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MIC3172

1.25A 100kHz Switching Regulator

Status: In Production

Features:

  • 1.25A, 65V internal switch rating
  • 3V to 40V input voltage range
  • Current-mode operation
  • Internal cycle-by-cycle current limit
  • Thermal shutdown
  • Low external parts count
  • Operates in most switching topologies
  • 7mA quiescent current (operating)
  • <1µA quiescent current, shutdown mode (MIC3172)
  • TTL shutdown compatibility (MIC3172)
  • External frequency synchronization (MIC2172)
  • External frequency trim (MIC2172)
  • Fits most LT1172 sockets (see applications info)
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Overview
Documents
Development Environment
RoHS Information
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Device Overview

Summary

The MIC2172 and MIC3172 are complete 100kHz SMPS current-mode controllers with internal 65V 1.25A power switches. The MIC2172 features external frequency synchronization or frequency adjustment, while the MIC3172 features an enable/shutdown control input.

Although primarily intended for voltage step-up applications, the floating switch architecture of the MIC2172/3172 makes it practical for step-down, inverting, and Cuk configurations as well as isolated topologies.

Operating from 3V to 40V, the MIC2172/3172 draws only 7mA of quiescent current making it attractive for battery operated supplies.

The MIC3172 is for applications that require on/off control of the regulator. The MIC3172 is externally shutdown by applying a TTL low signal to EN (enable). When disabled, the MIC3172 draws only leakage current (typically less than 1µA). EN must be high for normal operation. For applications not requiring control, EN must be tied to VIN or TTL high.

The MIC2172 is for applications requiring two or more SMPS regulators that operate from the same input supply. The MIC2172 features a SYNC input which allows locking of its internal oscillator to an external reference. This makes it possible to avoid the audible beat frequencies that result from the unequal oscillator frequencies of independent SMPS regulators.

A reference signal can be supplied by one MIC2172 designated as a master. To insure locking of the slave's oscillators, the reference oscillator frequency must be higher than the slave's. The master MIC2172's oscillator frequency is increased up to 135kHz by connecting a resistor from SYNC to ground (see applications information).

The MIC2172/3172 is available in an 8-pin plastic DIP or SOIC for -40°C to +85°C operation.

Additional Features
    • 1.25A, 65V internal switch rating
    • 3V to 40V input voltage range
    • Current-mode operation
    • Internal cycle-by-cycle current limit
    • Thermal shutdown
    • Low external parts count
    • Operates in most switching topologies
    • 7mA quiescent current (operating)
    • <1µA quiescent current, shutdown mode (MIC3172)
    • TTL shutdown compatibility (MIC3172)
    • External frequency synchronization (MIC2172)
    • External frequency trim (MIC2172)
    • Fits most LT1172 sockets (see applications info)
Parametrics
Name
Value
Regulator Type
Step Up (Boost)
Input Voltage Range Min (V)
3
Input Voltage Range Max (V)
40
Output Voltage Range Min (V)
3.6
Output Voltage Range Max (V)
65
Output Current (mA) max
1250
Quiescent Current (mA) typ
7
Switching Frequency (kHz)
100
Operating Temp Range
-40 to 85
Vfb (V)
1.24
Duty Cycle Max (%)
95
SHUTDOWN Current (µA) (Typ)
0.1
Switch current (A) typ
1.25
Alternative Topology
SEPIC, CUK, Flyback

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RoHS Information

Part Number
Device Weight (g)
Shipping Weight (grams)
Lead Count
Package Type
Package Width
Solder Composition
JEDEC Indicator
RoHS
China EFUP
MIC3172YM
0.075000
0.163265
8
SOIC
3.90mm(.150in)
NiPdAu
e4
MIC3172YM-TR
0.075000
0.250000
8
SOIC
3.90mm(.150in)
NiPdAu
e4
MIC3172YN
0.486700
0.900000
8
PDIP
.300in
Matte Tin
e3
To see a complete listing of RoHS data for this device, please Click here
Shipping Weight = Device Weight + Packing Material weight. Please contact sales office if device weight is not available.

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