Analog Devices Inc./Maxim Integrated MAX860ESA+

Overview

MAX860ESA+ 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 12Ω output resistance and 200µA quiescent current. It serves as a compact, inductorless power solution for portable medical instruments and handheld test equipment.

For engineers reviewing the MAX860ESA+ datasheet, MAX860ESA+ pinout, MAX860ESA+ application, or MAX860ESA+ equivalent, key selection considerations include its -40°C to +85°C operating temperature range, SO-8 package compatibility, three-frequency FC pin control, and shutdown current below 1µA - all critical for low-power, space-constrained DC-DC conversion designs.

Technical Context

The MAX860ESA+ implements a BiCMOS charge-pump architecture with direct oscillator-to-switch coupling (no frequency division), enabling precise frequency selection via the FC pin (VDD/GND/OUT). Its LV pin configures mode: grounded for inversion, connected to OUT for doubling - distinct from legacy ICL7660/MAX660 pinouts.

It uses two external flying/output capacitors (C1/C2) with low-ESR requirements (<0.2Ω); output voltage droop is governed by ROUT = 8Ω + 4×ESR_C1 + ESR_C2 + 1/(f_S×C1), yielding ~600mV drop at 50mA under typical conditions. Shutdown disables internal circuitry, reducing supply current to <1µA while preserving reverse-current paths depending on load topology.

Key Specifications

Pinout & Package

MAX860ESA+ is housed in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm, with standard 1.27mm pitch and RoHS-compliant finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX860ESA+, MAX861ESA+ offers higher-frequency operation without layout changes, while MAX660CPA+ provides greater output current at the cost of pinout incompatibility and reduced light-load efficiency - making MAX860ESA+ optimal for new designs prioritizing low-quiescent-current, flexible frequency tuning, and industrial temperature range.

Availability

MAX860ESA+ is available at Aetrix Electronics and suitable for portable medical sensors, handheld test equipment, industrial interface modules, and low-power data acquisition systems requiring stable component supply across extended temperature ranges.

Supply support for MAX860ESA+ 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 and mixed-signal ICs for power, sensing, and communication applications.

The MAX860/MAX861 family was designed specifically to replace legacy charge pumps like the ICL7660 with higher efficiency, wider input range, and programmable frequency - targeting space- and power-constrained portable and industrial systems.

FAQ

What input voltage ranges does the MAX860ESA+ support in inverter vs. doubler mode?

The MAX860ESA+ accepts +1.5V to +5.5V in inverter mode (LV = GND) and +2.5V to +5.5V in doubler mode (LV = OUT). These ranges are strictly defined in the Absolute Maximum Ratings and Electrical Characteristics tables; operation outside them risks improper regulation or device stress. The MAX860ESA+ achieves stable inversion down to 1.5V, enabling use with partially discharged lithium cells - a key advantage over older charge pumps limited to ≥2.7V.

How does the FC pin affect capacitor selection for the MAX860ESA+?

The FC pin directly sets the MAX860ESA+ switching frequency (6kHz/50kHz/130kHz), which governs optimal C1/C2 values: lower frequencies require larger capacitors to maintain output resistance and ripple performance, while higher frequencies allow smaller, cheaper ceramics. For example, at 6kHz FC=VDD, Table 3 recommends 68µF C1; at 130kHz FC=OUT, only 4.7µF is needed. Using mismatched values degrades efficiency and increases voltage droop - verified in MAX860ESA+ Typical Operating Characteristics curves MAX860-08 through MAX860-09.

Can the MAX860ESA+ be used as a direct replacement for the ICL7660 in existing designs?

The MAX860ESA+ is pin-compatible with the ICL7660 only with one wiring modification: pin 7 (SHDN) must be tied to VDD (not left floating), and pin 1 (FC) can retain the original OSC connection since FC accepts VDD/GND/OUT. However, LV pin behavior differs - it must be grounded for inverter mode, unlike the ICL7660's unused pin. Full functional equivalence requires verifying load regulation and ripple under the new frequency profile, as MAX860ESA+'s 6kHz minimum is significantly higher than ICL7660's 5kHz.

What is the maximum allowable output short-circuit duration for the MAX860ESA+?

The MAX860ESA+ allows OUT to be shorted to GND for up to 1 second without damage, per Absolute Maximum Ratings. Shorting OUT to VDD is prohibited and may cause permanent failure. This 1s rating applies only at TA ≤ +85°C; above this temperature, any short-circuit - even instantaneous - risks device damage. Designers should implement current-limiting or fault-detection circuits in applications where sustained shorts are possible, as the MAX860ESA+ lacks internal foldback protection.

How does temperature affect the output resistance of the MAX860ESA+?

MAX860ESA+ output resistance (RO) increases with temperature: Typical Operating Characteristic curve MAX860-04 shows RO rising from ~8Ω at –40°C to ~16Ω at +125°C (extrapolated), with ~12Ω at +25°C. This variation directly impacts load regulation - e.g., a 50mA load causes ~600mV drop at +25°C but ~1.2V drop at +125°C. Designers must account for this in worst-case margining, especially in automotive or industrial environments where ambient extremes affect RO more than input voltage changes.