TS2576
3A / 52KHz Buck Switching Regulator
TO-220-5L
TO-263-5L
2
(D PAK)
Pin Definition:
1. Input
2. SW Output
3. Ground
4. Feedback
5. Enable
General Description
TS2576 Series are step-down switching regulators with all required active functions. It is capable of driving 3A load
with excellent line and load regulations. These devices are available in fixed output voltages of 3.3V, 5V and
adjustable output version.
TS2576 series operates at a switching frequency of 52kHz thus allowing smaller sized filter components than what
would be needed with lower frequency switching regulators. It substantially not only reduces the area of board size
but also the size of heat sink, and in some cases no heat sink is required. The ±4% tolerance on output voltage within
specified input voltages and output load conditions is guaranteed. Also, the oscillator frequency accuracy is within
±10%. External shutdown is included. Featuring 70µA (typical) standby current. The output switch includes cycle-by-
cycle current limiting, as well as thermal shutdown for full protection under fault conditions.
Features
●
●
●
●
●
●
●
●
●
●
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Output Voltage: 3.3V, 5V & Adjustable version
Adjustable Output Voltage Range 1.23V~37V ±4%
52kHz fixed switching frequency
Voltage Mode Non-synchronous PWM control
Thermal Shutdown and Current Limit Protection
ON/OFF Shutdown Control Input
High Efficiency
Short Circuit Protect (SCP)
Operating Voltage Can be up to 40V
Output Load Current 3A
Low Power Standby Mode
P+ Product Enhancement Tested
Ordering Information
Part No.
Package
Packing
TS2576CZ5xx C0
TO-220-5L
50pcs / Tube
TS2576CM5xx RN
TO-263-5L
800pcs / 13” Reel
Note: Where
xx
denotes voltage option, available are
50=
5.0V
33=
3.3V
Leave blank for adjustable version
Application
●
●
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Simple High-efficiency Step down Regulator
On-Card Switching Regulators
Positive to Negative Converter
Absolute Maximum Rating
Parameter
Maximum Supply Voltage
Recommend Operating Supply Voltage
SW, EN Pin Input Voltage
Feedback Pin Voltage
Power Dissipation
Output Voltage to Ground
Storage Temperature Range
Operating Temperature Range
ESD Susceptibility (HBM)
Symbol
V
CC
V
OP
V
SW
, V
EN
V
FB
P
D
V
OUT
T
ST
T
OP
Limit
+45
4.5 to 40
-0.3 to +25
-0.3 to +25
Internally Limited
-1
-65 to +150
-40 to +125
2
Unit
V
V
V
V
W
V
o
o
C
C
kV
1/8
Version: A07
TS2576
3A / 52KHz Buck Switching Regulator
Thermal Information
Parameter
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
TO-220-5L
TO-263-5L
TO-220-5L
TO-263-5L
Symbol
Ө
JC
Ө
JA
Maximum
2
2
65 (note 1)
50 (note 2)
Unit
o
C/W
C/W
o
Note1:
Ө
JA
is measured on the PCB with minimum copper area.
2
Note2:
Ө
JA
is measured with the PCB copper area (need connect to GROUND pins) of approximately 0.5 in
Electrical Specifications (All Output Voltage Version)
(Ta = 25 C unless otherwise noted, V
IN
=12V for 3.3V, 5V, Adjustable version. I
LOAD
=0.5A)
o
Parameter
Output Feedback
Efficiency
Output Feedback
Efficiency
Output Feedback
Efficiency
Feedback Bias Current
Oscillator Frequency
Soft-Start Time
Current Limit
Saturation Voltage
ON/OFF Pin Logic Input Threshold
Voltage
ON/OFF Pin Logic Input Current
Maximum Duty Cycle (ON)
Maximum Duty Cycle (OFF)
Quiescent Current
Standby Quiescent Current
SW Pin Leakage
Current
SW pin = 0
SW pin = -1
5V
3.3V
ADJ
Symbol
V
FB
η
V
FB
η
V
FB
η
I
FB
F
OSC
T
SS
I
CL
V
SAT
V
IL
V
IH
I
L
I
H
DC
I
Q
I
STBY
I
SWL
Test Condition
4.5V≤ V
IN
≤40V
0.2A≤ I
LOAD
≤3A
V
IN
=12V, I
LOAD
=3A
4.75V≤ V
IN
≤40V
0.2A≤ I
LOAD
≤3A
V
IN
=12V, I
LOAD
=3A
7V≤ V
IN
≤40V
0.2A≤ I
LOAD
≤3A
V
IN
=12V, I
LOAD
=3A
V
OUT
= 5V (Adjustable Version)
Rising edge of EN on to I
CL
Pear Current, no outside circuit
V
FB
=0V force driver on
I
OUT
=3A, No outside circuit
V
FB
=0V force driver on
Low (regulator ON)
High (regulator OFF)
V
LOGIC
=5V (OFF)
V
LOGIC
=0V (ON)
V
FB
=0V force driver on
V
FB
=12V force driver off
V
FB
=12V force driver off
ON/OFF pin=5V
V
IN
=40V
No outside circuit,
V
FB
=12V force driver off
V
IN
=12V
Min
1.180
--
3.135
--
4.75
--
--
47
--
5.9
--
--
2.2
--
--
93
--
--
--
--
--
--
Typ
1.23
75
3.3V
75
5
77
50
52
3
--
1.4
1.2
1.4
12
0
98
0
5
70
0.3
7.5
Max
1.280
--
3.465
--
5.25
--
100
58
--
--
1.8
1.0
--
30
10
--
--
10
200
250
2
30
Unit
V
%
V
%
V
%
nA
KHz
mS
A
V
V
µA
%
mA
µA
mA
mA
2/8
Version: A07
TS2576
3A / 52KHz Buck Switching Regulator
Block Diagram
3/8
Version: A07
TS2576
3A / 52KHz Buck Switching Regulator
Typical Application Circuit
1. Adjustable Output Voltage Version
2. Fixed Output Voltage Version
3. Adjustable Output Voltage Version with Delayed Startup
4/8
Version: A07
TS2576
3A / 52KHz Buck Switching Regulator
Pin Function Description
Vcc
This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be presented at
this pin to minimize voltage transients and to supply the switching currents needed by the regulator.
Ground
Circuit ground
SW Output
Internal switch. The voltage at this pin switches between (+Vcc – Vsat) and approximately – 0.5V, with a duty cycle of
approximately Vout / Vcc. To minimize coupling to sensitive circuitry, the PC board copper area connected to this pin
should be minimized.
Feedback
Sense the regulated output voltage to complete the feedback loop.
Enable
Allows the switching regulator circuit to be shutdown using logic level signals thus dropping the total input supply
current to approximately 100uA. 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 Vcc) shuts the regulator down. If this shutdown feature is not
needed, the EN pin can be wired to the ground pin.
Thermal Considerations
The TS2576 is available in two packages, a TO-220-5L and TO-263-5L.
The TO-220-5L package needs a heat sink under most conditions. The size of the heat sink depends on the input
voltage, the output voltage, the load current and the ambient temperature. The TS2576 junction temperature rises
above ambient temperature for a 3A load and different input and output voltages. The data for these curves was taken
o
with the TS2576CZ5 (TO-220-5L package) operating as a buck switching regulator in an ambient temperature of 25 C
(still air). These temperature rise numbers are all approximate and there are many factors that can affect these
temperatures. Higher ambient temperatures require more heat sinking.
The TO-263-5L surface mount package tab is designed to be soldered to the copper on a printed circuit board. The
copper and the board are the heat sink for this package and the other heat producing components, such
2
as the catch
diode and inductor. The PC board copper area that the package is soldered to should be at least 0.8 in , and ideally
should have 2 or more square inches of 2oz.
2
Additional copper area improves the thermal characteristics, but with
copper areas greater than approximately 6 in , only small improvements in heat dissipation are realized. If further
thermal improvements are needed, double sided, multilayer PC board with large copper areas and/or airflow are
recommended.
The TS2576 (TO-263-5L package) junction temperature rise above ambient temperature with a 3A load for various
input and output voltages. This data was taken with the circuit operating as a buck switching regulator with all
components mounted on a PC board to simulate the junction temperature under actual operating conditions. This
curve can be used for a quick check for the approximate junction temperature for various conditions, but be aware that
there are many factors that can affect the junction temperature. When load currents higher than 3A are used, double
sided or multilayer PC boards with large copper areas and/or airflow might be needed, especially for high ambient
temperatures and high output voltages.
For the best thermal performance, wide copper traces and generous amounts of printed circuit board copper should be
used in the board layout. (Once exception to this is the output (switch) pin, which should not have large areas of
copper.) Large areas of copper provide the best transfer of heat (lower thermal resistance) to the surrounding air, and
moving air lowers the thermal resistance even further.
5/8
Version: A07
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