Analog Devices Inc./Maxim Integrated MAX1697SEUT

Overview

MAX1697SEUT from Maxim Integrated is a monolithic CMOS inverting charge-pump DC-DC converter delivering -1×VIN output with 60mA load capability, 12Ω typical output resistance, and 250kHz fixed switching frequency. It operates from +1.25V to +5.5V input, features logic-controlled shutdown, and targets space-constrained analog biasing in portable electronics.

For engineers reviewing the MAX1697SEUT datasheet, MAX1697SEUT pinout, MAX1697SEUT application, or MAX1697SEUT equivalent, key selection criteria include output current at 250kHz operation, shutdown leakage (<10nA), thermal shutdown threshold (+150°C), and SOT23-6 package compatibility with low-ESR ceramic capacitor requirements.

Technical Context

The MAX1697SEUT implements a two-phase switched-capacitor inverter using four on-chip power MOSFETs to generate regulated negative voltage without inductors. Its internal oscillator runs at 250kHz (U-suffix), enabling compact 1µF flying and output capacitors while maintaining ≤12Ω output impedance across -40°C to +85°C.

Shutdown mode actively pulls OUT to GND via 3Ω internal switch and reduces supply current to 2nA. Thermal shutdown disables switching above +150°C with 15°C hysteresis, and start-up current is limited to 170mA (typ) to protect weak input sources like alkaline batteries.

Key Specifications

Pinout & Package

MAX1697SEUT is housed in a 6-pin SOT23 package (U6F-6 outline), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and RoHS-compliant lead-free finish (top mark: AABY).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX1697SEUT, the MAX1697TEUT trades higher output impedance for improved efficiency at partial load and lower EMI, while the MAX1720EUT sacrifices output current capability to achieve sub-200µA operating current - neither matches the 60mA/250kHz performance envelope of MAX1697SEUT.

Availability

MAX1697SEUT is available at Aetrix Electronics and suitable for battery-operated equipment, small LCD panels, and GaAsFET bias supplies requiring stable component supply with guaranteed long-term availability.

Supply support for MAX1697SEUT 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 industrial, automotive, and communications markets.

The MAX1697 series was developed specifically for compact, inductorless negative voltage generation in space-constrained portable electronics, emphasizing low ESR capacitor compatibility and robust thermal behavior.

FAQ

What is the exact switching frequency of MAX1697SEUT and how is it set?

The MAX1697SEUT has a fixed 250kHz oscillator frequency determined by internal circuitry - no external components or configuration pins are required. This frequency is encoded in the 'U' suffix per Maxim's ordering table and enables use of 1µF ceramic flying and output capacitors while maintaining low output impedance. The 250kHz operation directly defines the device's trade-off between capacitor size, output ripple, and efficiency across its 60mA load range.

Does MAX1697SEUT require external diodes or inductors in standard inverter configuration?

No, MAX1697SEUT requires no external diodes or inductors in its standard inverting configuration. It integrates four power MOSFET switches and oscillator control circuitry on-die, needing only two external 1µF ceramic capacitors (C1 and C2) plus an optional input bypass capacitor. This fully integrated architecture eliminates magnetic components, reduces EMI susceptibility, and simplifies layout - a core design objective confirmed in the device's "Typical Operating Circuit" and "Detailed Description" sections.

What is the shutdown behavior of MAX1697SEUT and how does it affect the output pin?

When SHDN is driven low, MAX1697SEUT enters shutdown mode: switching halts, supply current drops to 2nA, and the OUT pin is actively pulled to GND through a 3Ω internal switch. This behavior is explicitly specified in the Electrical Characteristics table under "OUT to GND Shutdown Resistance" and "Shutdown Supply Current". It ensures predictable, low-impedance discharge of downstream capacitance - critical for system-level power sequencing and safety in battery-powered devices.

Can MAX1697SEUT operate from a 1.5V alkaline cell, and what limits its minimum input voltage?

Yes, MAX1697SEUT operates down to +1.25V input, making it compatible with partially discharged 1.5V alkaline cells. Its minimum input is limited by internal bias circuitry and switch threshold voltages - confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. At 1.25V, output current capability reduces due to higher relative losses, but the device remains functional. Startup current limiting (170mA typ) prevents cell voltage collapse during initial charge pump engagement.

How does MAX1697SEUT's output resistance vary with temperature and load?

MAX1697SEUT's output resistance is 12Ω typical at +25°C and increases to ~17Ω at +85°C, as shown in the "OUTPUT RESISTANCE vs. TEMPERATURE" plot (TOC15). It remains relatively flat across 1–60mA loads at fixed temperature but rises slightly under heavy load due to MOSFET R_DS(on) heating. This behavior is documented in the Typical Operating Characteristics section and directly impacts voltage regulation accuracy - e.g., 720mV droop at 60mA and +85°C versus 600mV at +25°C.