Analog Devices Inc./Maxim Integrated MAX8868EUK50

Overview

MAX8868EUK50 from Maxim Integrated is a low-noise, low-dropout linear regulator with 5.0V preset output, 150mA output current capability, 30µVRMS output noise, and 165mV dropout at full load. It features auto-discharge on shutdown, reverse battery protection, and operates from 2.5V to 6.5V input-designed for space-constrained battery-powered systems like palmtop computers and PCMCIA cards.

For engineers reviewing the MAX8868EUK50 datasheet, MAX8868EUK50 pinout, MAX8868EUK50 application, or MAX8868EUK50 equivalent, key selection criteria include its 5.0V fixed output accuracy (±1.4%), 10nA shutdown current, SOT23-5 package compatibility, and auto-discharge functionality absent in the MAX8867 series.

Technical Context

The MAX8868EUK50 uses an internal P-channel MOSFET pass transistor (1.1Ω typical R_DS(ON)) enabling ultra-low quiescent current (100µA across all load and dropout conditions) and eliminating base-drive losses inherent in PNP-based regulators. Its error amplifier compares a 1.25V bandgap reference against feedback from an internal resistor divider tied to the OUT pin.

Unlike the MAX8867, the MAX8868EUK50 integrates active auto-discharge via an internal NMOS switch between OUT and GND during SHDN assertion, reducing output voltage to ground within microseconds. It also includes thermal shutdown (155°C trip, 15°C hysteresis), short-circuit current limiting (160–390mA), and reverse battery protection limiting reverse current to 1mA when VIN or SHDN falls below GND.

Key Specifications

Pinout & Package

SOT23-5 regular package (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm body, lead pitch 0.95mm. GND pin serves as electrical ground and primary thermal path-requires soldering to large copper area for thermal management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise LDO regulator applications.

Compared with MAX8867EUK50, the MAX8868EUK50 adds critical auto-discharge for safe power sequencing, while TCS2105-5.0 trades off noise, protection, and dropout to achieve lower unit cost-making MAX8868EUK50 the optimal choice for high-integrity battery-powered applications demanding both precision and fault resilience.

Availability

MAX8868EUK50 is available at Aetrix Electronics and suitable for palmtop computers, PCMCIA cards, and cellular telephones requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX8868EUK50 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 MAX8867/MAX8868 product line was designed specifically for battery-powered portable electronics requiring ultra-low noise, low quiescent current, and robust fault protection in minimal SOT23-5 footprint.

FAQ

What is the output voltage tolerance of the MAX8868EUK50 over temperature and load?

The MAX8868EUK50 has a guaranteed output voltage accuracy of ±1.4% over the full -40°C to +85°C operating temperature range and 0mA to 150mA load current. Typical output voltage drift versus temperature is less than ±0.5% across -40°C to +85°C at 50mA load, as confirmed by Figure MAX8867/8-08 in the datasheet. This precision eliminates need for post-production calibration in most portable applications.

Does the MAX8868EUK50 require external components for stable operation?

Yes-the MAX8868EUK50 requires three external capacitors: a ≥1µF ceramic input capacitor (CIN), a 1–10µF ceramic output capacitor (COUT) with X7R/X5R dielectric, and a 0.01µF ceramic capacitor on the BP pin. These are mandatory for stability, noise reduction, and transient response. The BP capacitor directly sets output noise performance, while COUT ESR must remain within the stable region shown in Figure MAX8867/8-17.

How does the auto-discharge function of the MAX8868EUK50 operate during shutdown?

When SHDN is pulled low, the MAX8868EUK50 activates an internal NMOS transistor between OUT and GND, creating a low-impedance discharge path. This reduces the output voltage to near ground in under 100µs (per Figure MAX8867/8-25), preventing back-powering of upstream circuitry or latch-up in downstream logic. The MAX8867EUK50 lacks this feature entirely.

What thermal considerations apply to the MAX8868EUK50 in SOT23-5 package?

The MAX8868EUK50 in SOT23-5 regular package has θ_JB = 140°C/W. To maintain junction temperature ≤150°C, the GND pin must be soldered to a minimum 100mm² copper area acting as heatsink. At 150mA load with 6.5V input (1.5V dropout), power dissipation is 225mW-requiring ambient temperature ≤70°C with proper PCB thermal design per the Absolute Maximum Ratings table.

Is the MAX8868EUK50 pin-compatible with other regulators in the same family?

Yes-the MAX8868EUK50 is pin-compatible with MAX8867EUK50, MAX8863, and MAX8864 in SOT23-5 package, sharing identical IN, GND, OUT, SHDN, and BP pin assignments. However, the BP pin function differs slightly: MAX8863/64 use BP for bias current setting, while MAX8867/68 use it for noise filtering. Always verify BP capacitor value per device family.