Analog Devices Inc./Maxim Integrated MAX1735EUK50+T

Overview

MAX1735EUK50+T from Maxim Integrated is a negative-output, low-dropout linear regulator delivering guaranteed 200mA at -5.0V with 80mV dropout at full load, ±1% output accuracy, and 85µA quiescent current-designed for GaAsFET bias, mobile wireless data modems, and portable instrumentation requiring stable negative rail generation.

For engineers reviewing the MAX1735EUK50+T datasheet, MAX1735EUK50+T pinout, MAX1735EUK50+T application, or MAX1735EUK50+T equivalent, key selection criteria include guaranteed -5.0V output, SOT23-5 thermal performance, shutdown threshold compatibility with TTL/CMOS logic, and stability with 1µF ceramic output capacitance.

Technical Context

The MAX1735EUK50+T uses an internal N-channel MOSFET pass element enabling ultra-low quiescent current (85µA typical) independent of load, with dropout defined as V_OUT − V_IN at 100mV above nominal output. Its Dual Mode™ architecture supports fixed -5.0V operation when SET is grounded, eliminating external feedback components.

Regulation relies on a precision -1.25V internal reference and error amplifier driving the MOSFET; SHDN accepts bipolar logic thresholds (|V_SHDN| > 1.6V to enable, < 0.4V to disable), allowing direct interface with standard 5V TTL without level shifting.

Key Specifications

Pinout & Package

Package: SOT23-5 (5-pin surface-mount, 1.6mm × 2.9mm × 1.1mm, thermal pad not present; IN pin serves as heatsink-requires large PCB copper area).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative-output LDO regulator applications.

Compared with LT1963AES5-5#TRPBF and TPS72325DBVR, the MAX1735EUK50+T uniquely delivers factory-set -5.0V output in SOT23-5 with sub-100µA quiescent current and bipolar shutdown logic-making it irreplaceable for space-constrained, battery-powered negative-rail applications without architectural changes.

Availability

MAX1735EUK50+T is available at Aetrix Electronics and suitable for mobile wireless data modems, GaAsFET bias supplies, and portable instrumentation amplifiers requiring stable component supply, long-lifecycle support, and traceable sourcing for production programs.

Supply support for MAX1735EUK50+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) designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.

The MAX1735 series belongs to Maxim's high-efficiency negative LDO family, engineered specifically for battery-powered portable equipment requiring ultra-low IQ, bipolar logic compatibility, and compact negative rail generation without external feedback networks.

FAQ

What is the guaranteed output voltage tolerance for MAX1735EUK50+T over temperature and load?

The MAX1735EUK50+T guarantees ±1% output voltage accuracy over the full -40°C to +85°C operating temperature range and across the full 0mA to 200mA load current range. This specification is confirmed in the Electrical Characteristics table under "Output Voltage Accuracy" with test conditions including I_LOAD = -100µA to -200mA and TA = 0°C to +85°C. The MAX1735EUK50+T achieves this via factory laser-trimming of internal feedback resistors and a precision -1.25V reference.

Can MAX1735EUK50+T be used with a 1µF ceramic output capacitor, and why is this significant?

Yes, the MAX1735EUK50+T is stable with a minimum 1µF ceramic output capacitor-explicitly guaranteed in the datasheet's "Stable with 1µF C_OUT" feature and Electrical Characteristics. This eliminates the need for larger, higher-ESR tantalum or electrolytic capacitors, reducing cost, board area, and reliability risk. The MAX1735EUK50+T achieves this via internal compensation optimized for low-ESR ceramics, making it ideal for space-constrained portable designs where every mm² matters.

Does MAX1735EUK50+T support shutdown using standard 5V TTL logic levels?

Yes, the MAX1735EUK50+T SHDN pin accepts standard 5V TTL logic: driving SHDN to ≥+1.6V (e.g., 3.3V or 5V CMOS high) enables regulation, while pulling SHDN to GND disables it-consuming only 1nA. Its bipolar threshold design (|V_SHDN| < 0.4V = shutdown, >1.6V = active) allows direct connection to microcontroller GPIOs without level shifters. This behavior is documented in the SHDN Input High/Low Threshold specs and Typical Operating Characteristics plots.

What thermal considerations apply to MAX1735EUK50+T in a SOT23-5 package at maximum load?

The MAX1735EUK50+T in SOT23-5 has a junction-to-ambient thermal resistance (θ_JA) of ~140°C/W in typical layouts. At 200mA and 1.5V input-output differential (e.g., VIN = -6.5V), power dissipation is ~300mW, raising junction temperature by ~42°C above ambient. To stay within the +150°C absolute max, ambient must remain ≤+108°C-so PCB layout is critical: solder IN (Pin 2) to ≥10mm² copper pour and avoid enclosed enclosures. Thermal shutdown activates at +160°C with 15°C hysteresis.

Is MAX1735EUK50+T pin-compatible with other MAX1735 variants like MAX1735EUK30+T?

Yes, all MAX1735 variants-including MAX1735EUK50+T, MAX1735EUK30+T, and MAX1735EUK25+T-share identical SOT23-5 packaging, pinout, and electrical interface. They differ only in factory-trimmed output voltage (-5.0V, -3.0V, or -2.5V) and top-mark codes (ADOZ, ADOY, ADOX). No PCB layout change is required when substituting between these variants, provided the system's required output voltage matches the selected part's preset value.