Analog Devices Inc./Maxim Integrated MAX683EUA

Overview

MAX683EUA from Maxim Integrated is a 5V charge-pump voltage regulator IC designed for compact, low-noise auxiliary power in battery-powered systems. It accepts 2.7V–5.5V input, delivers up to 100mA output current, regulates output to ±4% accuracy, operates in skip or constant-frequency mode (50kHz–2MHz), and uses only three external capacitors and one resistor-no inductor required. It serves as a space-constrained 3.3V-to-5V local converter in PCMCIA cards and flash memory supplies.

For engineers reviewing the MAX683EUA datasheet, MAX683EUA pinout, MAX683EUA application, or MAX683EUA equivalent, this page provides verified technical context, validated pin functions, confirmed operating modes (SKIP/SHDN control), real-world efficiency curves at 3.3V/5V input, and precise capacitor sizing guidance for both skip and constant-frequency operation.

Technical Context

The MAX683EUA implements a regulated charge-pump topology with dual-mode control: SKIP = low enables pulse-skipping for ultra-low quiescent current (100µA), while SKIP = high forces constant-frequency switching to minimize output ripple. Its internal architecture includes a 1.23V bandgap reference, error amplifier, oscillator, and high-current MOSFET switches-all integrated into an 8-pin µMAX package.

Regulation is achieved by modulating charge transfer across the external CX capacitor (CXP/CXN terminals) based on feedback from the fixed 5V output. SHDN performs dual function: shutdown control and oscillator frequency programming via external resistor (REXT), with f_OSC = 45000(V_IN − 0.69V)/R_EXT (kHz), supporting 50kHz–2MHz tuning.

Key Specifications

Pinout & Package

The MAX683EUA is housed in an 8-pin µMAX package (3mm × 3mm, 1.1mm height), optimized for space-constrained applications including PCMCIA cards and miniature equipment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX682ESA and MAX684EUA, the MAX683EUA uniquely balances 100mA capability, µMAX form factor, and dual-mode flexibility-making it optimal for mid-power portable applications where space, efficiency, and ripple are jointly constrained.

Availability

MAX683EUA is available at Aetrix Electronics and suitable for flash memory supplies, battery-powered medical devices, and PCMCIA card designs requiring stable component supply, long-term lifecycle support, and guaranteed µMAX package availability.

Supply support for MAX683EUA 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 markets.

The MAX682/MAX683/MAX684 family was engineered specifically for compact, inductorless 3.3V-to-5V conversion in space- and power-constrained portable electronics-including memory cards, handheld instruments, and SIMM interfaces.

FAQ

What is the maximum output current supported by the MAX683EUA?

The MAX683EUA delivers up to 100mA of continuous output current, with a peak rating of 150mA. This is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics section of the datasheet. The MAX683EUA's 100mA capability positions it between the 250mA MAX682ESA and 50mA MAX684EUA variants-making it ideal for mid-range portable loads such as flash memory controllers and low-power peripherals. Exceeding 100mA risks thermal shutdown or regulation loss, especially in the 8-pin µMAX package.

Can the MAX683EUA operate from a 5V input source?

Yes, the MAX683EUA supports input voltages from 2.7V to 5.5V-but only when SKIP is held high. The datasheet explicitly states that "Regulation with VIN > 3.6V requires SKIP = high." If SKIP is low, the input range is restricted to 2.7V–3.6V. This constraint ensures stable regulation and prevents excessive power dissipation. Therefore, for 5V operation, the SKIP pin must be tied to VIN or a logic-high voltage, forcing constant-frequency mode and enabling full 5.5V tolerance.

How is the switching frequency set on the MAX683EUA?

The switching frequency of the MAX683EUA is programmed via the SHDN pin using an external resistor (REXT) connected between VIN and SHDN. The relationship is defined as R_EXT (kΩ) = 45000(V_IN − 0.69V) / f_OSC (kHz), supporting 50kHz–2MHz. SHDN behaves as a diode-connected input: sourcing 1–50µA sets frequency, while sinking <1µA places MAX683EUA in shutdown. This dual-function pin eliminates the need for dedicated frequency-setting pins, simplifying layout and reducing BOM count.

What capacitor values are recommended for the MAX683EUA in constant-frequency mode?

For constant-frequency operation (SKIP = high, ISHDN = 22µA, f_OSC ≈ 1MHz), the datasheet recommends C_X = 0.22µF, C_IN = 0.47µF, and C_OUT = 1µF (ceramic). These values minimize total solution size while maintaining ≤80mV output ripple. All capacitors must have low ESR (<100mΩ); ceramic types are preferred for lowest ripple, though tantalum (e.g., AVX TPS-series) is acceptable where bias stability is critical. Larger C_OUT reduces ripple further but increases board area and cost.

Does the MAX683EUA include undervoltage lockout protection?

Yes, the MAX683EUA incorporates an undervoltage lockout (UVLO) feature that disables regulation when the input voltage falls below 2.25V (typical), with 100mV hysteresis. This prevents unregulated output and protects downstream 5V logic from brownout conditions. UVLO activation is independent of SKIP or SHDN state-it engages automatically during deep discharge or weak battery conditions. Recovery occurs only after VIN rises above 2.35V, ensuring stable re-start without oscillation.