Voltage Converter. BM2596 Datasheet
Step-down Voltage Converter
The BM2596(=MSP1250G) series of regulators are integrated circuits that provide all
active functions for a step-down (buck) switching regulator, capable of driving a 3A load
with excellent line and load regulation. These devices are avail-able in fixed output voltages
of 3.3V, 5V, 12V, and an adjust-able output version.
Requiring a minimum number of external components, these regulators are simple to use
www.DataSheet4U.com and include internal frequency compensation†, and a fixed-frequency oscillator.
The MSP1250G series operates at a switching frequency of 150 kHz thus allowing smaller
sized filter components than what would be needed with lower frequency switching
regulators. Available in a standard 5-lead TO-220 package with 5 pins lead in one line
options, and a 5-lead TO-263 surface mount package. A standard series of inductors are
available from several different manufacturers optimized for use with the MSP1250G series.
This feature greatly simplifies the design of switch-mode power supplies.
Other features include a guaranteed ±2% tolerance on output voltage under specified input
voltage and output load conditions, and ±10% on the oscillator frequency. External
shutdown is included, featuring typically 80 µA standby current. Self-protection features
include a two stage frequency reducing current limit for the output switch and an over tem
perature shutdown for complete protection under fault conditions.
3.3V, 5V, 12V, and adjustable output versions (ADJ)
Adjustable version output voltage range, 1.25V to 37V±2% max over line and load
Available in TO-220 and TO-263 packages
Guaranteed 3A output load current
Input voltage range up to 40V
Requires only 4 external components
Excellent line and load regulation specifications
150 kHz fixed frequency internal oscillator
TTL shutdown capability
Low power standby mode, IQ typically 80 µA
G means Pb free in MSP1250G
Uses readily available standard inductors
Thermal shutdown and current limit protection
Simple high-efficiency step-down (buck) regulator , CAR DVD electronic
On-card switching regulators , LCD-TV , LCD-monitor , ADSL
Positive to negative converter
5-Lead TO-220 (T)
Step-down Voltage Converter
5-Lead TO-263 (S)
12 3 4 5
+VIN —This is the positive input supply for the IC switching regulator. A suitable input
bypass capacitor must be present at this pin to minimize voltage transients and to supply
the switching currents needed by the regulator.
Ground —Circuit ground.
Output —Internal switch. The voltage at this pin switches between (+VIN - VSAT) and
approximately -0.5V, with a duty cycle of approximately VOUT/VIN. To minimize coupling to
sensitive circuitry, the PC board copper area connected to this pin should be kept to a
FeedBack —Senses the regulated output voltage to complete the feedback loop.
—Allows the switching regulator circuit to be shut down using logic level signals
thus dropping the total input supply current to approximately 80 µA. Pulling this pin below
a threshold voltage of approximately 1.3V turns the regulator on, and pulling this pin above
1.3V (up to a maximum of 25V) shuts the regulator down. If this shutdown feature is not
pin can be wired to the ground pin or it can be left open, in either
case the regulator will be in the ON condition.
Marking information: BM2596 -xx or MSP1250G -xx on the chip, both two numbers are Pb-free;
xx means output voltage