Analog Devices Inc./Maxim Integrated MAX860CPA

Overview

MAX860CPA from Maxim Integrated is a frequency-selectable switched-capacitor voltage converter that inverts +1.5V to +5.5V inputs or doubles +2.5V to +5.5V inputs, delivering up to 50mA output with 87% efficiency at full load, 200µA quiescent current, and 12Ω output resistance-ideal for low-noise, inductorless power rails in portable medical instruments and handheld test equipment.

For engineers reviewing the MAX860CPA datasheet, MAX860CPA pinout, MAX860CPA application, or MAX860CPA equivalent, key selection criteria include its three selectable switching frequencies (6/50/130kHz), active-low shutdown (<1µA), LV pin configuration for inverter/doubler mode, and compatibility with legacy ICL7660 sockets requiring only SHDN pin tie-high.

Technical Context

The MAX860CPA implements a BiCMOS charge-pump architecture with direct oscillator-to-switch coupling (no frequency division), enabling precise control of switching frequency via FC pin states (VDD/GND/OUT). Its internal switch resistance (~8Ω) combines with external capacitor ESR to define total output resistance (ROUT = RO + 4×ESR_C1 + ESR_C2 + 1/(f_S×C₁)).

Operation supports two distinct topologies: inverter mode (LV = GND) generating –V_IN, and doubler mode (LV = OUT) generating +2V_IN. Shutdown disables all active circuitry, reducing supply current to <1µA while preserving reverse-current paths dependent on load connection (VDD→OUT vs. OUT→GND).

Key Specifications

Pinout & Package

MAX860CPA is housed in an 8-pin plastic SO package (SOIC-8, 150mil width, outline 21-0041), with 1.27mm pitch, 5.0mm × 4.0mm footprint, and RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX660CPA and ICL7660CPA, the MAX860CPA offers mid-range current capability with programmable frequency-making it optimal for 20–50mA applications needing noise control and battery longevity, whereas MAX660CPA suits higher-current needs and ICL7660CPA fits ultra-low-cost micropower niches.

Availability

MAX860CPA is available at Aetrix Electronics and suitable for portable medical sensors, handheld test equipment, industrial interface power supplies, and operational amplifier supplies requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX860CPA 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, medical, and communications markets.

The MAX860/MAX861 product line was designed specifically to replace aging ICL7660-based solutions with higher efficiency, programmable frequency, and lower quiescent current-targeting battery-constrained portable instrumentation and noise-sensitive analog systems.

FAQ

What are the valid switching frequencies for MAX860CPA and how are they selected?

The MAX860CPA supports three switching frequencies: 6kHz (FC = VDD or open), 50kHz (FC = GND), and 130kHz (FC = OUT). These are selected solely by the voltage state applied to the FC pin-no external clock or configuration register is needed. The frequencies are fixed per device variant and cannot be adjusted beyond these three states. Each frequency trades off capacitor size, output ripple, and quiescent current, as documented in Table 2 of the MAX860CPA datasheet.

Can MAX860CPA replace ICL7660 in an existing design without PCB changes?

Yes, MAX860CPA is pin-compatible with ICL7660 in SO-8 packages, but one wiring change is required: pin 7 (SHDN) must be tied to VDD to enable operation, whereas ICL7660 pin 7 (OSC) is typically left floating. All other pins (VDD, GND, C1+, C1-, OUT, LV, FC) map directly. No layout changes are needed if the PCB uses standard SOIC-8 land patterns and accommodates the FC pin's frequency-selection function.

What is the maximum continuous output current specification for MAX860CPA?

The MAX860CPA is rated for 50mA continuous output current under specified conditions (VDD = +5V, TA ≤ +85°C, C1 = C2 = 10µF, low-ESR capacitors). Absolute maximum rating is 60mA, but sustained operation above 50mA risks exceeding thermal limits and degrading efficiency or reliability. Derating is required above +70°C ambient, with SO package power dissipation limited to 471mW at +70°C (derating 5.88mW/°C above).

How does the LV pin affect MAX860CPA operation and what happens if it's left unconnected?

The LV pin configures topology: LV = GND enables inverter mode (VOUT = –VDD); LV = OUT enables doubler mode (VOUT = +2VDD). If left floating, MAX860CPA defaults to inverter mode only when VDD > 3V; below 3V, floating LV causes undefined behavior and potential malfunction. For reliable operation, LV must be explicitly tied-never left floating-especially in battery-powered systems where VDD may sag below 3V during discharge.

What is the output resistance of MAX860CPA and how does it impact load regulation?

The MAX860CPA has a typical output resistance of 12Ω when tested with 10µF/0.2Ω ESR capacitors at 50mA load. This resistance causes voltage droop proportional to load current: e.g., at 50mA, VOUT drops by 0.6V from no-load value. Total ROUT includes internal switch resistance (~8Ω), capacitor ESR contributions, and 1/(fS×C1) term-so selecting higher fS or lower-ESR capacitors directly improves regulation. The datasheet provides ROUT calculation formulas for design optimization.