV ensures stable regulation across load and temperature.

What is the shutdown behavior of the MAX1673ESA+?

When SHDN is driven low, the MAX1673ESA+ halts all switching activity and activates an internal ~1Ω switch connecting OUT to GND, discharging the output capacitor and ensuring rapid, controlled rail collapse. Shutdown current drops to 1µA, and the device remains in this state until SHDN rises above 0.7×VIN. This behavior is explicitly characterized in the MAX1673ESA+ datasheet under "Shutdown Mode" and "Electrical Characteristics" tables, confirming safe, repeatable power sequencing.

Which external capacitors are required for stable operation of the MAX1673ESA+?

The MAX1673ESA+ requires three external capacitors: a 10µF input capacitor (CIN), a 22µF output capacitor (COUT), and a 2.2µF flying capacitor (CFLY), all recommended as X7R ceramic types for low ESR and stable temperature performance. COUT must be ≥10× CFLY for optimal ripple suppression; using 47µF further reduces ripple in Skip mode. These values are validated in the MAX1673ESA+ Typical Operating Characteristics plots and Application Information section.