DMS ELECTRONIC COMPONENTS
EDS-parameters
DMS2576 Series
3A Step-Down Voltage Regulator
General Description
The DMS2576 series of regulators are mono-
lithic integrated circuits that provide all the active
functions for a step-down (buck) switching regula-
tor, capable of driving 3A load with excellent line
and load regulation. These devices are available in
fixed output voltages of 3.3V, 5V, 12V, 15V, and an
adjustable output version.
Requiring a minimum number of external com-
ponents, these regulators are simple to use and in-
clude internal frequency compensation and a fixed-
frequency oscillator.
The DMS2576 series offers a high-efficiency re-
placement for popular three-terminal linear regula-
tors. It substantially reduces the size of the heat
sink, and in some cases no heat sink is required.
A standard series of inductors optimized for use
with the DMS2576 are available from several dif-
ferent manufacturers. This feature greatly simpli-
fies the design of switch-mode power supplies.
Other features include a guaranteed ±4% tol-
erance on output voltage within specified input
voltages and output load conditions, and g10% on
the oscillator frequency. External shutdown is in-
cluded, featuring 80
µA
(typical) standby current.
The output switch includes cycle-by-cycle current
limiting, as well as thermal shutdown for full pro-
tection under fault conditions.
Features
– 3.3V, 5V, 12V, 15V, and adjustable output
versions
– Adjustable version output voltage range,
1.23V to 37V ±4% max over line and load con-
ditions
– Guaranteed 3A output current
– Wide input voltage range, 40V
– 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
– P+ Product Enhancement tested
Applications
– Simple high-efficiency step-down (buck) regu-
lator
– Efficient pre-regulator for linear regulators
– On-card switching regulators
– Positive to negative converter (Buck-Boost)
Typical Application (Fixed Output Voltage Versions)
DMS2576
-5.0
DMS ELECTRONIC COMPONENTS
Block Diagram
EDS-parameters
Absolute Maximum Ratings (Note 1)
Maximum Supply Voltage
ON/OFF Pin Input Voltage
Output Voltage to Ground
(Steady State)
Power Dissipation
Storage Temperature Range
Minimum ESD Rating
(C = 100 pF, R = 1.5 kΩ)
Lead Temperature
(Soldering, 10 Seconds)
Maximum Junction Temperature
45V
–0.3V
≤
V
≤
+V
IN
–1V
Internally Limited
–65
0
C to +150
0
C
2.5 kV
260
0
C
150
0
C
–40
0
C
≤
T
J
≤
+125
0
C
40V
Operating Ratings
Temperature Range
Supply Voltage
DMS ELECTRONIC COMPONENTS
EDS-parameters
DMS2576-3.3
Electrical Characteristics
Specifications with standard type face are for T
J
= 25
0
C, and those
with
boldface
type apply over full Operating Temperature Range.
Symbol
Parameter
Conditions
DMS2576-3.3
Typ
Limit (Note 2)
3.3
VOUT
VOUT
η
Output Voltage
Output Voltage
Efficiency
V
IN
= 12V, I
LOAD
= 0.5A
6V
≤
V
IN
≤
40V,
0.5A
≤
I
LOAD
≤
3A
V
IN
= 12V, I
LOAD
= 3A
Units
(Limits)
V
V(Min)
V(Max)
V
V(Min)
V(Max)
%
SYSTEM PARAMETERS (Note 3)
3.234
3.366
3.3
3.168/3.135
3.432/3.465
75
DMS2576-5.0
Electrical Characteristics
Specifications with standard type face are for T
J
= 25
0
C, and those
with
boldface
type apply over full Operating Temperature Range.
Symbol
Parameter
Conditions
DMS2576-5.0
Typ
Limit (Note 2)
5.0
VOUT
VOUT
η
Output Voltage
Output Voltage
Efficiency
V
IN
= 12V, I
LOAD
= 0.5A
8V
≤
V
IN
≤
40V,
0.5A
≤
I
LOAD
≤
3A
V
IN
= 12V, I
LOAD
= 3A
Units
(Limits)
V
V(Min)
V(Max)
V
V(Min)
V(Max)
%
SYSTEM PARAMETERS (Note 3)
4.900
5.100
5.0
4.800/4.750
5.200/5.250
77
DMS2576-12
Electrical Characteristics
Specifications with standard type face are for T
J
= 25
0
C, and those
with
boldface
type apply over full Operating Temperature Range.
Symbol
Parameter
Conditions
DMS2576-12
Typ
Limit (Note 2)
12
VOUT
VOUT
η
Output Voltage
Output Voltage
Efficiency
V
IN
= 25V, I
LOAD
= 0.5A
15V
≤
V
IN
≤
40V,
0.5A
≤
I
LOAD
≤
3A
V
IN
= 15V, I
LOAD
= 3A
Units
(Limits)
V
V(Min)
V(Max)
V
V(Min)
V(Max)
%
SYSTEM PARAMETERS (Note 3)
11.76
12.24
12
11.52/11.40
12.48/12.60
88
DMS ELECTRONIC COMPONENTS
EDS-parameters
DMS2576-15
Electrical Characteristics
Specifications with standard type face are for T
J
= 25
0
C, and those
with
boldface
type apply over full Operating Temperature Range.
Symbol
Parameter
Conditions
DMS2576-15
Typ
Limit (Note 2)
15
VOUT
VOUT
η
Output Voltage
Output Voltage
Efficiency
V
IN
= 25V, I
LOAD
= 0.5A
18V
≤
V
IN
≤
40V,
0.5A
≤
I
LOAD
≤
3A
V
IN
= 18V, I
LOAD
= 3A
Units
(Limits)
V
V(Min)
V(Max)
V
V(Min)
V(Max)
%
SYSTEM PARAMETERS (Note 3)
14.70
15.30
15
14.40/14.25
15.60/15.75
88
DMS2576-ADJ
Electrical Characteristics
Specifications with standard type face are for T
J
= 25
0
C, and those
with
boldface
type apply over full Operating Temperature Range.
Symbol
Parameter
Conditions
DMS2576-ADJ
Typ
Limit (Note 2)
1.230
1.217
1.243
1.230
1.193/1.18
1.267/1.28
77
Units
(Limits)
V
V(Min)
V(Max)
V
V(Min)
V(Max)
%
SYSTEM PARAMETERS (Note 3)
VOUT
VOUT
η
Output Voltage
Output Voltage
Efficiency
V
IN
= 12V, I
LOAD
= 0.5A
8V
≤
V
IN
≤
40V,
0.5A
≤
I
LOAD
≤
3A
V
IN
= 12V, I
LOAD
= 3A
DMS ELECTRONIC COMPONENTS
All Output Voltage Versions
EDS-parameters
Electrical Characteristics
Specifications with standard type face are for TJ=25°C, and those with
boldface type
apply over full Operating Temperature Range. Unless otherwise specified, V
IN
=
12V for the 3.3V, 5V, and Adjustable version, V
IN
= 25V for the 12V version, and V
IN
= 30V for the
15V version. I
LOAD
=500 mA.
Symbol
Parameter
Conditions
DMS2576-XX
Тур
Limit (Note 2)
50
52
47/42
58/63
Saturation Voltage
Max Duty Cycle (ON)
Current Limit
Output Leakage Current
Quiescent Current
I
OUT
=
ЗА
(Note 4)
(Note 5)
(Notes 4 and 11)
(Notes 6 and 7) Output = 0V
Output = –1V
Output = –1V
(Note 6)
ON/OFF Pin = 5V (OFF)
1.4
1.8/2.0
98
93
I
CL
I
L
I
Q
I
STBY
5.0
3.8/3.2
6.1/6.8
2
7.5
30
5
10
50
200
V
OUT
= 0V
V
OUT
= Nominal Output Volt-
age
ON/OFF Pin = 5V (OFF)
1.4
1.2
12
2.2/2.4
1.0/0.8
%
%(Min)
A
A(Min)
A(Max)
mA(Max)
mA
mA(Max)
mA
mA(Max)
µA
µA(Max)
V(Min)
V(Max)
100/500
Units
(Limits)
nA
kHz
kHz (Min)
kHz (Max)
V V(Max)
DEVICE PARAMETERS
Ib
Feedback Bias Current
f
O
V
SAT
DC
Oscillator Frequency
V
OUT
= 5V (Adjustable Version
Only)
(Note 11)
Standby Quiescent
Current
ON/OFF CONTROL
VIH
ON/OFF Pin
Logic Input Level
VIL
IIH
µA
ON/OFF Pin Input
30
µA(Max)
Current
µA
IIL
ON/OFF Pin = 0V (ON)
0
10
µA(Max)
Note 1:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings in-
dicate 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.
Note 2:
All limits guaranteed at room temperature (standard type face) and at
temperature extremes (bold type
face).
All room temperature limits are 100% production tested. All limits at
temperature extremes
are guaran-
teed via correlation using standard Statistical Quality Control (SQC) methods.
Note 3:
External components such as the catch diode, inductor, input and output capacitors can affect switching regu-
lator system performance. When the DMS2576 is used as shown in the
Figure 2
test circuit, system performance will
be as shown in system parameters section of Electrical Characteristics.
Note 4:
Output pin sourcing current. No diode, inductor or capacitor connected to output.
Note 5:
Feedback pin removed from output and connected to 0V.
Note 6:
Feedback pin removed from output and connected to a12V for the Adjustable, 3.3V, and 5V versions, and a
25V for the 12V and 15V versions, to force the output transistor OFF.
Note 7:
V
IN
= 40V.
Note 8:
Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically,
with % inch leads in a socket, or on a PC board with minimum copper area.
Note 9:
Junction to ambient thermal resistance (no external heat sink) for the 5 lead TO-220 package mounted vertically,
with % inch leads soldered to a PC board containing approximately 4 square inches of copper area surrounding the
leads.
Note 10:
If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area
thermally connected to the package. Using 0.5 square inches of copper area,
θ
JA
is 50°C/W, with 1 square inch of
copper area,
θ
JA
is 37°C/W, and with 1.6 or more square inches of copper area,
θ
JA
is 32°C/W.
Note 11:
The oscillator frequency reduces to approximately 11 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 power dissipation of the 1С by lowering the minimum duty cycle from 5% down to ap-
proximately 2%.
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