L5972D Datasheet by STMicroelectronics

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The output voltage can be set fro The device uses an internal PVC transistor (with a typical Rdson 0 switching element to minimize th external components. An internal oscillatorfixes the sw a1 250kHZ. Hawng a minimum input voltage particularly suitable for 5V bus, a computer related applications. Pulse by pulse current limit with frequency modulation olfers an e current short circuit protection. car radio, DC modules I Computer: or cards, optical storag I Industrial: cha DCrDC converters Figure 1. Tes t VlN = 4.4 CI 10uF 35v CERAMIC DDS/Midst} October 2007 Rev 10
October 2007 Rev 10 1/15
15
L5972D
2A switch step down switching regulator
Features
2A internal switch
Operating input voltage from 4.4V to 36V
Output voltage adjustable from 1.235V to 35V
Low dropout operation: 100% duty cycle
250kHz Internally fixed frequency
Voltage feedforward
Zero load current operation
Internal current limiting
Protection against feedback disconnection
Thermal shutdown
Applications
Consumer: STB, DVD, TV, VCR, car radio,
LCD monitors
Networking: XDSL, modems, DC-DC modules
Computer: printers, audio/graphic cards,
optical storage, hard disk drive
Industrial: changers, car battery, DC-DC
converters
Figure 1. Test application circuit
Description
The L5972D is a step down monolithic power
switching regulator with a minimum switch current
limit of 2A so it is able to deliver more than 1.5A
DC current to the load depending on the
application conditions.
The output voltage can be set from 1.235V to 35V.
The device uses an internal P-Channel D-MOS
transistor (with a typical Rdson of 250m) as
switching element to minimize the size of the
external components.
An internal oscillator fixes the switching frequency
at 250kHz.
Having a minimum input voltage of 4.4V only, it is
particularly suitable for 5V bus, available in all
computer related applications.
Pulse by pulse current limit with the internal
frequency modulation offers an effective constant
current short circuit protection.
SO8
www.st.com
D03IN1436
8
2
45
1
7
L5972D
C1
10µF
35V
CERAMIC
C2
100µF
10V
VOUT=3.3V
VIN = 4.4V to 35V
R1
5.6K
R2
3.3K
R3
4.7K
C4
22nF
C3
220pF
3
L1 33µH
6
D1
STPS2L40U
COMP
VCC OUT
FB
GND
Contents L5972D
2/15
Contents
1 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Application ideas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8 Order code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
_I__I__I__I_ CECE
L5972D Pin settings
3/15
1 Pin settings
1.1 Pin connection
Figure 2. Pin connection (top view)
1.2 Pin description
OUT
GND
GND
COMP
1
3
2
4
VCC
GND
GND
FB
8
7
6
5
D02IN1367
Table 1. Pin description
N° Pin Description
1 OUT Regulator output.
2,3,6,7 GND Ground.
4 COMP E/A output for frequency compensation.
5FB
Feedback input. Connecting directly to this pin results in an output
voltage of 1.23V. An external resistive divider is required for higher
output voltages.
8 VCC Unregulated DC input voltage.
Electrical data L5972D
4/15
2 Electrical data
2.1 Maximum ratings
2.2 Thermal data
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
V8Input voltage 40 V
V1
Out pin DC voltage
Out pin peak voltage at t = 0.1µs
-1 to 40
-5 to 40
V
V
I1Maximum output current int. limit.
V4, V5Analog pins 4 V
Ptot Power dissipation at TA 70°C 1.2 W
TjOperating junction temperature range -40 to 150 °C
Tstg Storage temperature range -55 to 150 °C
Table 3. Thermal data
Symbol Parameter SO8 Unit
RthJA Maximum thermal resistance junction-ambient 65 (1)
1. Package mounted on board
°C/W
CC
L5972D Electrical characteristics
5/15
3 Electrical characteristics
Table 4. Electrical characteristics
( T
J
= 25°C, V
CC
= 12V, unless otherwise specified)
Symbol Parameter Test condition Min Typ Max Unit
VCC
Operating input
voltage range Vo = 1.235V; Io = 2A (1)
1. Specification Referred to TJ from -40 to 125°C. Specification over the -40 to +125 TJ Temperature range
are assured by design, characterization and statistical correlation.
4.4 36 V
RDS(on)
Mosfet on
Resistance
(1) 0.250 0.5
Il
Maximum limiting
current VCC = 4.4V to 36V 2 2.5 3 A
fsSwitching frequency
(1) 212 250 280 kHz
225 250 275 kHz
Duty cycle 0 100 %
Dynamic characteristics (see test circuit ).
V5Voltage feedback 4.4V < VCC < 36V,
20mA < IO < 2A
1.220 1.235 1.25 V
(1) 1.198 1.235 1.272 V
h Efficiency VO = 5V, VCC = 12V 90 %
DC characteristics
Iqop
Total operating
quiescent current
(1) 35mA
IqQuiescent current Duty cycle = 0;
VFB = 1.5V 2.5 mA
Error amplfier
VOH
High level output
voltage VFB = 1V 3.5 V
VOL
Low level output
voltage VFB = 1.5V 0.4 V
Io source
Source output
current
VCOMP = 1.9V;
VFB = 1V 200 300 µA
Io sink Sink output current VCOMP = 1.9V;
VFB = 1.5V 11.5 mA
IbSource bias current 2.5 4 µA
DC open loop gain RL = 50 65 dB
gm Transconductance
Icomp = -0.1mA to
0.1mA
VCOMP = 1.9V
2.3 mS
Typical characteristics L5972D
6/15
4 Typical characteristics
Figure 3. Output voltage vs. junction
temperature
Figure 4. Quiescent current vs.
junction temperature
Figure 5. Line regulator Figure 6. Shutdown current vs.
junction temperature
Figure 7. Output voltage vs. junction
temperature
Figure 8. Switching frequency vs.
junction temperature
3.276
3.28
3.284
3.288
3.292
3.296
3.3
3.304
3.308
3.312
00.511.5
Io (A)
Vo (V)
Tj = 125°C
Tj = 25°C
Vcc = 12V
Vo = 3.3V
1.2
1.4
1.6
1.8
2
-50 050
100 150
Tj (°C)
Iq (mA)
Vcc = 12V
DC = 0%
3.276
3.28
3.284
3.288
3.292
3.296
3.3
3.304
3.308
3.312
010203040
Vcc (V)
Tj = 125°C
Tj = 25°C
Vcc = 12V
Vo = 3.3V
Vo (V)
30
40
50
60
70
-50 050 100 150
Ishd (µA)
Vcc = 12V
Tj (°C)
Tj (°C)
Vcc=12V
1.2
1.21
1.22
1.23
1.24
1.25
-50 0 50 100 150
Vo (V)
Vcc = 12V
1.2
1.4
1.6
1.8
2
-50 050
100 150
Tj (°C)
Iq (mA)
Vcc = 12V
DC = 0%
1on _ 25v - CERAMiC D03W1A38 -— Table 5. Component list Reference Part number Description Manu C1 GRM32DR61E106KA12L 10pF. 25V MURATA CZ POSCAP 10TPB100M 100pF, 10V Sanyo C3 C1206C221J5GAC 220pF, 5%, 50V KEMET CA C1206C223K5RAC 22nF, 10%, 50V KEMET R1 5.6K, 1%, 0.1W 0603 Neohm R2 3.3K, 1%, 0.1W 0603 Neohm R3 4.7K, 1%, 0.1W 0603 Neohm D1 STPSZLZSU 2A, 25V ST L1 D03316P-333 33pH, 2 1A COILCRA
L5972D Application circuit
7/15
5 Application circuit
In figure 8 is shown the demo board application circuit for the device in SMD version, where
the input supply voltage, Vcc, can range from 4.4V to 25V due to the rated voltage of the
input capacitor and the output voltage is adjustable from 1.235V to Vcc.
Figure 9. Demo board application circuit
Table 5. Component list
Reference Part number Description Manufacturer
C1 GRM32DR61E106KA12L 10µF, 25V MURATA
C2 POSCAP 10TPB100M 100µF, 10V Sanyo
C3 C1206C221J5GAC 220pF, 5%, 50V KEMET
C4 C1206C223K5RAC 22nF, 10%, 50V KEMET
R1 5.6K, 1%, 0.1W 0603 Neohm
R2 3.3K, 1%, 0.1W 0603 Neohm
R3 4.7K, 1%, 0.1W 0603 Neohm
D1 STPS2L25U 2A, 25V ST
L1 DO3316P-333 33µH, 2.1A COILCRAFT
D03IN1438
8
2
45
1
7
L5972D
C1
10µF
25V
CERAMIC
C2
100µF
10V
VOUT=3.3V
VIN = 4.4V to 25V
R1
5.6K
R2
3.3K
R3
4.7K
C4
22nF
C3
220pF
3
L1 33µH
6
D1
STPS2L25U
COMP
VCC OUT
FB
GND
A5972D EJAL m m yLI® 82 Du D Em LJ c1
Application circuit L5972D
8/15
Figure 10. PCB layout (component side)
Figure 11. PCB layout (bottom side)
Figure 12. PCB layout (front side)
Sideways two graphs show the TJ versus output current in different conditions of the input
and output voltage.
L5972D Figure 13. Junction temperature vs output current Figure 14. Ef mm mo 0 so a vm:5v Yamb :25 >5 me me 500 500 me zoo 200 D204D50E1121615182 in“! Human“ m Figure 15. Junction temperature vs output current Figure 16. Eflicie mm mm 900 WM“ va=5v va=s av 5“ “ Tamra: 251: 700 500 500 400 300 200 azuoasnsi iziéiélfiz mm Eflicbmy m m as as
L5972D Application circuit
9/15
Figure 13. Junction temperature vs
output current
Figure 14. Efficiency vs output current
Figure 15. Junction temperature vs
output current
Figure 16. Efficiency vs output current
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Io(A)
TJ(°C)
Vin=5V
Tamb.=25 °C
Vo=1.8V
Vo=2.5V Vo=3.3V
67
69
71
73
75
77
79
81
83
85
87
89
91
93
95
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7
Io (A)
Efficiency (%)
Vo=1.8V
Vo=2.5V
Vo=3.3V
Vin=5V
Vo=1.8V
Vo=2.5V
Vo=3.3V
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Io(A)
TJ(°C)
Vo=2.5V
Vo=3.3V
Vo=5V
Vin=12V
Tamb= 25°C
70
72
74
76
78
80
82
84
86
88
90
92
94
96
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7
Io (A)
Efficiency (%)
Vin=12V
Vo=2.5V
Vo=3.3V
Vo=5V
Vin=12V
Vo=2.5V
Vo=3.3V
Vo=5V
Wfi
Application ideas L5972D
10/15
6 Application ideas
Figure 17. Positive buck-boost regulator
Figure 18. Buck-boost regulator
Figure 19. Dual output voltage with auxiliary winding
VIN=5V
C1
10uF
10V
Ceramic
D1
STPS2L25U
Vcc
COMP
GND
OUT
FB
L5972D
1
3
7
5
6
4
8
2
R3
4.7k
L1
33uH
24k
2.7k
C3
22nF
C4
100uF
16V
VOUT=12V/0.45A
C2
220pF
D2
STPS2L25U
M1
STN4NE03L
VIN=5V
C1
10uF
10V
Ceramic
D1
STPS2L25U
Vcc
COMP
GND
OUT
FB
L5972D
1
3
7
5
6
4
8
2
R3
4.7k
L1
33uH
2.7k
24k
C4
22nF
C5
100uF
16V
VOUT=-12V/0.45A
C3
220pF
C2
10uF
25V
Ceramic
VIN=12V
C1
10uF
25V
D1
STPS2L25U
Vcc
COMP
GND
OUT
FB
L5972D
1
3
7
5
6
4
8
2
R3
4.7k
C3
22nF
C4
100uF
10V
VOUT=3.3V
C2
220pF
VOUT1=5V
50mA
D2
STPS2L25U
C5
47uF
10V
N1
N2
n=N1/N2=2
L5972D Package mechanical data
11/15
7 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect . The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com
M43 cm PLANE gig 7 0016023 C i7
Package mechanical data L5972D
12/15
Table 6. SO-8 Mechanical data
Dim.
mm. inch
Min Typ Max Min Typ Max
A 1.35 1.75 0.053 0.069
A1 0.10 0.25 0.004 0.010
A2 1.10 1.65 0.043 0.065
B 0.33 0.51 0.013 0.020
C 0.19 0.25 0.007 0.010
D (1)
1. Dimensions D does not include mold flash, protru-sions or gate burrs. Mold flash, potrusions or gate burrs
shall not exceed 0.15mm (.006inch) in total (both side).
4.80 5.00 0.189 0.197
E 3.80 4.00 0.15 0.157
e 1.27 0.050
H 5.80 6.20 0.228 0.244
h 0.25 0.50 0.010 0.020
L 0.40 1.27 0.016 0.050
k 0° (min.), 8° (max.)
ddd 0.10 0.004
Figure 20. Package dimensions
L5972D Order codes
13/15
8 Order codes
Table 7. Order codes
Part number Package Packaging
L5972D SO8 Tube
L5972D013TR SO8 Tape and reel
Revision history L5972D
14/15
9 Revision history
Table 8. Revision history
Date Revision Changes
02-Feb-2007 8 Updated Table 5 on page 7
10-Apr-2007 9 Mechanical data typo
16-Oct-2007 10 Updated Section 5: Application circuit on page 7
L5972D
15/15
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