TC2574 Datasheet, PDF (1/25 Pages) TelCom Semiconductor, Inc – 0.5A Step-Down Switching Regulator

0.5A Step-Down Switching Regulator
T_TC_C2₂5₅7₇4
0.5A Step-Down Switching Regulator
FEATURES
s 3.3V, 5.0V, 12V and Adjustable Output Versions
s Adjustable Version Output Voltage Range,
1.23 to 37 V ±4% Max Over Line and Load Conditions
s Guaranteed 0.5 A Output Current
s Wide Input Voltage Range: 4.75 to 40V
s Requires Only 4 External Components
s 52kHz Fixed Frequency Internal Oscillator
s TTL Shutdown Capability, Low Power Standby Mode
s High Efficiency
s Uses Readily Available Standard Inductors
s Thermal Shutdown and Current Limit Protection
APPLICATIONS
s Simple and High–Efficiency Step–Down (Buck)
Regulator
s Efficient Pre-Regulator for Linear Regulators
s On–Card Switching Regulators
s Positive to Negative Converters (Buck–Boost)
s Negative Step-Up Converters
s Power Supply for Battery Chargers
PIN CONFIGURATIONS
16-Pin SOIC (Wide)
NC ₁
NC 2
FB 3
SIG GND 4
ON/OFF 5
PWR GND ₆
NC 7
NC 8
TC2574
16 _NC
15 NC
14 OUTPUT
13 NC
12 VIN
11 NC
10 NC
9 NC
8-Pin PDIP (Narrow)
FB ₁
SIG GND 2
ON/OFF 3
PWR GND 4
TC2574
8 NC
7 OUTPUT
6 NC
5 VIN
GENERAL DESCRIPTION
The TC2574 series of regulators are monolithic inte-
grated circuits ideally suited for easy and convenient design
of a step-down switching regulator (buck converter). All
circuits of this series are capable of driving a 0.5A load with
excellent line and load regulation. These devices are avail-
able in fixed output voltages of 3.3V, 5.0V, 12V and
an adjustable output version.
These regulators were designed to minimize the num-
ber of external components to simplify the power supply
design. Standard series of inductors optimized for use with
the TC2574 are offered by several different inductor manu-
facturers.
Since the TC2574 converter is a switch–mode power
supply, its efficiency is significantly higher in comparison
with popular three-terminal linear regulators, especially with
higher input voltages. In most cases, the power dissipated
by the TC2574 regulator is so low, that the copper traces on
the printed circuit board are normally the only heatsink
needed and no additional heatsinking is required.
The TC2574 features include a guaranteed ±4% toler-
ance on output voltage within specified input voltages and
output load conditions, and ±10% on the oscillator frequency
(±2% over 0°C to +125°C). External shutdown is included,
featuring 60µA (typical) standby current. The output switch
includes cycle–by–cycle current limiting, as well as thermal
shutdown for full protection under fault conditions.
ORDERING INFORMATION
Part
Number
Package
Temperature
Range
TC2574-3.3VPA
TC2574-5.0VPA
TC2574-12.0VPA
TC2574-VPA*
TC2574-VOE*
8-Pin PDIP (Narrow) –40 to +125°C
8-Pin PDIP (Narrow) –40 to +125°C
8-Pin PDIP (Narrow) –40 to +125°C
8-Pin PDIP (Narrow) –40 to +125°C
16-Pin SOIC (Wide) –40 to +125°C
Note: *ADJ = 1.23 To 37V.
TC2574-1 1/6/00 TelCom Semiconductor reserves the right to make changes in the circuitry an1d specifications of its devices.