General Description
The MIC5321 is a tiny, dual ultra-low dropout linear
regulator ideally suited for applications that require high
PSRR because it provides a bypass pin for those noise
sensitive portable electronics. The MIC5321 integrates
two high-performance 150 mA ULDOs into a very
compact 1.6 mm x 1.6 mm leadless UDFN package
that provides exceptional thermal package
characteristics.
The MIC5321 is a μCap design that enables operation
with very small ceramic output capacitors for stability,
thereby reducing required board space and component
cost. The combination of extremely low dropout
voltage, very high power supply rejection, very low
output noise, and exceptional thermal package
characteristics makes it ideal for powering RF
application, cellular phone camera modules, imaging
sensors for digital still cameras, PDAs, MP3 players
and WebCam applications.
The MIC5321 is available in fixed-output voltages in the
tiny 6-pin 1.6 mm x 1.6 mm leadless UDFN package,
which is only 2.56 mm2 in area, less than 30% the area
of the SOT-23 and TSOP 3x3 packages. It’s also
available in the thin SOT-23 6-lead package and the
standard size 6-pin 1.6 mm x 1.6 mm leadless WDFN
package. Additional voltage options are available. For
more information, contact Microchip.

Features
• 2.3V to 5.5V Input Voltage Range
• Ultra-Low Dropout Voltage 35 mV @ 150 mA
• Tiny 6-Pin 1.6 mm x 1.6 mm Thin UDFN Leadless
Package
• Low Cost 6-Lead TSOT-23 Package
• Bypass Pin for Improved Noise Performance
• High PSRR: >75 dB on Each LDO
• Ultra-Low Noise Output: >30 μVRMS
• Dual 150 mA Outputs
• μCap Stable with 1 μF Ceramic Capacitor
• Low Quiescent Current: 150 μA
• Fast Turn-On Time: 45 μs
• Thermal Shutdown Protection
• Current Limit Protection

Applications
• Mobile Phones
• PDAs
• GPS Receivers
• Portable Electronics
• Portable Media Players
• Digital Still and Video Cameras