LinearVoltageRegulators Motorola Semiconductor Products, LinearVoltageRegulators Datasheet - Page 20

• Manufacturer Part Number: LinearVoltageRegulators
• Description: Analog And Interface Integratedcircuits Selector Guide & Cross Reference
• Manufacturer: Motorola Semiconductor Products

Step–Down Voltage Regulators
LM2575T–XX, TV, D2T, LM2576T–XX, TV, D2T
T J = –40 to +125 C, Case 314D, 314B, 936A
grated circuits ideally suited for easy and convenient design
of a step–down switching regulator (buck converter). All cir-
cuits of this series are capable of driving a 1.0 A (LM2575) or
3.0 A (LM2576) load with excellent line and load regulation.
These devices are available in fixed output voltages of 3.3 V,
5.0 V, 12 V, 15 V, and an adjustable output version.
of external components to simplify the power supply design.
Standard series of inductors optimised for use with the
LM2575/6 are offered by several different inductor manufac-
turers.
supply, its efficiency is significantly higher in comparison with
popular three–terminal linear regulators, especially with high-
er input voltages. In many cases, the power dissipated by the
LM2575/6 regulator is so low, that no heatsink is required or
its size could be reduced dramatically.
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, fea-
turing 80 A typical standby current. The output switch in-
cludes cycle–by–cycle current limiting, as well as thermal
shutdown for full protection under fault conditions.
Unregulated
ANALOG AND INTERFACE INTEGRATED CIRCUITS
SELECTOR GUIDE & CROSS REFERENCE
The LM2575/6 series of regulators are monolithic inte-
These regulators were designed to minimize the number
Since the LM2575/6 converter is a switch–mode power
The LM2575/6 features include a guaranteed 4% toler-
DC Input
C in
Feedback
+V in
1
4
R2
R1
1.0 k
Band–Gap
Reference
Representative Block Diagram and Typical Application
1.235 V
Fixed Gain
Error Amplifier
18 kHz
Freq
Shift
This device contains 162 active transistors.
(continued)
Oscillator
52 kHz
Comparator
3.1 V Internal
Regulator
Reset
Latch
Current
Features
Applications
Adjustable Output
Limit
ON/OFF
3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions
Adjustable Version Output Voltage Range of 1.23 V to
Guaranteed 1.0 A (LM2575) 3.0 A (LM2576)
Wide Input Voltage Range: 4.75 V to 40 V
Requires Only 4 External Components
52 kHz Fixed Frequency Internal Oscillator
TTL Shutdown Capability, Low Power Standby Mode
High Efficiency
Uses Readily Available Standard Inductors
Thermal Shutdown and Current Limit Protection
Simple and High–Efficiency Step–Down (Buck)
Efficient Pre–Regulator for Linear Regulators
On–Card Switching Regulators
Positive to Negative Converters (Buck–Boost)
Negative Step–Up Converters
Power Supply for Battery Chargers
37 V 4% Maximum Over Line and Load Conditions
Output Current
Regulators
XX = Voltage Option, i.e., 3.3, 5, 12, 15 V; and ADJ for
Shutdown
Driver
Thermal
1.0 Amp
Switch
ON/OFF
5
Output
2
Gnd
3
Voltage Versions
For adjustable version
R1 = open, R2 = 0
D1
Output
3.3 V
5.0 V
12 V
15 V
L1
MOTOROLA
C out
8.84 k
11.3 k
1.7 k
3.1 k
Regulated
( )
R2
Output
V out
Load
49