MIC4574 Micrel, Inc. MIC4574
200kHz Simple 0.5A Buck Regulator General Description Features The MIC4574 is a series of easy to use fixed and adjustable
BiCMOS step-down (buck) switch-mode voltage regulators.
The 200kHz MIC4574 duplicates the pinout and function of
the 52kHz LM2574. The higher switching frequency may
allow up to a 2:1 reduction in output filter inductor size.
The MIC4574 is available in 3.3V, and 5V fixed output
versions or a 1.23V to 20V adjustable output version. Both
versions are capable of driving a 0.5A load with excellent line
and load regulation.
The feedback voltage is guaranteed to В±2% tolerance for
adjustable versions, and the output voltage is guaranteed to
В±3% for fixed versions, within specified voltages and load
conditions. The oscillator frequency is guaranteed to В±10%.
In shutdown mode, the regulator draws less than 200ВµA
standby current. The regulator performs cycle-by-cycle current limiting and thermal shutdown for protection under fault
conditions.
This series of simple switch-mode regulators requires a
minimum number of external components and can operate
using a standard series of inductors. Frequency compensation is provided internally. Fixed 200kHz operation 3.3V, 5V, and adjustable output versions Voltage over specified line and load conditions:
Fixed version: В±3% max. output voltage
Adjustable version: В±2% max. feedback voltage Guaranteed 0.5A switch current Wide 4V to 24V input voltage range Wide 1.23V to 20V output voltage range Requires minimum external components < 200ВµA typical shutdown mode 75% efficiency (adjustable version > 75% typ.) Standard inductors and capacitors are
25% of typical LM2574 values Thermal shutdown Overcurrent protection 100% electrical thermal limit burn-in Applications Simple high-efficiency step-down (buck) regulator …
