Analog Devices Inc./Maxim Integrated MAX8559ETA11+

Overview

MAX8559ETA11+ from Maxim Integrated is a dual, low-noise, low-dropout linear regulator delivering two independent 1.85V outputs at up to 300mA each, operating from 2.5V–6.5V input. It features 32µVRMS output noise, 70dB PSRR at 10kHz, and 60mV dropout at 100mA load-designed for space-constrained, battery-powered systems requiring clean, stable dual-rail power.

For engineers reviewing the MAX8559ETA11+ datasheet, MAX8559ETA11+ pinout, MAX8559ETA11+ application, or MAX8559ETA11+ equivalent, key selection criteria include factory-preset 1.85V/1.85V dual outputs, independent logic-controlled shutdown (SHDNA/SHDNB), ultra-low 115µA per-LDO quiescent current, and compatibility with small ceramic capacitors without mandatory bypass.

Technical Context

The MAX8559ETA11+ integrates two independent P-channel MOSFET pass transistors (R_DS(ON) ≈ 0.6Ω) with internal 1.25V bandgap reference and error amplifiers, enabling precise feedback control without external resistors. Each LDO uses an internal voltage divider to set its fixed 1.85V output, eliminating external resistor networks and reducing layout sensitivity.

Its shutdown architecture supports three operational states: individual LDO disable (via SHDNA or SHDNB), full chip disable (both inputs low, reducing supply current to 0.01µA), and always-on configuration (inputs tied to INA/INB). Thermal protection activates at +160°C with 10°C hysteresis, and each output includes autonomous current limiting (310mA min) and internal 385Ω discharge path during shutdown.

Key Specifications

Pinout & Package

MAX8559ETA11+ is packaged in an 8-pin TDFN-EP (3mm × 3mm, 0.8mm height) with exposed thermal pad. The package supports high-power dissipation (1.95W) and requires soldering the exposed pad to PCB ground plane for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-LDO applications.

Compared with TPS7A202828DQNR and MCP1826S-1818KE/AB, MAX8559ETA11+ uniquely delivers factory-set 1.85V/1.85V outputs with true per-LDO shutdown, sub-32µVRMS noise, and 60mV dropout-making it optimal for battery-powered dual-rail systems demanding precision, low noise, and flexible power sequencing.

Availability

MAX8559ETA11+ is available at Aetrix Electronics and suitable for cellular handsets, digital cameras, notebook subsystems, and wireless LAN cards requiring stable component supply, long-lifecycle support, and lead-free compliance.

Supply support for MAX8559ETA11+ 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 high-reliability industrial, automotive, and portable applications.

The MAX8559 belongs to Maxim's low-noise, dual-LDO product line engineered specifically for battery-powered portable electronics needing compact, efficient, and independently controllable dual-rail regulation.

FAQ

What output voltages does the MAX8559ETA11+ provide?

The MAX8559ETA11+ provides two factory-preset 1.85V outputs (VOUTA = VOUTB = 1.85V), selected by the "11" suffix in the part number per Maxim's Output Voltage Selector Guide. These outputs are fixed and require no external resistors. The MAX8559ETA11+ maintains ±3% accuracy over -40°C to +85°C and load currents from 0.1mA to 300mA, making it ideal for applications requiring tight voltage tolerance without trimming components.

Does the MAX8559ETA11+ require an external bypass capacitor on the BP pin?

The MAX8559ETA11+ does not require an external capacitor on the BP pin for basic operation, but adding a 0.01µF low-leakage ceramic capacitor reduces output noise to 32µVRMS (100Hz–100kHz). Without it, noise rises to 254µVRMS. The BP capacitor is optional and used only when ultra-low noise is critical-such as powering analog sensors or RF sections. Its omission simplifies the design and reduces BOM count for less sensitive digital loads.

What is the maximum continuous output current per channel for the MAX8559ETA11+?

The MAX8559ETA11+ delivers up to 300mA continuous output current per channel (OUTA and OUTB), provided the output capacitors are ≥4.7µF ceramic and thermal limits are observed. At 100mA load, dropout is 60mV; at full 300mA, dropout increases proportionally based on R_DS(ON). The TDFN package supports 1.95W power dissipation, allowing safe operation under worst-case VIN = 6.5V, VOUT = 1.85V, and IOUT = 300mA conditions when the exposed pad is properly soldered to the PCB ground plane.

How does the shutdown functionality work on the MAX8559ETA11+?

The MAX8559ETA11+ features two independent shutdown inputs: SHDNA controls OUTA, and SHDNB controls OUTB. Driving either input low disables its respective LDO and activates a 385Ω internal discharge path to pull the output to GND. Driving both inputs low shuts down the entire device-including the internal reference-reducing total supply current to 0.01µA. This enables fine-grained power management: for example, keeping OUTA active for real-time clock while shutting down OUTB for display backlight during sleep mode.

Can the MAX8559ETA11+ operate from a single-cell Li-ion battery throughout its discharge curve?

Yes-the MAX8559ETA11+ operates from 2.5V to 6.5V input and achieves only 60mV dropout at 100mA, enabling reliable regulation down to ~1.95V output with 2.01V input. Since a single-cell Li-ion battery discharges from 4.2V to ~2.8V (cutoff), the MAX8559ETA11+ remains functional across >95% of the battery's usable voltage range. Its 115µA per-LDO quiescent current further extends runtime in standby, and thermal shutdown at +160°C protects against overheating during high-current bursts.