SECOS S5U2596M

S5U2596M
150 KHz, 3A PWM
Elektronische Bauelemente
Step-Down DC/DC Converter
Description
The S5U2596M series of regulators are monolithic integrated circuit
that provides all active functions for a step-down (buck) switching
regulator, capable of driving 3A load with excellent line and load
regulation. These devices are available in fixed output voltages of
3.3V,5V,12V and an adjustable output version. The S5U2596M
series ioerate at a switching frequency of 150 KHz; thus allowing
smaller sized filter components than what would be needed with
lower frequency switching regulators. Available in standard 5-lead
TO-263 package with several different lead bend options. Other
feature include a guaranteed ± 4% to tolerance on output voltage
under specified input voltages and output load conditions. The 150
KHz ±15% is on the oscillator frequency. External shutdown is
included, featuring 80uA(Typ.) standby current. The output switch
includes cycle-by cycle current limiting, as well as thermal shutdown
for full protection under fault conditions.
Features
* Uses Readily Available Standard Inductors
* Operating Voltage Can Be Up To 22V
* Thermal Shutdown And Current Limit Protection
* 3.3V,5V,12V and adjustable Output Versions
REF.
A
b
L4
c
L1
E
Millimeter
Min.
4.40
0.66
0.00
0.36
2.29
9.80
REF.
Max.
4.80
c2
0.91
L2
0.30 B D
0.5
e
2.79
L
10.4
Millimeter
Min.
Max.
1.25
1.45
1.27 REF.
8.6
9.0
1.70 REF.
14.6
15.8
0˚
8˚
* TTL Shutdown Capability
* Built-in TTL On/Off Control
* Guaranteed 3A Output Current
* 150 KHz Fixed Frequency Internal Oscillator
Applications
* Positive To Negative Converter
* High-Effciency Step-Down Regulator
* One-ch Switching Regulators Simple
Block Diagram
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01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 1 of 6
S5U2596M
150 KHz, 3A PWM
Elektronische Bauelemente
Pin Function
Pin Name
Step-Down DC/DC Converter
Pin#
GND
VIN
1
Output
2
Ground
Feedback(FB)
NC
ON/OFF(SD)
3
4
5
Function
Description
This is the positive input supply
for the IC switching regulator. A suitable input bypass capacitor
must be present at this pin to minimize voltage transients and to supply the switching current
must be present at this pin to minimize voltage transients and to supply the switching current
needed by regulator.
0.5V,
V SAT) and
approximately
- 0.5V,
Internal
voltage
at this ispinconnected
switches from
between
(+V
Typicallyswitch.
a largeThe
storage
capacitor
thiscoupling
pin IN
to -ground
to insure
that the
. To minimize
to sensitive
circuitry,
the input
PC
with a duty cycle of approximately VOUT/V IN . To minimize coupling to sensitive circuitry, the
1.3VPC
board copper area connected to this pin should be keep to a minimum.
Circuit ground
or open= output enable.
Senses the regulated output
voltage
to
complete
the
feedback
loop
.
tage does not sag below the minimum dropout voltage during the load
Allows the switching regulator circuit to be shutdownV using
logic level
signals.
Thus
the
totalto
in order
fordrop
the
device
Allows the switching regulator circuit to be shutdownhigher
using than
logic Vout
level signals.
Thus
drop
the of
total
threshold
voltage
input supply current to approximately 150 A. Pulling this pin below a threshold voltage of
of
approximately 1.3V turns the regulator on, and pulling this pin above 1.3V (up to a maximum
18V) shuts the regulator down. If this shutdown feature is not needed, ON/OFF pin can be wired to of
18V) shuts the regulator down. If this shutdown feature is not needed, ON/OFF pin can be wired to
the ground pin.
Absolute Maximum Ratings
Parameter
Symbol
VCC
VSD
VFB
VOUT
PD
TST
TOP
VOP
Supply Voltage
ON/OFF Pin Input Voltage
Feedback Pin Voltage
Output Voltage to ground
Power Dissipation
Storage Temperature
Operating temperature
Operating Voltage
Ratings
24
-0.3 ~ +18
-0.3 ~ +18
-1
Internally Limited
-65 ~ +150
-40 ~ +125
+4.5 ~ +22
Unit
V
V
V
V
W
V
S5U2596M Electrical Characteristics
Specifications in boldface type are for full operating temperature range. The other type are for TJ=25
Parameter
Output Feedback
Symbol
VFB
Efficiency
Conditions
5 VIN 22V, 0.2A ILOAD 3A
VOUT=3V
VIN=12V, ILOAD=3A, VOUT=3V
.
Min
Typ
Max
Unit
1.193/1.180
1.230
1.267/1.280
V
74
%
S5U2596M-33 Electrical Characteristics
Specifications in boldface type are for full operating temperature range. The other type are for TJ=25
Parameter
Output Feedback
Symbol
VFB
Efficiency
Conditions
5.5V VIN 22V
0.2A ILOAD 3A
VIN=12V, ILOAD=3A
.
Min
Typ
Max
Unit
3.168/3.135
3.3
3.432/3.465
V
75
%
S5U2596M-50 Electrical Characteristics
Specifications in boldface type are for full operating temperature range. The other type are for TJ=25
Parameter
Output Feedback
Symbol
VFB
Efficiency
Conditions
8V VIN 22V
0.2A ILOAD 3A
VIN=12V, ILOAD=3A
.
Min
Typ
Max
Unit
4.80/4.75
5.0
5.20/5.25
V
80
%
S5U2596M-12 Electrical Characteristics
Specifications in boldface type are for full operating temperature range. The other type are for TJ=25
Parameter
Output Feedback
Efficiency
http://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Symbol
VFB
Conditions
15V VIN 22V
0.2A ILOAD 3A
VIN=16V, ILOAD=3A
.
Min
Typ
Max
Unit
11.52/11.40
12
12.48/12.60
V
89
%
Any changing of specification will not be informed individual
Page 2 of 6
S5U2596M
150 KHz, 3A PWM
Elektronische Bauelemente
Step-Down DC/DC Converter
All Output Voltage Version Electrical Characteristics
Specifications in boldface type are for full operating temperature range. The other type are for TJ=25
Parameter
Feedback bias current
Oscillator frequency
Symbol
IFB
Conditions
VFB=1.3V (adjustable version only)
FOSC
.
Min
127/110
Typ
-10
150
Max
-50/-100
173/173
Unit
nA
kHz
Oscillator frequency of
short circuit protect
FSCP
When current limit occurred and
VFB<0.5V, TA=25 .
5
15
25
kHz
Saturation voltage
VSAT
ILOAD=3A No outside circuit
VFB=0V force drive on
-
1.4
1.6/1.7
V
-
100
0
-
%
3.6
4.5
5.5/6.5
A
-
-
-200
uA
-
10
mA
mA
2.0
-5
5
-
Max. duty cycle (ON)
Max. duty cycle (OFF)
DC
Quiescent current
IQ
VFB=0V force drive on
VFB=12V force drive off
Peak current No outside circuit
VFB=0V force drive on
Output=0V, No outside circuit
VFB=12V force drive off
Output=-1V, VIN=22V
VFB=12V force drive off
Current limit
ICL
Output leakage current
IL
ON/OFF pin logic input
VIL
Low (Regulator ON)
Threshold Voltage
ON/OFF pin Logic input
current
VIH
High (Regulator OFF)
IH
VLOGIC=2.5V ( Regulator OFF)
-
IL
VLOGIC=0.5V ( Regulator ON)
-
-0.1
-1
-
150
200
-
3.5
-
-
23
-
ON/OFF pin input
current
Standby quiescent
current
-
JC
JA
-
V
-0.01
uA
ISTBY ON/OFF pin=5V, VIN=12V
Thermal Resistance
0.6
Junction to Case
Junction to Ambient with copper
area of approximately 3 in2
uA
/W
Unless otherwise specified, VIN=12V for 3.3V, 5V, adjustable version and VIN=18V for the 12V version. ILOAD=0.5A
Function Description
The TO-263 surface mount package tab was designed to be soldering to the copper on printed circuit board. The copper and the board are
the heat sink for this package and the other heat producing components, such as the catch diode and inductor. The PC board copper area
2
that the package is soldered to should be at least 0.8in , and ideally should have 2 or more square inches of 2 oz. Additional copper area
2
improves the thermal characteristics, but with copper area greater than approximately 6in , only small improvements in heat dissipation are
realized. If further thermal improvements are needed, double sided, multi-layer PC board with large copper areas and/or airflow will be
recommended.
The S5U2596M junction temperature rises above ambient temperature with a 2A 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 current higher than 3A
are used, double sided or multi-layer PC boards with lager 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. (One 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.
Package thermal resistance and junction temperature rise numbers are all approximate, and there are many factors will affect these
numbers. Some of these factors include board size, shape, thickness, position, location and even board temperature. Other factors are,
trace width, total printed circuit copper area, copper thickness, single or double-sided, multi-layer board and the amount of solder on the
board. The effectiveness of the PC board to dissipate heat also depends on the size, quantity and spacing of other components on the
board, as well as the surrounding air is still or moving. Furthermore, some of these components such as the catch diode will add heat to
the PC board and the heat can vary as the input voltage changes. For the inductor, depending on the physical size, type of core material
and the DC resistance, it could either act as a heat sink taking heat away from the board, or it could add heat to the board.
h tp://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 3 of 6
S5U2596M
150 KHz, 3A PWM
Elektronische Bauelemente
Step-Down DC/DC Converter
Typical Application Circuit
(1)Fixed Type Circuit
S596M
S5E2596M
S5E2596M
S5U2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
S5E2596M
-33
-33
-33
-33
-33
-33
BMKFE
-33
-33
-33
-33
-33
BMKFE
-33
BMKFE
-33
BMKFE
BMKFE
-33
-33
-33
-33
(2)Adjustable Type Circuit
BMKFE
S5U2596M
BMKFE
S5E2596M
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
-33
(3)Delay Start Circuit
BMKFE
S5U2596M
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
BMKFE
5
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01-Jun-2002 Rev. A
3
Any changing of specification will not be informed individual
Page 4 of 6
S5U2596M
Elektronische Bauelemente
150 KHz, 3A PWM
Step-Down DC/DC Converter
Typical Performance Characteristics
http://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
Page 5 of 6
S5U2596M
150 KHz, 3A PWM
Elektronische Bauelemente
GND
Step-Down DC/DC Converter
Description
Typically a large storage capacitor is connected from this pin to ground to insure that the input
1.3V
or open= output enable.
NC
http://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
tage does not sag below the minimum dropout voltage during the load
V higher than Vout in order for the device to
Any changing of specification will not be informed individual
Page 6 of 6