Analog Devices Inc./Maxim Integrated MAX8867EZK33+T

Overview

MAX8867EZK33+T from Maxim Integrated is a low-noise, low-dropout linear regulator with 3.3V preset output, 150mA output current capability, 30µVRMS output noise, and 165mV dropout at full load - designed for battery-powered handheld instruments requiring stable, clean power under light-to-moderate load.

For engineers reviewing the MAX8867EZK33+T datasheet, MAX8867EZK33+T pinout, MAX8867EZK33+T application, or MAX8867EZK33+T equivalent, key selection criteria include its thin SOT23-5 package, 10nA shutdown current, reverse battery protection, and BP-pin noise-filtering architecture for ultra-low-noise operation in space-constrained portable systems.

Technical Context

The MAX8867EZK33+T uses an internal P-channel MOSFET pass transistor (1.1Ω typical R_DS(ON)) to achieve low quiescent current (100µA across all load and dropout conditions) and eliminate 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.

Noise reduction is implemented via a dedicated BP pin connected to an internal 200kΩ resistor, forming an 80Hz low-pass filter with an external 0.01µF ceramic capacitor - enabling 30µVRMS output noise performance. Thermal shutdown activates at +155°C with 15°C hysteresis, and reverse battery protection limits reverse current to ≤1mA when VIN or SHDN falls below ground.

Key Specifications

Pinout & Package

MAX8867EZK33+T is housed in a thin 5-pin SOT23 package (JEDEC MO-178AA), with exposed pad not electrically connected - requires soldering GND pin 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 MAX8867EUK33+T, the MAX8867EZK33+T offers lower profile and better thermal resistance; compared with MCP1700T-3302E/MB, it delivers superior noise suppression and integrated reverse-battery safety at the cost of higher quiescent current and slightly larger footprint.

Availability

MAX8867EZK33+T is available at Aetrix Electronics and suitable for hand-held instruments, PCMCIA cards, palmtop computers, and electronic planners requiring stable component supply with guaranteed long-term manufacturability and consistent parametric performance.

Supply support for MAX8867EZK33+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, communications, and consumer applications.

The MAX8867/MAX8868 series was developed specifically for battery-powered portable electronics demanding ultra-low noise, minimal quiescent current, and robust fault protection in miniature packages.

FAQ

What is the output voltage tolerance of the MAX8867EZK33+T over temperature?

The MAX8867EZK33+T maintains ±1.4% output voltage accuracy across the full operating temperature range of -40°C to +85°C, as specified in the Electrical Characteristics table. This tolerance includes initial accuracy, line regulation, load regulation, and thermal drift - verified via SQC correlation methods, not just +25°C testing. The MAX8867EZK33+T achieves this using a trimmed internal resistor divider referenced to a stable 1.25V bandgap.

Does the MAX8867EZK33+T include auto-discharge functionality during shutdown?

No, the MAX8867EZK33+T does not provide auto-discharge. That feature is exclusive to the MAX8868 variant (e.g., MAX8868EZK33+T). When the SHDN pin is pulled low on the MAX8867EZK33+T, the output remains floating at its last regulated voltage; external discharge circuitry is required if rapid VOUT decay is needed. This distinction is explicitly stated in the General Description and Pin Description sections of the datasheet.

What capacitor values are recommended for stable operation of the MAX8867EZK33+T?

For stable operation, the MAX8867EZK33+T requires a minimum 1µF ceramic input capacitor (X5R/X7R dielectric) and a 1µF–10µF output capacitor with ESR ≤0.2Ω. A 0.01µF ceramic capacitor must be placed on the BP pin. Larger COUT values (e.g., 10µF) improve PSRR and load-transient response but increase start-up time. Z5U/Y5V dielectrics are discouraged due to capacitance drift at low temperatures.

Can the MAX8867EZK33+T operate with a 2.5V input while delivering 3.3V output?

No - the MAX8867EZK33+T cannot regulate 3.3V output from a 2.5V input. Its minimum input voltage is defined by VOUT + dropout voltage. At 150mA, dropout is 165mV, so minimum VIN = 3.3V + 0.165V = 3.465V. The 2.5V–6.5V input range applies only when VOUT is ≤2.5V (e.g., MAX8867EZK25+T). For 3.3V output, valid input starts at ~3.47V and extends to 6.5V.

Is the GND pin of the MAX8867EZK33+T internally connected to the die substrate?

Yes - the datasheet states "SUBSTRATE CONNECTED TO GND" in the Chip Information section. This confirms the silicon substrate is tied to the GND pin, making it essential to solder the GND pad to a large PCB ground plane not only for electrical return but also for thermal conduction and EMI shielding. Failure to do so risks thermal runaway under 150mA load in the thin SOT23 package.