Analog Devices Inc./Maxim Integrated MAX828EPA

Overview

The MAX828EPA from Maxim Integrated is a monolithic CMOS switched-capacitor voltage inverter that accepts +1.5V to +5.5V input and generates a regulated negative output up to −5V, delivering 25mA with 500mV dropout at full load, operating at 12kHz oscillator frequency, and featuring 60µA quiescent current - ideal for generating analog supply rails from single positive logic supplies in portable instrumentation.

For engineers reviewing the MAX828EPA datasheet, MAX828EPA pinout, MAX828EPA application, or MAX828EPA equivalent, key selection criteria include its SOT23-5 footprint compatibility, low-noise charge-pump architecture, efficiency above 94% at light loads, and absence of shutdown control - critical when designing compact, battery-sensitive analog subsystems requiring clean negative bias without external enable logic.

Technical Context

The MAX828EPA implements a two-phase, non-regulated charge-pump inverter using four on-chip power MOSFET switches and an internal oscillator fixed at 12kHz. It requires only two external capacitors (C1 flying, C2 reservoir) to invert VIN, with output voltage VOUT ≈ −(VIN − IOUT × RS−), where RS− is ~20Ω at +25°C and VIN = +5V.

No internal regulation or feedback loop exists; output droop scales linearly with load current due to switch resistance and capacitor ESR. Efficiency peaks above 95% at 5mA and declines as IOUT increases beyond 15mA, dominated by quiescent current at light loads and output impedance at heavier loads.

Key Specifications

Pinout & Package

MAX828EPA is housed in a 5-pin SOT23-5 surface-mount package with exposed pad (not electrically connected), measuring 2.9mm × 1.6mm × 1.1mm. Pin 1 is marked with a dot; pin numbering follows standard SOT23-5 top-view orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage inverter applications.

Compared with MAX828EPA, MAX829EPA offers higher frequency and lower impedance for improved transient response, while MAX860ESA+ provides double the output current in a different package - both require layout revision and capacitor value adjustment, making them functional alternatives rather than pin-compatible replacements.

Availability

MAX828EPA is available at Aetrix Electronics and suitable for portable medical sensors, LCD bias generation, battery-powered data loggers, industrial analog signal conditioning, and handheld test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX828EPA 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 systems.

The MAX828EPA belongs to Maxim's switched-capacitor voltage converter product line, engineered specifically for low-power, space-constrained applications needing clean, inductorless negative voltage generation from single-supply rails.

FAQ

What is the maximum output current specification for the MAX828EPA?

The MAX828EPA delivers up to 25mA output current with a 500mV voltage drop at full load when VIN = +5V and TA = +25°C. At lower input voltages (e.g., +2.0V), the maximum sustainable output current decreases to ~10mA due to reduced headroom and increased relative droop. The device's absolute maximum rated output current is 50mA, but sustained operation above 25mA risks excessive junction temperature rise in the SOT23-5 package without thermal relief.

Does the MAX828EPA include a shutdown control pin?

No, the MAX828EPA does not feature a dedicated shutdown pin. It operates continuously once powered. For logic-controlled enable/disable functionality, designers must implement external circuitry - such as an NMOS switch on the IN rail or a buffer-driven shutdown network per Figure 8 in the datasheet. Alternative parts like the MAX1719 offer integrated shutdown, but they are not pin-compatible with the MAX828EPA.

What capacitor values are recommended for stable operation of the MAX828EPA?

For stable operation, the MAX828EPA requires a 10µF low-ESR flying capacitor (C1) and a 10µF low-ESR reservoir capacitor (C2), both rated for ≥6.3V. Ceramic X5R/X7R or polymer tantalum types are preferred. Using smaller values (e.g., 4.7µF) increases output resistance and ripple; larger values (>22µF) yield diminishing returns due to dominance of internal switch resistance. A 0.1µF ceramic bypass capacitor on the IN pin is mandatory for noise suppression.

Can the MAX828EPA generate a regulated −5V output from a +5V input?

The MAX828EPA produces a non-regulated inverted output: VOUT ≈ −(VIN − IOUT × RS−). With VIN = +5V and no load, VOUT ≈ −4.8V to −4.9V due to internal losses; at 25mA, it drops to ~−4.5V. It cannot maintain a precise −5V rail under varying load - regulation requires external feedback or a post-regulator. For fixed −5V, consider pairing MAX828EPA with a low-dropout negative LDO like the LM7705.

Is the MAX828EPA RoHS-compliant and lead-free?

Yes, the MAX828EPA is RoHS-compliant and lead-free, meeting EU Directive 2011/65/EU and JEDEC J-STD-609 standards. The SOT23-5 package uses matte tin (Sn) lead finish, and the device is qualified for Pb-free reflow soldering per IPC/JEDEC J-STD-020. Full compliance documentation, including substance declarations and test reports, is available through Analog Devices' product change notifications (PCNs) for this part.