text.skipToContent text.skipToNavigation

Manufacturer Part #


MIC38HC45 Series 6 mA 500 kHz SMT BiCMOS Current-Mode PWM Controller - SOIC-8

Mfr. Name: Microchip
Standard Pkg:
Product Variant Information section
Date Code: 1712
Product Specification Section
Technical Attributes
Attributes Table
Supply Current-Max: 6mA
Supply Voltage: 7.6V to 20V
Frequency-Max: 500kHz
Input Voltage: 2.58V
Topology: Buck/Boost/Flyback/Forward
Duty Cycle-Min: 0%
Duty Cycle-Max: 50%
Storage Temperature Range: -65°C to +150°C
Output Current: 1A
Thermal Resistance: 170°C/W
Package Style:  SOIC-8
Mounting Method: Surface Mount
Features & Applications

The MIC38HC45YM is a fixed frequency current-mode PWM controller with 1 A drive current capability. Micrel’s BiCMOS devices are pin-compatible with 384x bipolar devices. Their high output drive, with fast rise and fall times, combined with low startup current make it an ideal PWM controller where high efficiency is required.

Undervoltage lockout circuitry allows the ’42 and ’44 versions to start up at 14.5 V and operate down to 9 V, and the ’43 and ’45 versions start at 8.4 V with operation down to 7.6 V. All versions operate up to 20 V. When compared to bipolar UC384x devices operating from a 15 V supply, start-up current has been reduced to 50 μA typical and operating current has been reduced to 4.0 mA typical. Decreased output rise and fall times drive larger MOSFETs, and rail-to-rail output capability increases efficiency, especially at lower supply voltages. The MIC38HC45YM also features a trimmed oscillator discharge current and bandgap reference.
MIC38HC4x-1 is available in 14-pin plastic DIP and SOIC packages. 8-pin devices feature small size, while 14-pin devices separate the analog and power connections for improved performance and power dissipation.

Key Features:

  • Fast 20 ns output rise and 15 ns output fall times.
  • –40°C to +85°C temperature range. exceeds UC284x specifications.
  • High-performance, low-power BiCMOS Process.
  • Ultralow start-up current (50 μA typical).
  • Low operating current (4 mA typical).
  • High output drive (1 A peak current, HC version).
  • CMOS outputs with rail-to-rail swing.
  • Current-mode operation up to 500 kHz.
  • Trimmed 5 V bandgap reference.
  • Pin-for-pin compatible with UC3842/3843/3844/3845(A).
  • Trimmed oscillator discharge current.
  • UVLO with hysteresis.
  • Low cross-conduction currents.


  • Current-mode, off-line, switched-mode power supplies.
  • Current-mode, dc-to-dc converters.
  • Step-down “buck” regulators.
  • Step-up “boost” regulators.
  • Flyback, isolated regulators.
  • Forward converters
Pricing Section
Minimum Order:
Multiple Of:
On Order:
Factory Stock:Factory Stock:
Factory Lead Time:
12 Weeks
Web Price
Product Variant Information section