Microchip Technology MIC94355-4YCS-TR Overview

The MIC94355-4YCS-TR is an advanced active noise suppression device designed by Microchip Technology. It incorporates Microchip's Ripple Blocker™ technology, offering high-performance power supply filtering by attenuating noise and ripple from DC power lines without the need for bulky external components. It is especially valuable in modern portable electronics, RF systems, camera modules, and sensitive analog applications where power integrity is critical.

This device acts as a low-dropout regulator-like filter, effectively isolating downstream circuitry from upstream power supply noise without regulating voltage. Unlike traditional passive LC filters, the MIC94355 provides superior noise rejection in a much smaller footprint.

Core Functionality

* Function Type: Active noise suppression / ripple blocker
* Technology: Proprietary Ripple Blocker™ filtering
* Application: Point-of-load noise attenuation in low-noise analog and RF systems

Key Electrical Specifications

* Input Voltage Range: 1.8V to 5.5V
* Output Voltage Range: 1.8V to 5.5V (same as input, as it’s not a regulator)
* Output Current Capability: Up to 500 mA continuous
* Quiescent Current (I\_Q): Typically 65 µA (very low, suitable for portable systems)
* Shutdown Current: <1 µA (ultra-low for efficient standby operation)
* Dropout Voltage: Typically 65 mV at 500 mA load (extremely low for minimal voltage loss)
* Power Supply Rejection Ratio (PSRR):

* 35 dB at 1 MHz
* 60 dB at 100 kHz (typical values; excellent suppression of high-frequency noise)

Performance and Noise Filtering

* Ripple Rejection Mechanism: Filters both high-frequency switching noise and low-frequency ripple originating from DC/DC converters or switching regulators
* Transient Response: Fast response to load changes; maintains noise attenuation during dynamic current demand
* Noise Isolation: Effectively protects downstream analog or RF circuits from upstream digital switching noise or ripple

Control and Enable Functions

* Enable Pin (EN): Logic-controlled shutdown pin

* Logic High: Device enabled
* Logic Low: Device enters ultra-low power shutdown
* Turn-On Time: ~50 µs (fast response suitable for time-sensitive applications)

Thermal and Protection Features

* Short-Circuit Protection: Yes
* Thermal Shutdown: Integrated for safe operation in case of overheating
* Output Discharge: Automatic discharge of output when disabled
* Thermal Resistance (Junction to Ambient): ~220°C/W (in standard PCB layout)

Package and Physical Characteristics

* Package Type: 4-pin SC-70 (also known as YCS)
* Package Code: SC70-4L
* Mounting Type: Surface Mount Technology (SMT)
* Dimensions:

* Approx. 2.0 mm × 2.1 mm footprint
* Ultra-small, optimized for dense PCB layouts
* Tape and Reel Packaging: Yes (TR suffix), suited for automated pick-and-place machines

Operating Conditions

* Operating Temperature Range: -40°C to +125°C (Automotive/Industrial grade)
* ESD Protection: Integrated ESD protection on all pins
* RoHS and REACH Compliance: Fully compliant for environmentally friendly design

Applications

* RF Systems: Excellent for use between power regulators and RF transceivers or amplifiers
* Camera Modules and Image Sensors: Prevents power ripple from degrading image quality
* Audio Systems: Isolates sensitive analog audio circuits from noisy power rails
* Wireless Modules: Helps stabilize power to Bluetooth, Wi-Fi, Zigbee, or LTE modules
* Wearables and IoT Devices: Provides compact, low-power noise filtering in space-limited designs
* Medical and Industrial Sensors: Enhances signal integrity in analog front-end circuits

Comparison with Passive Filtering

* Size Advantage: Requires no bulky inductors or capacitors
* Performance Advantage: Better high-frequency rejection than typical LC filters
* Power Efficiency: Minimal voltage drop and low quiescent current
* Integration: Single-chip solution simplifies BOM and PCB routing

Summary

The MIC94355-4YCS-TR is a highly efficient, compact, and low-power active noise filter ideal for high-performance, noise-sensitive systems. With Microchip’s Ripple Blocker™ technology, it achieves excellent noise suppression without large passive components. Its ability to support up to 500 mA with minimal dropout and excellent PSRR makes it a superior choice over traditional LC filters in RF, audio, imaging, and precision analog applications. Designed for modern portable and embedded systems, it significantly improves power integrity while occupying minimal board space.