Analog Devices Inc./Maxim Integrated MAX1817EUB

Overview

MAX1817EUB from Maxim Integrated is a compact, high-efficiency dual-output step-up DC-DC converter designed for portable electronics requiring simultaneous main logic supply and LCD bias generation. It delivers up to 125mA at 3.3V (fixed) or 2.5V–5.5V (adjustable) from 1.5V–5.5V input, supports up to +28V LCD output, achieves 88% peak efficiency, and features independent logic-controlled shutdown with 0.1µA quiescent current - enabling long battery life in PDAs, GPS receivers, and MP3 players.

For engineers reviewing the MAX1817EUB datasheet, MAX1817EUB pinout, MAX1817EUB application, or MAX1817EUB equivalent, key selection criteria include its dual regulated outputs, µMAX-10 package footprint, internal N-channel MOSFETs (0.35Ω main / 1.1Ω LCD), 1.25V feedback reference, and startup capability down to 1.2V under light load - all critical for low-voltage battery-powered designs.

Technical Context

The MAX1817EUB integrates two independent boost converters sharing a common bias rail (powered from OUT). The main converter uses a current-mode, discontinuous-conduction control scheme with zero-crossing detection and programmable on-time (2.4–7.5µs), while the LCD converter employs a minimum-off-time, current-limited architecture with fixed-frequency operation up to 500kHz. Both converters feature internal 0.35Ω (main) and 1.1Ω (LCD) N-channel MOSFET switches and 1.25V precision feedback references.

Startup is enabled by a dedicated oscillator that forces 50% duty cycle until VOUT exceeds 2.2V (typical undervoltage lockout), allowing reliable boot from two alkaline cells. Independent ON and ONLCD inputs provide separate enable/disable control, and the IC operates in bootstrap mode - eliminating need for external bias supply.

Key Specifications

Pinout & Package

The MAX1817EUB is housed in a 10-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced with exposed pad (not electrically connected). Pin 6 is no-connect; AGND and GND must be tied together near the IC for optimal noise immunity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output boost converter applications.

Compared with TPS61085DGRT and LT3467EDD, the MAX1817EUB uniquely integrates both main and LCD boost stages with internal MOSFETs in a 3mm × 3mm package - offering the smallest footprint and lowest component count for portable LCD applications requiring ≤125mA main current and ≤28V bias.

Availability

MAX1817EUB is available at Aetrix Electronics and suitable for handheld GPS receivers, portable media players, electronic organizers, and industrial handheld terminals requiring stable component supply with guaranteed long-term availability.

Supply support for MAX1817EUB 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 applications.

The MAX1817EUB belongs to Maxim's portable power management product line, engineered specifically for space-constrained, battery-powered devices needing dual regulated outputs - emphasizing low quiescent current, wide input range, and integrated switching elements.

FAQ

What is the minimum input voltage required for the MAX1817EUB to start up?

The MAX1817EUB can start up from as low as +1.2V under no-load conditions, and typically starts into a 35Ω load with +1.5V input - enabling reliable operation from two alkaline cells even in deep discharge. Startup voltage increases with load current, as shown in the Typical Operating Characteristics plot "STARTUP VOLTAGE vs. LOAD CURRENT" (Figure 3).

Can the MAX1817EUB generate negative LCD bias voltages?

Yes, the MAX1817EUB can generate negative LCD bias by adding an external diode-capacitor charge-pump circuit (e.g., D3, D4, C6) to the LXLCD pin, as shown in Figure 4 of the datasheet. The FBLCD feedback is referenced to the positive output, and the negative output magnitude is slightly reduced by one diode forward voltage drop relative to the positive-side capacitor voltage.

What is the purpose of the AGND and GND pins on the MAX1817EUB?

The MAX1817EUB separates analog ground (AGND) and power ground (GND) to isolate noise-sensitive feedback circuitry from high-current switching paths. AGND serves as the reference for FB and FBLCD inputs, while GND carries LX and LXLCD return currents. They must be connected together at a single point near the IC to prevent ground loops and ensure stable regulation.

How does the MAX1817EUB achieve 88% peak efficiency?

The MAX1817EUB achieves 88% peak efficiency through low R_DS(on) internal MOSFETs (0.35Ω main, 1.1Ω LCD), optimized control architecture minimizing switching and conduction losses, and support for high-frequency operation (up to 500kHz) that allows use of small, low-ESR external components - all detailed in the "MAIN OUTPUT EFFICIENCY vs. LOAD CURRENT" graph (Figure 1).

Is the MAX1817EUB pin-compatible with other devices in the MAX1817 family?

Yes, all MAX1817 variants - including MAX1817EUB, MAX1817EUK, and MAX1817EEE - share identical pinout and electrical specifications; only temperature grade and package differ. The MAX1817EUB (–40°C to +85°C, µMAX-10) is functionally and physically interchangeable with other members of the MAX1817 family in the same package.