Analog Devices Inc./Maxim Integrated MAX860IUA+T

Overview

MAX860IUA+T from Maxim Integrated is a frequency-selectable, 50mA switched-capacitor voltage converter that inverts +1.5V to +5.5V inputs or doubles +2.5V to +5.5V inputs. It operates at selectable switching frequencies of 6kHz, 50kHz, or 130kHz, delivers 87% efficiency at 50mA load, and features 12Ω output resistance and 200µA quiescent current. It serves as a compact, inductorless power solution for portable medical instruments and handheld test equipment.

For engineers reviewing the MAX860IUA+T datasheet, MAX860IUA+T pinout, MAX860IUA+T application, or MAX860IUA+T equivalent, key selection criteria include its three-frequency control (FC) capability, low-quiescent-current shutdown (<1µA), µMAX-8 package compatibility with space-constrained PCBs, and verified performance in inverter/doubler topologies without external inductors.

Technical Context

The MAX860IUA+T implements a BiCMOS charge-pump architecture with direct oscillator-to-switch coupling-no frequency division-enabling precise frequency selection via FC pin states (VDD, GND, or OUT). Its LV pin configures mode: grounded for inverting operation, connected to OUT for doubling.

It achieves stable output regulation through passive capacitor-based impedance control: output source resistance (RO ≈ 8Ω) combines with flying/output capacitor ESR and 1/(f_S×C₁) term to define total ROUT (typically 12Ω with 10µF/0.2Ω ESR caps). Shutdown disables all active circuitry, reducing supply current to <1µA while preserving reverse-current paths dependent on topology.

Key Specifications

Pinout & Package

MAX860IUA+T is housed in an 8-pin µMAX® package (1.11mm height, 3mm × 3mm footprint), RoHS-compliant, with exposed pad for thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switched-capacitor voltage converter applications.

Compared with MAX861IUA+T, MAX860IUA+T offers lower quiescent current and reduced EMI at low frequencies but sacrifices high-frequency ripple suppression; versus MAX660CPA+, it provides superior efficiency, finer frequency granularity, and smaller external components-making it optimal for new designs targeting compact, battery-efficient systems.

Availability

MAX860IUA+T is available at Aetrix Electronics and suitable for portable medical sensors, handheld test equipment, interface power supplies, and operational-amplifier power supplies requiring stable component supply and long-term production continuity.

Supply support for MAX860IUA+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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and communications markets.

The MAX860/MAX861 product line was designed specifically to replace inductor-based DC-DC converters and legacy charge pumps (e.g., ICL7660) in space- and power-constrained applications requiring clean, efficient voltage inversion or doubling.

FAQ

What are the valid switching frequencies for MAX860IUA+T and how are they selected?

The MAX860IUA+T supports three discrete switching frequencies: 6kHz (FC = VDD or open), 50kHz (FC = GND), and 130kHz (FC = OUT). These are selected solely by the DC voltage level applied to the FC pin-no external clock or configuration register is involved. Frequency choice directly impacts capacitor sizing, output ripple, and quiescent current, as documented in Table 2 of the datasheet.

Can MAX860IUA+T be used as both an inverter and a doubler, and how is the mode configured?

Yes, MAX860IUA+T operates in either inverter or doubler mode depending on the LV pin connection: tie LV to GND for inverting (e.g., +5V → −5V), or to OUT for doubling (e.g., +5V → +10V). The pin configuration is hardware-selectable with no firmware or timing constraints, and both modes share identical electrical specifications except for input voltage range and no-load supply current.

What is the maximum continuous output current of MAX860IUA+T and what limits it?

The MAX860IUA+T delivers up to 50mA continuous output current under specified conditions (VDD = +5V, T_A ≤ +85°C, proper capacitor selection). This limit is determined by internal switch resistance, thermal dissipation in the µMAX-8 package (362mW max at +70°C), and output resistance-induced voltage droop-exceeding 50mA risks violating the 600mV drop specification and triggering thermal shutdown in sustained operation.

How does the shutdown function work on MAX860IUA+T and what is its effect on system power?

The SHDN pin on MAX860IUA+T is active-low: pulling it below 0.3V disables all internal circuitry, reducing supply current to less than 1µA. In inverter mode, loads between OUT and GND are unpowered; however, reverse current can flow from VDD to OUT via internal diodes. This behavior is explicitly characterized in the datasheet's Detailed Description section and must be accounted for in low-power system architecture.

Is MAX860IUA+T pin-compatible with older charge pumps like the ICL7660 or MAX660?

MAX860IUA+T is not pin-compatible with ICL7660 or MAX660 due to functional pin reassignments: pin 7 is SHDN (not OSC), and pin 1 is FC (not NC or OSC). However, it can be retrofitted into existing sockets with minimal wiring changes-SHDN must be jumpered to VDD (inverter) or GND (doubler), and FC may remain floating or connected per desired frequency-enabling upgrade paths without PCB revision.