Microchip Technology MIC5399-SSYMX-T5

Overview

MIC5399-SSYMX-T5 from Microchip Technology is a dual low-dropout linear regulator IC delivering two independent 300 mA outputs at fixed 3.3V/3.3V, operating from 2.5V to 5.5V input. It features ±2% output accuracy, 160 mV dropout at full load, and integrated output discharge circuitry and enable pull-down resistors-designed for power sequencing in compact portable electronics.

For engineers reviewing the MIC5399-SSYMX-T5 datasheet, MIC5399-SSYMX-T5 pinout, MIC5399-SSYMX-T5 application, or MIC5399-SSYMX-T5 equivalent, key selection criteria include dual-rail stability with 1 µF ceramic capacitors, zero-off-state shutdown current (0.05 µA), thermal shutdown protection, and compatibility with space-constrained 1.6 mm × 1.2 mm Extra Thin DFN packaging.

Technical Context

The MIC5399-SSYMX-T5 implements two fully independent LDO regulators sharing no internal bias or reference paths, enabling separate VIN1/VIN2 inputs and EN1/EN2 controls. Each channel supports 1V–3.3V output range (this variant fixed at 3.3V/3.3V), with fast transient response and 60 dB PSRR at 1 kHz.

It integrates dual functional enhancements over base family members: an auto-discharge NFET (25 Ω) activated on disable for rapid VOUT1/VOUT2 capacitor discharge, and internal 4 MΩ enable pull-down resistors ensuring reliable off-state when EN pins are tri-stated-critical for systems with uncontrolled GPIO states.

Key Specifications

Pinout & Package

Package: 8-Lead Extra Thin DFN (X2DFN), 1.6 mm × 1.2 mm × 0.35 mm body, exposed thermal pad (ePad) requiring PCB ground connection for thermal performance and EMI reduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MIC5399-SMYMX-T5, the MIC5399-SSYMX-T5 delivers matched 3.3V rails ideal for symmetric subsystems, while TPL7407LPGEDR lacks dual outputs and critical safety features-making MIC5399-SSYMX-T5 the sole fit for true dual-rail, low-leakage, discharge-capable portable power management.

Availability

MIC5399-SSYMX-T5 is available at Aetrix Electronics and suitable for smartphone power management, portable medical sensor hubs, industrial handheld terminals, and wearable fitness trackers requiring stable component supply across high-mix, low-volume production runs.

Supply support for MIC5399-SSYMX-T5 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

Microchip Technology Inc. is a leading provider of microcontroller, analog, FPGA, and mixed-signal semiconductors, serving automotive, industrial, consumer, and communications markets with vertically integrated design and manufacturing.

The MIC5399 belongs to Microchip's low-power dual LDO product line, engineered specifically for space- and power-constrained portable electronics requiring independent, fast-turning, and safely discharged dual voltage rails.

FAQ

What output voltages does the MIC5399-SSYMX-T5 provide?

The MIC5399-SSYMX-T5 provides two fixed 3.3V outputs-VOUT1 = 3.3V and VOUT2 = 3.3V-as indicated by the "SS" voltage option code in the part number. This configuration eliminates external feedback networks and simplifies design for symmetric dual-rail applications such as powering paired communication interfaces or redundant sensor chains. The device maintains ±2% accuracy across –40°C to +125°C.

Does the MIC5399-SSYMX-T5 include output discharge functionality?

Yes, the MIC5399-SSYMX-T5 includes an integrated output discharge circuit on both VOUT1 and VOUT2. When either EN1 or EN2 is driven low, a 25 Ω internal NFET connects the respective output to GND, actively discharging external capacitors. This feature prevents back-powering of upstream circuitry and ensures clean power-down sequencing-critical in battery-operated systems where residual voltage can cause latch-up or data corruption.

What is the package type and thermal pad requirement for MIC5399-SSYMX-T5?

The MIC5399-SSYMX-T5 uses an 8-lead Extra Thin DFN (X2DFN) package measuring 1.6 mm × 1.2 mm × 0.35 mm, with an exposed thermal pad (ePad) on the bottom. The ePad must be soldered to a dedicated PCB ground plane using at least four thermal vias (0.3 mm diameter, filled/tented) to maintain junction temperature below 125°C under full 300 mA load per channel. Failure to connect the ePad degrades thermal performance and may trigger premature thermal shutdown.

Can MIC5399-SSYMX-T5 operate with only 1 µF output capacitors?

Yes, the MIC5399-SSYMX-T5 is explicitly designed and characterized for stability with ≥1 µF ceramic output capacitors-no additional bulk capacitance required. X5R or X7R dielectric types are recommended for optimal temperature stability; Y5V dielectrics are not advised due to >60% capacitance loss over temperature. This 1 µF requirement reduces bill-of-materials cost and PCB area versus legacy LDOs needing 10–22 µF tantalum or aluminum electrolytic capacitors.

What is the shutdown current specification for MIC5399-SSYMX-T5?

The MIC5399-SSYMX-T5 draws only 0.05 µA (typical) when both EN1 and EN2 are held low-enabling ultra-low-power deep-sleep modes in portable electronics. This near-zero shutdown current is achieved via internal CMOS gate control and is validated across –40°C to +125°C. In comparison, many dual-LDOs draw >1 µA in shutdown, making MIC5399-SSYMX-T5 especially valuable for battery-powered devices requiring multi-month shelf life or extended operational runtime between charges.