TECHNICAL DATA
3.0 A, 15 V, Step-Down
IL2576
Switching Regulator
The IL2576 series of regulators are monolithic integrated circuits
ideally suited for easy and convenient design of a stepdown
switching regulator (buck converter). All circuits of this series are
capable of driving a 3.0 A 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. These
regulators were designed to minimize the number of external
components to simplify the power supply design. Standard series
of inductors optimized for use with the IL2576 are offered by
several different inductor manufacturers. Since the IL2576
converter is a switchmode power supply, its efficiency is
significantly higher in comparison with popular threeterminal
linear regulators, especially with higher input voltages. In many
cases, the power dissipated is so low that no heatsink is required
or its size could be reduced dramatically. A standard series of
inductors optimized for use with the IL2576 are available from
several different manufacturers. This feature greatly simplifies the
design of switchmode power supplies. The IL2576 features
include a guaranteed 4% tolerance on output voltage within
specified input voltages and output load conditions, and 10% on
the oscillator frequency (2% over 0C to 125C). External
shutdown is included, featuring 80 A (typical) standby current.
The output switch includes cyclebycycle current limiting, as well
as thermal shutdown for full protection under fault conditions.
ORDERING INFORMATION
IL2576Q
TO-220
IL2576S
TO-220
T
A
= -40
to 125 C for all packages
S Suffix
TO-220
Q Suffix
TO-220
Heatsink
surface
connected to
Pin 3
Pin connections
1. Vin
2. Output
3. Ground
4. Feedback
5. ON/OFF
Features
3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions
Adjustable Version Output Voltage Range, 1.23 to 37 V 4%
Maximum Over Line and Load Conditions
Guaranteed 3.0 A Output Current
Wide Input Voltage Range
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
Applications
Simple HighEfficiency StepDown (Buck) Regulator
Efficient PreRegulator for Linear Regulators
OnCard Switching Regulators
Positive to Negative Converter (BuckBoost)
Negative StepUp Converters
Power Supply for Battery Chargers
1
IL2576
Typical Application (Fixed Output Voltage Versions)
Representative Block Diagram and Typical Application
This device contains 162 active transistors.
ABSOLUTE MAXIMUM RATINGS
(Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.)
Rating
Symbol
Value
Unit
Maximum Supply Voltage
Vin
45
V
ON/OFF Pin Input Voltage
0.3 V
V +Vin
V
Output Voltage to Ground (SteadyState)
1.0
V
Power Dissipation
Case 314B and 314D (TO220, 5Lead)
Thermal Resistance, JunctiontoAmbient
Thermal Resistance, JunctiontoCase
Case 936A (D2PAK)
Thermal Resistance, JunctiontoAmbient
Thermal Resistance, JunctiontoCase
PD
RJA
RJC
PD
RJA
RJC
Internally Limited
65
5.0
Internally Limited
70
5.0
W
C/W
C/W
W
C/W
C/W
Storage Temperature Range
Tstg
65 to +150
C
Minimum ESD Rating (Human Body Model:
C = 100 pF, R = 1.5 k)
2.0 kV
Lead Temperature (Soldering, 10 seconds)
260
C
2
IL2576
Maximum Junction Temperature
TJ
150
C
OPERATING RATINGS
(Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee
specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.)
Rating
Symbol
Value
Unit
Operating Junction Temperature Range
TJ
40 to +125
C
Supply Voltage
Vin
40
V
SYSTEM PARAMETERS
[Note 1]
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, V
in
= 12 V for the 3.3 V, 5.0 V, and Adjustable version, V
in
= 25 V for the 12 V version, and V
in
= 30 V for
the 15 V version. I
Load
= 500 mA, T
J
= 25C, for min/max values T
J
is the operating junction temperature range that applies [Note 2],
unless otherwise noted.)
Characteristics
Symbol
Min
Max
Unit
IL25763.3
([Note 1] Test Circuit Figure 15)
Output Voltage
Vout
3.234
3.366
V
Output Voltage (6.0 V
Vin 40 V, 0.5 A ILoad 3.0 A)
TJ = 25C
TJ = 40 to +125C
Vout
3.168
3.135
3.432
3.465
V
Efficiency (Vin = 12 V, ILoad = 3.0 A)
- - %
IL25765
[Note 1]
Output Voltage
Vout
4.9
5.1
V
Output Voltage (6.0 V
Vin 40 V, 0.5 A ILoad 3.0 A)
TJ = 25C
TJ = 40 to +125C
Vout
4.8
4.75
5.2
5.25
V
Efficiency (Vin = 12 V, ILoad = 3.0 A)
- - %
IL257612
[Note 1]
Output Voltage
Vout
11.76
12.24
V
Output Voltage (15.0 V
Vin 40 V, 0.5 A ILoad 3.0 A)
TJ = 25C
TJ = 40 to +125C
Vout
11.52
11.4
12.48
12.6
V
Efficiency (Vin = 12 V, ILoad = 3.0 A)
- - %
IL257615
[Note 1]
Output Voltage
Vout
14.7
15.3
V
Output Voltage (18 V
Vin 40 V, 0.5 A ILoad 3.0 A)
TJ = 25C
TJ = 40 to +125C
Vout
14.4
14.25
15.6
15.75
V
Efficiency (Vin = 12 V, ILoad = 3.0 A)
- - %
IL2576 ADJUSTABLE VERSION
[Note 1]
Feedback Voltage (Vin = 12 V, ILoad = 0.5 A, Vout = 5.0 V,
TJ = 25C)
Vout 1.217 1.243
V
Feedback Voltage (8.0 V
Vin 40 V, 0.5 A ILoad 3.0 A,
Vout = 5.0 V)
TJ = 25C
TJ = 40 to +125C
Vout
1.193
1.18
1.267
1.28
V
Efficiency (Vin = 12 V, ILoad = 3.0 A, Vout = 5.0 V)
- - %
1. External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system
performance.
When the IL2576 is used as shown in the test circuit, system performance will be as shown in system parameters section .
2. Tested junction temperature range for the IL2576: T
low
= 40C T
high
= +125C
3
IL2576
DEVICE PARAMETERS
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, V
in
= 12 V for the 3.3 V, 5.0 V, and Adjustable version, V
in
= 25 V
for the 12 V version, and V
in
= 30 V for the 15 V version. I
Load
= 500 mA, T
J
= 25C, for min/max values T
J
is the
operating junction temperature range that applies [Note 2], unless otherwise noted.)
Characteristics
Symbol
Min
Max
Unit
ALL OUTPUT VOLTAGE VERSIONS
Feedback Bias Current (Vout = 5.0 V [Adjustable Version
Only])
TJ = 25C
TJ = 40 to +125C
Ib
100
500
nA
Oscillator Frequency [Note 3]
TJ = 25C
TJ = 40 to +125C
fosc
42
63
kHz
Saturation Voltage (Iout = 3.0 A [Note 4])
TJ = 25C
TJ = 40 to +125C
Vsat
1.8
2.0
V
Max Duty Cycle ("on") [Note 5]
DC
93
%
Current Limit (Peak Current [Notes 3 and 4])
TJ = 25C
TJ = 40 to +125C
ICL
4.2
3.5
6.9
7.5
A
Output Leakage Current [Notes 6 and 7], TJ = 25C
Output = 0 V
Output = 1.0 V
IL
2.0
30
mA
Quiescent Current [Note 6]
TJ = 25C
TJ = 40 to +125C
IQ
10
11
mA
Standby Quiescent Current (ON/OFF Pin = 5.0 V ("off"))
TJ = 25C
Istby
200
A
ON/OFF Pin Logic Input Level
Vout = 0 V
TJ = 25C
TJ = 40 to +125C
Vout = Nominal Output Voltage
TJ = 25C
TJ = 40 to +125C
VIH
VIL
2.2
2.4
1.0
0.8
V
ON/OFF Pin Input Current
ON/OFF Pin = 5.0 V ("off"), TJ = 25C
ON/OFF Pin = 0 V ("on"), TJ = 25C
IIH
IIL
30
1.0
A
3. The oscillator frequency reduces to approximately 18 kHz in the event of an output short or an overload which causes the regulated
output voltage to drop approximately 40% from the nominal output voltage. This self protection feature lowers the average dissipation of
the IC by lowering the minimum duty cycle from 5% down to approximately 2%.
4. Output (Pin 2) sourcing current. No diode, inductor or capacitor connected to output pin.
5. Feedback (Pin 4) removed from output and connected to 0 V.
6. Feedback (Pin 4) removed from output and connected to +12 V for the Adjustable, 3.3 V, and 5.0 V versions, and +25 V for the 12 V
and 15 V versions, to force the output transistor "off".
7. V
in
= 40 V.
4
IL2576
Fixed Output Voltage Versions
Cin 100 mF, 75 V, Aluminium Electrolytic
Cout 1000 mF, 25 V, Aluminium Electrolytic
D1 Schottky, MBR360
L1 100 mH, Pulse Eng. PE92108
R1 2.0 k, 0.1%
R2 6.12 k, 0.1%
Adjustable Output Voltage Versions
+
=
1
2
0
.
1
R
R
V
V
ref
out
,
-
=
0
.
1
1
2
ref
out
V
V
R
R
Where Vref = 1.23 V, R1 between 1.0 k and 5.0 k
5
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