FOSLINK FSP3123K12E 150khz 3a pwm buck dc/dc converter Datasheet

150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
FEATURES
„
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Output voltage: 3.3V, 5.0V, 12V, and adjustable
output version
Adjustable version output voltage range:1.23V to
18V±4%
150KHz±15% fixed switching frequency
Voltage mode non-synchronous PWM control
Thermal-shutdown and current-limit protection
ON/OFF shutdown control input
Operating voltage can be up to 22V
Output load current: 3A
Low power standby mode
Built-in switching transistor on chip
TO220-5L,TO263-5L and PDIP8L packages
„
APPLICATIONS
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Simple High-efficiency step-down regulator
On-card switching regulators
Positive to negative converter
The FSP3123 series are monolithic IC that design for
a step-down DC/DC converter, and own the ability of
driving a 3A load without additional transistor
component. Due to reducing the number of external
component, the board space can be saved easily.
The external shutdown function can be controlled by
logic level and then come into standby mode. The
internal compensation makes feedback control have
good line and load regulation without external design.
Regarding protected function, thermal shutdown is to
prevent over temperature operating from damage,
and current limit is against over current operating of
the output switch. If current limit function occurred and
VFB is down to 0.5V below, the switching frequency
will be reduced. The FSP3123 series operates at a
switching frequency of 150 KHz thus allowing smaller
sized filter components than what would be needed
with lower frequency switching regulators. Other
features include a guaranteed ±4% tolerance on
output voltage under specified input voltage and
output load conditions, and ±15% on the oscillator
frequency. The output version included fixed 3.3V,
5V, 12V, and an adjustable type. The packages are
available in a standard 5-lead TO-220 package, a
5-lead TO-263 package or 8-lead PDIP.
„
PIN CONFIGURATION
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(1) TO220-5L
GENERAL DESCRIPTION
(2) TO263-5L
(Top View)
(Top View)
5
SD
4 FB
4
FB
3 GND
3
GND
2
OUTPUT
1
VIN
5 SD
2 OUTPUT
1 VIN
Metal Tab Gnd
Metal Tab Gnd
(3) PDIP8L
(Top View)
GND GND
8
1
7
2
GND
GND
6
5
3
VIN OUTPUT FB
1/11
4
SD
Symbol
TO220/TO263
PDIP
1
1
2
2
3
5~8
4
3
5
4
Name
Descriptions
Vin
Output
Gnd
FB
SD
Operating Voltage Input
Switching Output
Ground
Output Voltage Feedback Control
ON/OFF Shutdown
2007-6-12
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
VSD
VFB
VOUT
PD
TST
TOP
VOP
„
Paramrter
Supply Voltage
ON/OFF Pin input Voltage
Feedback Pin Voltage
Output Voltage to Ground
Power Dissipation
Storage Temperature
Operating Temperature
Operating Voltage
Rating
+24
-0.3 to +18
-0.3 to +18
-1
Internally Limited
-65 to +150
-40 to +125
+4.5 to +22
Unit
V
V
V
V
W
℃
℃
V
ELECTRICAL CHARACTERISTICS (ALL OUTPUT VOLTAGE VERSIONS)
Unless otherwise specified, VIN=12V for 3.3V,5V, adjustable version and VIN=18V for the 12V version. ILOAD=0.5A
Symbol
IB
FOSC
FCSP
Paramrter
Feedback bias current
Oscillator frequency
Short Circuit Oscillator
Frequency
VSAT
Saturation voltage
DC
Max.Duty Cycle(ON)
Min.Duty Cycle(OFF)
ICL
IL
IQ
ISTBY
VIL
VIH
IH
IL
θJC
θJA
Conditions
VFB=1.3V(Adjustable
version only)
Current limit
Output
leakage
current
Output=-1
Quiescent Current
Standby Quiesient
Current
Output=0
ON/OFF pin logic input
threshold voltage
ON/OFF pin logic input
current
ON/OFF pin input
current
Thermal Resistence
Thermal Resistence
with Copper Area of
Approximately 3 in2
When Current Limit
Occur and
VFB < 0.5V, TA=25°C
IOUT=3A
no outside circuit
VFB=0V force driver on
VFB=0V force driver on
VFB=12V force driver off
Peak current
no outside circuit
VFB=0V force driver on
no outside circuit
VFB=12V force driver off
VIN=22V
VFB=12V force driver off
ON/OFF Pin=5V
VIN=22V
Min.
-10
127
110
150
10
30
TO220-5L
Junction
to ambient
50
kHz
0
3.6
6.9
3.4
7.5
5
70
1.3
KHz
V
%
A
-50
µA
-30
10
200
250
mA
mA
0.6
µA
V
-15
µA
-5
2.5
3.5
12
℃/W
28
TO263-5L
23
PDIP8L
35
Specifications with boldface type are for full operating temperature range, the other type are for TJ=25ºC.
2/11
nA
2.0
VLOGIC=0.5V(ON)
Junction
to case
Unit
1.5
100
VLOGIC=2.5V(OFF)
TO220-5L
TO263-5L
PDIP8L
Max.
-50
-100
173
173
1.4
Low(regultaor ON)
High(regultaor OFF)
Typ.
2007-6-12
℃/W
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
ELECTRICAL CHARACTERISTICS (CONTINUED)
FSP3123-ADJ
FSP3123-3.3V
FSP3123-5.0V
FSP3123-12V
Symbol
Parameter
VFB
Output Feedback
η
Efficiency
VOUT
Output voltage
η
Efficiency
VOUT
Output voltage
η
Efficiency
VOUT
Output voltage
Conditions
5V≤VIN≤22V
0.2A≤ILOAD≤3A
VOUT programmed for
3V
VIN =12V, ILOAD =3A
5.5V≤VIN≤22V
0.2A≤ILOAD≤3A
VIN =12V,
ILOAD =3A
8V≤VIN≤22V
0.2A≤ILOAD≤3A
VIN =12V,
ILOAD =3A
15V≤VIN≤22V
0.2A≤ILOAD≤3A
Typ.
Limit
Unit
1.23
1.193/1.18
1.267/1.28
V
VMIN
VMAX
75
3.3
3.168/3.135
3.432/3.465
75
5
4.8/4.75
5.2/5.25
80
12
11.52/11.4
12.48/12.6
η
Efficiency
VIN =15V, ILOAD =3A
90
Specifications with boldface type are for full operating temperature range, the other type are for TJ=25ºC.
„
3/11
BLOCK DIAGRAM
2007-6-12
%
V
VMIN
VMAX
%
V
VMIN
VMAX
%
V
VMIN
VMAX
%
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
FUNCTION DESCRIPTION
Pin Function
VIN
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 currents needed by the regulator.
Ground
Circuit ground.
Output
Internal switch. The voltage at this pin switches between (VIN – VSAT ) and approximately – 0.5V, with a duty cycle
of approximately VOUT / VIN. To minimize coupling to sensitive circuitry, the PC board copper area connected to
this pin should be kept a minimum.
Feedback
Senses the regulated output voltage to complete the feedback loop.
ON/OFF
Allows the switching regulator circuit to be shutdown using logic level signals thus dropping the total input supply
current to approximately 150uA. 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 18V) shuts the regulator down. If this shutdown
feature is not needed, the ON/OFF pin can be wired to the ground pin.
Thermal Considerations
The FSP3123 is available in three packages, a 5-pin TO-220, 5-pin TO263 and a 8-pin PDIP Package. The
TO-220 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 FSP3123 junction temperature rises above
ambient temperature for a 3A load and different input and output voltages. The data for these curves was taken
with the FSP3123 (TO-220 package) operating as a buck switching regulator in an ambient temperature of 25 oC
(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 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 as the
catch diode and inductor. The PC board copper area that the package is soldered to should be at least 0.4 in 2,
and ideally should have 2 or more square inches of 2 oz. Additional copper area improves the thermal
characteristics, but with copper areas greater than approximately 6 in2, 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 FSP3123 (TO-263 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 2A 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.
Package thermal resistance and junction temperature rise numbers are all approximate, and there are many
factors that 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, multilayer 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 whether 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.
4/11
2007-6-12
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
TYPICAL APPLICATION CIRCUITS
(1) Fixed Output Circuit
(2) Adjustable Output Circuit
5/11
2007-6-12
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
6/11
TYPICAL PERFORMANCE CHARACTERISTICS
2007-6-12
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
7/11
TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED)
2007-6-12
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
„
ORDERING INFORMATION
FSP3123XXXX
Package:
T: TO220-5L
K: TO263-5L
N: PDIP8L
„
Temperature Grade:
Output Voltage: Packing:
Blank: Tube or Bulk E: -40~125℃
Blank: ADJ
A: Tape & Reel
33: 3.3V
50: 5.0V
12: 12V
MARKING INFORMATION
1) TO220-5L
2) TO263-5L
Logo
3123-VV
YYWWXX
Part Number:
3123-ADJ: ADJ
3123-33: 3.3V
3123-50: 5.0V
3123-12: 12V
Logo
3123-VV
YYWWXX
Part Number:
3123-ADJ: ADJ
3123-33: 3.3V
3123-50: 5.0V
3123-12: 12V
Internal Code
Internal Code
Date Code:
YY: Year (01=2001)
WW: Nth week (01~52)
Date Code:
YY: Year (01=2001)
WW: Nth week (01~52)
(3) PDIP8L
Logo
3123-VV
YYWWXX
Part number:
3123-ADJ: ADJ
3123-33: 3.3V
3123-50: 5.0V
3123-12: 12V
Internal code
Date code:
YY: Year (01=2001)
WW: Nth week (01~52)
8/11
2007-6-12
150KHZ 3A PWM BUCK DC/DC CONVERTER
„
FSP3123
PACKAGE INFORMATION
1) TO220-5L
E
A
P
L
D
H1
Q
F
e
C
b
J1
e1
Symbol
A
b
C
D
E
e
e1
F
H1
J1
L
P
Q
9/11
Min.
4.07
0.76
0.36
14.22
9.78
1.57
6.68
1.14
5.46
2.29
13.21
3.68
2.54
Dimensions In Millimeters
Nom.
Max.
4.45
4.82
0.89
1.02
0.50
0.64
14.86
15.50
10.16
10.54
1.71
1.85
6.81
6.93
1.27
1.40
6.16
6.86
2.74
3.18
13.97
14.73
3.81
3.94
2.73
2.92
Min.
0.160
0.030
0.014
0.560
0.385
0.062
0.263
0.045
0.215
0.090
0.520
0.145
0.100
Dimensions In Inches
Nom.
0.175
0.035
0.020
0.585
0.400
0.067
0.268
0.050
0.243
0.108
0.550
0.150
0.107
2007-6-12
Max.
0.190
0.040
0.025
0.610
0.415
0.073
0.273
0.055
0.270
0.125
0.580
0.155
0.115
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
2) TO263-5L
E
10.90
9.10
L2
D
15.70
L
2.50
e
1.00
B
1.70
Land Pattern Recommendation (Unit: mm)
A
C2
C
L1
Symbol
A
B
C
C2
D
E
e
L
L1
L2
10/11
Min.
4.07
0.51
0.36
1.14
8.20
9.65
1.57
14.45
1.78
Dimensions In Millimeters
Nom.
Max.
4.46
4.85
0.84
1.02
0.50
0.74
1.27
1.65
9.15
9.65
10.16
10.67
1.71
1.85
15.24
15.88
2.54
2.79
2.92
Min.
0.163
0.020
0.014
0.046
0.328
0.386
0.063
0.578
0.071
Dimensions In Inches
Nom.
0.176
0.033
0.020
0.050
0.360
0.400
0.068
0.600
0.100
2007-6-12
Max.
0.194
0.041
0.030
0.066
0.380
0.427
0.074
0.635
0.110
0.115
150KHZ 3A PWM BUCK DC/DC CONVERTER
FSP3123
(3) PDIP8L
D
E1
E-PIN 0.018inch
E
PIN #1INDENT 0.025 DEEP 0.006-0.008 Inch
15°(4х)
7°(4х)
C
A
A2
eB
S
e
A1
L
B
B2
B1
Symbol
A
A1
A2
B
B1
B2
C
D
E
E1
e
L
eB
S
11/11
Min.
0.38
3.1
0.36
1.4
0.81
0.20
9.02
7.62
6.15
2.92
8.38
0.71
Dimensions In Millimeters
Nom.
Max.
5.33
3.30
0.46
1.52
0.99
0.25
9.27
7.94
6.35
2.54
3.3
8.89
0.84
Min.
Dimensions In Inches
Nom.
3.5
0.56
1.65
1.14
0.36
9.53
8.26
6.55
0.015
0.122
0.014
0.055
0.032
0.008
0.335
0.300
0.242
3.81
9.40
0.97
0.115
0.330
0.028
0.130
0.018
0.060
0.039
0.010
0.365
0.313
0.250
0.100
0.130
0.350
0.033
2007-6-12
Max.
0.210
0.138
0.022
0.065
0.045
0.014
0.375
0.325
0.258
0.150
0.370
0.038
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