Analog Devices Inc./Maxim Integrated MAX860EUA+

Overview

MAX860EUA+ from Maxim Integrated is a frequency-selectable, 50mA switched-capacitor voltage converter that inverts +1.5V to +5.5V inputs or doubles +2.5V to +5.5V inputs. It operates at selectable switching frequencies of 6kHz, 50kHz, or 130kHz, delivers 87% efficiency at 50mA load, and features 200µA quiescent current and 1µA shutdown current. It is used in portable medical instruments requiring compact, inductorless negative rail generation.

For engineers reviewing the MAX860EUA+ datasheet, MAX860EUA+ pinout, MAX860EUA+ application, or MAX860EUA+ equivalent, key selection considerations include its three-frequency control (FC pin), low-noise inverter/doubler dual-mode operation, 12Ω output resistance, µMAX-8 package compatibility, and direct replacement path for ICL7660/MAX660 designs with minimal board changes.

Technical Context

The MAX860EUA+ implements a BiCMOS charge-pump architecture with internal flying-capacitor switching controlled by an oscillator whose frequency is set via the FC pin (VDD, GND, or OUT). It supports two operating modes: inverter (LV = GND) producing –VIN, and doubler (LV = OUT) producing +2VIN - each with distinct input voltage ranges and identical 50mA output capability.

Its shutdown function is active-low on pin 7 (–S-H-D-N–), reducing supply current to <1µA; output regulation is unregulated but load-stable due to 12Ω typical output resistance. The device uses no inductors and relies on external low-ESR capacitors (C1, C2) whose values directly impact ripple, output resistance, and maximum deliverable current per frequency mode.

Key Specifications

Pinout & Package

MAX860EUA+ is housed in an 8-pin µMAX® package (U8-1 outline, 3mm × 3mm, 1.11mm height), RoHS-compliant, with exposed pad for thermal enhancement. Pin 1 is FC; pin 8 is VDD. The package is pin-compatible with SO-8 variants but requires µMAX-specific PCB footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switched-capacitor voltage converter applications.

Compared with MAX660CPA+, MAX860EUA+ trades 50mA output and frequency flexibility for smaller size and lower quiescent current; compared with ICL7660ACPA+, it delivers 5× more current, 4.6× lower output resistance, and programmable noise spectrum - making it suitable for modern portable instrumentation where performance and layout density are critical.

Availability

MAX860EUA+ is available at Aetrix Electronics and suitable for portable medical sensors, handheld test equipment, interface power supplies, and operational-amplifier power rails requiring stable component supply across industrial temperature ranges (–40°C to +85°C).

Supply support for MAX860EUA+ 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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX860/MAX861 product line was designed specifically to replace aging ICL7660-based designs with higher efficiency, greater output current, and frequency-selectable operation - targeting space- and power-constrained portable electronics.

FAQ

What is the maximum output current of the MAX860EUA+?

The MAX860EUA+ delivers up to 50mA continuous output current in both inverter and doubler configurations. This rating assumes proper capacitor selection (e.g., 10µF low-ESR ceramics), ambient temperature ≤+85°C, and adequate PCB copper area for thermal dissipation. Exceeding 50mA may cause excessive output droop or thermal shutdown in sustained operation.

How do I configure the MAX860EUA+ for voltage inversion versus doubling?

Configure the MAX860EUA+ for inversion by connecting the LV pin to GND; for doubling, connect LV to the OUT pin. These connections determine internal switch routing and define the input voltage range: inversion accepts +1.5V to +5.5V, while doubling requires +2.5V to +5.5V. Do not float LV unless operating above 3V in inverter mode.

What are the three switching frequencies of the MAX860EUA+ and how are they selected?

The MAX860EUA+ offers 6kHz (FC = VDD or open), 50kHz (FC = GND), and 130kHz (FC = OUT). These frequencies directly affect capacitor sizing and quiescent current: higher frequencies allow smaller C1/C2 but increase supply current, while lower frequencies reduce IDD but require larger capacitors to maintain output stability and ripple performance.

Can the MAX860EUA+ replace the ICL7660 in an existing design?

Yes, the MAX860EUA+ can replace the ICL7660 with one wiring change: connect pin 7 (–S-H-D-N–) to VDD to enable operation (ICL7660's OSC pin is typically left floating). All other pins are functionally compatible. The MAX860EUA+ provides 5× higher output current, 4.6× lower output resistance, and selectable frequencies - significantly improving performance without layout redesign.

What is the output resistance of the MAX860EUA+ and how does it affect regulation?

The MAX860EUA+ has a typical output resistance of 12Ω, which causes predictable voltage droop under load: for example, with +5V input, output drops from –5.0V (no load) to –4.4V at 50mA. This resistance includes internal switch R_ON and is independent of external capacitors - enabling accurate rail budgeting without closed-loop regulation in moderate-precision applications.