Analog Devices Inc./Maxim Integrated MAX1733EUK-T

Overview

MAX1733EUK-T from Maxim Integrated is a synchronous step-down DC-DC converter delivering 250mA at adjustable output voltages from 1.25V to 2.0V, operating from 2.7V–5.5V input, with 40µA quiescent current and 1.2MHz max switching frequency. It integrates high-side and low-side MOSFETs in a 5-pin SOT23 package and targets space-constrained battery-powered logic supplies.

For engineers reviewing the MAX1733EUK-T datasheet, MAX1733EUK-T pinout, MAX1733EUK-T application, or MAX1733EUK-T equivalent, key selection criteria include its adjustable feedback threshold (1.25V), ±1.5% initial output accuracy, internal soft-start, shutdown current of 0.01µA, and compatibility with ceramic or tantalum output capacitors in compact portable designs.

Technical Context

The MAX1733EUK-T employs a proprietary current-limited control scheme with fixed minimum on-time (0.25–0.55µs) and off-time (0.25–0.55µs), enabling stable operation across light-to-heavy loads while maintaining high efficiency (>90%) via internal synchronous rectification. Its FB pin regulates to a precise 1.25V reference, supporting external resistor-divider programming of VOUT.

It features active-low SHDN with 0.4V logic-low threshold and 1.6V logic-high threshold, integrated digital soft-start that ramps current limit in 25% steps, and UVLO with 1.55V falling-edge threshold and 200mV hysteresis. The LX pin drives an external 10µH inductor and supports ceramic COUT when reconfigured per Figure 3.

Key Specifications

Pinout & Package

MAX1733EUK-T is housed in a RoHS-compliant (lead-free option available) 5-pin SOT23-5 package (drawing code 21-0057F, variation U5-1*), with 0.9mm body height, 1.6mm × 2.9mm footprint, and gull-wing leads for surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down DC-DC converter applications.

Compared with MAX1733EUK-T, TPS62231DRYR offers higher switching frequency and lower IQ but lacks output adjustability, while RT8059GJ6 provides greater current headroom and broader VOUT range at the cost of larger package size and different pinout-neither is pin-compatible, and both require schematic and layout updates.

Availability

MAX1733EUK-T is available at Aetrix Electronics and suitable for cellular handset core supplies, PDA logic rails, wireless headset audio codec power, and industrial sensor node MCU supplies requiring stable component supply with long lifecycle visibility.

Supply support for MAX1733EUK-T 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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX1733EUK-T belongs to Maxim's low-voltage DC-DC converter product line, designed specifically for space-constrained, battery-powered systems needing high efficiency, ultra-low quiescent current, and simple external component count.

FAQ

What is the maximum output current supported by the MAX1733EUK-T?

The MAX1733EUK-T guarantees 250mA output current across its full operating temperature range (-40°C to +85°C) and input voltage range (2.7V to 5.5V). This rating assumes proper thermal design-including adequate PCB copper area for the GND pad-and use of a 10µH inductor rated for ≥300mA saturation current. Peak current capability reaches 535mA due to internal high-side current limiting.

How do I set the output voltage for the MAX1733EUK-T?

To set the output voltage for the MAX1733EUK-T, connect the FB pin to a resistive divider between VOUT and GND. Use R2 ≤ 50kΩ and calculate R1 = R2 × (VOUT / 1.25V − 1). For example, for 1.8V output: R1 = R2 × (1.8 / 1.25 − 1) = R2 × 0.44. The MAX1733EUK-T's internal 1.25V reference ensures ±1.5% initial accuracy over temperature and line/load conditions.

Does the MAX1733EUK-T support ceramic output capacitors?

Yes, the MAX1733EUK-T supports ceramic output capacitors when configured per Figure 3 in the datasheet-using the LX pin instead of VOUT for feedback. This configuration removes phase lag, enabling stable operation with 2.2µF–4.7µF X7R ceramics, reducing output ripple to <10mVp-p and shrinking PCB area versus tantalum solutions. Standard configurations require 22µF tantalum with 200–300mΩ ESR.

What is the shutdown current of the MAX1733EUK-T?

The MAX1733EUK-T draws only 0.01µA supply current in shutdown mode when the SHDN pin is pulled low to GND. During shutdown, the internal control circuitry, high-side switch, and synchronous rectifier are disabled, and the LX pin enters high-impedance state. This ultra-low shutdown current makes the MAX1733EUK-T ideal for battery-backed real-time clocks and always-on sensor nodes.

Is the MAX1733EUK-T RoHS compliant?

The MAX1733EUK-T is not RoHS/lead-free compliant; it uses standard SnPb terminations. However, the lead-free variant MAX1733EUK+T (same SOT23-5 package, U5+1* variation) is available and fully RoHS compliant. Both share identical electrical specifications and thermal performance-only the finish differs. Always verify packaging suffix and drawing code (U5-1* vs. U5+1*) when ordering.