Analog Devices Inc./Maxim Integrated MAX1853EXT

Overview

The MAX1853EXT from Maxim Integrated is a monolithic CMOS inverting charge-pump DC-DC converter in a 6-pin SC70 package, designed to generate a regulated negative output voltage (–1 × VIN) from +2.5V to +5.5V inputs. It delivers up to 30mA output current with 15Ω typical output resistance at 200kHz switching frequency and supports logic-controlled shutdown with 0.1µA quiescent current. It is used in portable analog circuitry requiring compact, low-noise negative bias from single-supply logic rails.

For engineers reviewing the MAX1853EXT datasheet, MAX1853EXT pinout, MAX1853EXT application, or MAX1853EXT equivalent, key selection criteria include its 200kHz oscillator frequency, ultra-low 0.68µF external capacitor requirement, –1× inversion ratio, SC70 package footprint, and compatibility with 3.3V/5V logic supply domains.

Technical Context

The MAX1853EXT integrates four on-chip power-MOSFET switches and oscillator control circuitry to implement a two-phase switched-capacitor inverter topology. It operates exclusively at 200kHz (not adjustable), enabling smaller external capacitors than the 50kHz MAX1852EXT variant while maintaining identical 15Ω output resistance and 30mA output capability.

Its shutdown function disables internal switching and reduces supply current to ≤0.5µA across temperature, with SHDN input threshold defined as 0.7×VIN (high) and 0.3×VIN (low). Output voltage regulation relies on fixed charge-transfer ratio rather than feedback control, resulting in –VIN ±2% typical accuracy under 10mA load with +5V input.

Key Specifications

Pinout & Package

The MAX1853EXT is housed in a 6-pin SC70 package (40% smaller than SOT23), with 0.65mm lead pitch and exposed pad not connected internally. Thermal performance supports 245mW continuous dissipation at +70°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1852EXT and TPS60403DBVR, the MAX1853EXT offers the smallest footprint and lowest capacitor count for 30mA inverting conversion, trading slightly higher quiescent current than MAX1852EXT for significantly reduced external component volume and EMI profile versus TPS60403DBVR.

Availability

MAX1853EXT is available at Aetrix Electronics and suitable for battery-powered equipment, handheld terminals, small LCD panels, and GaAsFET bias supplies requiring stable component supply across long-lifecycle industrial and medical programs.

Supply support for MAX1853EXT 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 MAX1852/MAX1853 product line was engineered for space-constrained, battery-sensitive systems needing efficient, capacitor-only voltage inversion - targeting portable instrumentation, handheld computing, and RF biasing where inductors are prohibited.

FAQ

What is the switching frequency of the MAX1853EXT?

The MAX1853EXT operates at a fixed 200kHz switching frequency, as specified in its ordering information and electrical characteristics table. This frequency is factory-trimmed and not user-adjustable. It enables the use of smaller 0.68µF external capacitors compared to the 50kHz MAX1852EXT, reducing solution size and cost. The MAX1853EXT datasheet confirms this value is guaranteed over the full –40°C to +85°C operating temperature range.

Can the MAX1853EXT generate output voltages other than –1× VIN?

No, the MAX1853EXT is a fixed-ratio inverting charge pump and only produces –1× VIN output voltage. Its internal switch matrix and timing are optimized solely for polarity inversion with unity magnitude. Unlike programmable or cascaded architectures (e.g., MAX865), it lacks pins or control logic for voltage doubling, tripling, or adjustable ratios. Attempting to modify external components will not change the nominal output ratio, though load and input variations cause predictable deviations per the output resistance specification.

What is the minimum input voltage required for reliable operation of the MAX1853EXT?

The MAX1853EXT requires a minimum input voltage of +2.5V, as stated in its Absolute Maximum Ratings and Electrical Characteristics tables. Below this, the internal charge-pump switches cannot fully enhance, leading to excessive output resistance, unstable startup, and failure to reach 90% of nominal –VIN output. At +2.5V input, the device still delivers 30mA output with 15Ω typical resistance, making it compatible with single-cell Li-ion (2.7–4.2V) and regulated 2.5V system rails.

Does the MAX1853EXT require an external feedback resistor network?

No, the MAX1853EXT does not use external feedback resistors because it is an open-loop, fixed-ratio charge pump - not a regulated DC-DC converter. Its output voltage is determined solely by the input voltage and internal switch characteristics, with no error amplifier or voltage reference. Stability and accuracy depend entirely on input rail quality, capacitor ESR, and load current. Adding resistive dividers or compensation networks has no functional effect and is not supported by the MAX1853EXT pinout or application circuits.

How does the shutdown feature of the MAX1853EXT behave during power-up?

The MAX1853EXT enters normal operation only when SHDN is driven high (≥0.7×VIN) after IN reaches valid voltage; if SHDN is low or floating at power-up, the device remains in shutdown with <0.5µA supply current until SHDN is asserted. There is no built-in power-on reset or delay - wake-up time is 112µs to 90% of final output voltage under 5mA load, as measured in the Typical Operating Characteristics. Pulling SHDN high before or simultaneously with IN ensures immediate start-up without sequencing constraints.