Analog Devices Inc./Maxim Integrated MAX1673ESA+T

Overview

MAX1673ESA+T 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 - used in analog signal-processing circuits requiring low-noise bias rails.

For engineers reviewing the MAX1673ESA+T datasheet, MAX1673ESA+T pinout, MAX1673ESA+T application, or MAX1673ESA+T equivalent, key selection criteria include regulated negative output capability, dual regulation modes (Skip vs. Linear), shutdown control, SO-8 package compatibility, and capacitor-based design simplicity for space-constrained systems.

Technical Context

The MAX1673ESA+T implements On-Demand™ regulation via two distinct internal control schemes: in Skip mode, it dynamically adjusts switching frequency (205–515kHz) based on load to minimize quiescent current; in Linear mode, it maintains constant 350kHz operation while modulating switch resistance to regulate output voltage.

Its feedback loop references FB to 0V (±25mV threshold), enabling precise output setting from –1.5V to –VIN (Linear) or 0V to –VIN (Skip) using external R1/R2 dividers; shutdown mode pulls OUT to GND through a 1Ω internal switch and draws only 0.1–1µA supply current.

Key Specifications

Pinout & Package

MAX1673ESA+T is housed in an 8-pin SO (Small Outline) package with exposed pad not present; footprint matches JEDEC MS-012AC standard, suitable for automated SMT assembly and thermal management via PCB copper pour under the body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX868ESA+ and TPS60403DBVR, the MAX1673ESA+T uniquely supports both high-current delivery (125mA) and user-selectable regulation modes - making it the only option among the three capable of balancing low-noise performance and ultra-low quiescent current in the same design.

Availability

MAX1673ESA+T is available at Aetrix Electronics and suitable for hard disk drives, portable measurement instruments, digital cameras, modems, and analog signal-processing systems requiring stable component supply across industrial temperature ranges (–40°C to +85°C).

Supply support for MAX1673ESA+T 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+T belongs to Maxim's regulated charge-pump DC-DC converter product line, designed specifically for compact, inductorless negative rail generation in space- and power-sensitive analog systems.

FAQ

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

The MAX1673ESA+T delivers up to 125mA of continuous regulated negative output current under typical conditions (VIN = 5V, TA = +25°C). Absolute maximum rating allows 135mA, but sustained operation above 125mA may exceed thermal limits depending on PCB layout and ambient temperature. The MAX1673ESA+T achieves this without inductors, using only ceramic capacitors and resistors.

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

The LIN/SKIP pin selects between two internal regulation schemes: connecting it to IN enables Linear mode (fixed 350kHz switching with variable switch resistance), while grounding it activates Skip mode (variable-frequency operation that skips cycles to maintain regulation). This choice directly impacts output ripple, quiescent current, and EMI profile - the MAX1673ESA+T must be configured at power-up and cannot change modes dynamically during operation.

Can the MAX1673ESA+T generate a –5V output from a 5V input?

No - the MAX1673ESA+T regulates output to a maximum magnitude of –VIN, meaning its most negative output is –5V only if VIN is ≥5V and the device is configured in Skip mode (which allows 0V to –VIN). However, in Linear mode, minimum output is –1.5V, so –5V is unattainable. For –5V generation from 5V, external resistor scaling or a different topology is required; the MAX1673ESA+T cannot invert beyond its input voltage magnitude.

What is the shutdown behavior of the MAX1673ESA+T, and how does it affect the output node?

When SHDN is driven low, the MAX1673ESA+T halts all internal switching and activates an internal ~1Ω NMOS switch between OUT and GND. This actively discharges the output capacitor and holds OUT near ground potential, drawing only 0.1–1µA supply current. Unlike passive leakage paths, this controlled discharge prevents floating outputs and eliminates need for external pull-down components in bias-rail applications using the MAX1673ESA+T.

What capacitor types and values are recommended for stable operation of the MAX1673ESA+T?

Maxim recommends X7R ceramic capacitors: 2.2µF for CFLY (flying capacitor), 22µF for COUT (output), and 10µF for CIN (input). Ceramic dielectrics minimize ESR and size; tantalum alternatives increase ripple and require derating. In Linear mode, COUT must have ≤100mΩ ESR for stability; in Skip mode, ripple is dominated by CFLY/COUT charge transfer, so larger COUT values (e.g., 47µF) further reduce peak-to-peak variation. All capacitors should be placed close to the MAX1673ESA+T pins.