Analog Devices Inc./Maxim Integrated MAX865EUA+

Overview

MAX865EUA+ from Maxim Integrated is a CMOS dual-output charge-pump DC-DC converter in an 8-pin µMAX package. It generates +2×VIN and −2×VIN outputs from a single +1.5V to +6.0V input, requires only four external capacitors, delivers up to 20mA per rail, and operates with a guaranteed 20kHz–38kHz oscillator frequency. It is used in low-voltage GaAsFET biasing and split-supply analog circuitry.

For engineers reviewing the MAX865EUA+ datasheet, MAX865EUA+ pinout, MAX865EUA+ application, or MAX865EUA+ equivalent, key selection considerations include its dual-rail charge-pump topology, 75Ω typical output impedance, −40°C to +85°C operating range, and compact 1.11mm-height µMAX footprint for space-constrained portable designs.

Technical Context

The MAX865EUA+ implements a two-stage switched-capacitor architecture: first a voltage-doubling stage (V+ = +2×VIN), then an inverting stage referenced to V+ (V− = −2×VIN). Its internal oscillator drives complementary CMOS power switches-four P-channel and four N-channel MOSFETs-with fixed 50% duty cycle.

Output regulation is unregulated; V+ and V− droop linearly with load current due to inherent source resistance (140Ω typ. for V+, 100Ω typ. for V− at +25°C). Ripple is determined by pump/reservoir capacitance and load, e.g., 10mV_p-p at 5mA with 3.3µF capacitors and 30kHz f_PUMP.

Key Specifications

Pinout & Package

The MAX865EUA+ is housed in an 8-pin µMAX package (3.05mm × 3.05mm × 1.11mm), occupying half the board area of standard SOIC-8. Pin 5 is GND; pins 1, 3, 4, 7, and 8 are dedicated flying/reservoir capacitor terminals and outputs; pins 2 and 6 are C2+ and IN respectively.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX864EUA+, the MAX865EUA+ offers lower quiescent current and simpler control interface but lacks shutdown; compared with TC7660HCOA, it delivers true dual-rail output with integrated switching, eliminating external diodes and enabling smaller total solution size despite narrower temperature rating.

Availability

MAX865EUA+ is available at Aetrix Electronics and suitable for low-voltage GaAsFET biasing, split-supply analog signal chains, and LCD panel biasing requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX865EUA+ 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) designs precision analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX865EUA+ belongs to Maxim's charge-pump DC-DC converter family, engineered specifically for compact, low-noise, dual-rail voltage generation in battery-powered RF and portable analog systems.

FAQ

What is the absolute maximum input voltage rating for the MAX865EUA+?

The MAX865EUA+ has an absolute maximum input voltage rating of +6.2V on the IN pin relative to GND. Exceeding this voltage-even momentarily-may cause permanent damage. The recommended operating range remains +1.5V to +6.0V. Always include transient suppression (e.g., TVS diode) if the input source is subject to surges, as the MAX865EUA+ contains no built-in overvoltage protection.

Can the MAX865EUA+ generate regulated outputs?

No, the MAX865EUA+ is an unregulated charge-pump converter. Its V+ and V− outputs follow a linear droop relationship: V+ ≈ 2×VIN − I_V+×R_S+, V− ≈ −(2×VIN − I_V+×R_S+ − I_V−×R_S−). Output voltage accuracy depends entirely on input stability, load current, capacitor ESR, and temperature. For regulated ±5V, pair MAX865EUA+ with low-dropout post-regulators like MAX1725.

What capacitor types and values are recommended for the MAX865EUA+?

Use 3.3µF polarized electrolytic or ceramic capacitors for all four external components (C1–C4) in most applications. Ceramic capacitors reduce ESR and improve efficiency but require careful DC-bias derating. For space-constrained designs drawing ≤2mA, 1µF capacitors are acceptable-though ripple increases to ~25mV_p-p at 5mA. C2 and C4 must be rated for ≥12V working voltage.

How does paralleling multiple MAX865EUA+ devices affect performance?

Paralleling two or more MAX865EUA+ ICs reduces effective output resistance by the number of units (e.g., two devices yield ~70Ω for V+), improving load regulation and reducing ripple. Each device requires its own C1 and C2 flying capacitors, but C3 and C4 reservoir capacitors may be shared. Ensure tight layout matching and identical capacitor values to prevent current imbalance and thermal runaway.

Does the MAX865EUA+ include thermal shutdown or short-circuit protection?

No, the MAX865EUA+ has no internal thermal shutdown or output short-circuit protection. The V− output is short-circuit tolerant to GND indefinitely, but V+ is not. Continuous operation above 330mW power dissipation (at +70°C ambient) risks reliability degradation. For high-current or fault-prone applications, add external current limiting (e.g., series resistors) and thermal monitoring.