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Электронный компонент: L5970

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L5970D
May 2003
s
UP TO 1A OUTPUT CURRENT
s
OPERATING INPUT VOLTAGE FROM 4.4V
TO 36V
s
3.3V / (2%) / REFERENCE VOLTAGE
s
OUTPUT VOLTAGE ADJUSTABLE FROM
1.2V TO 35V
s
LOW DROPOUT OPERATION: 100% DUTY
CYCLE
s
250KHz INTERNALLY FIXED FREQUENCY
s
VOLTAGE FEEDFORWARD
s
ZERO LOAD CURRENT OPERATION
s
INTERNAL CURRENT LIMITING
s
INHIBIT FOR ZERO CURRENT
CONSUMPTION
s
SINCHRONIZATION
s
PROTECTION AGAINST FEEDBACK
DISCONNECTION
s
THERMAL SHUTDOWN
APPLICATIONS:
s
CONSUMER: STB, DVD, TV, VCR,CAR
RADIO, LCD MONITORS
s
NETWORKING: XDSL, MODEMS,DC-DC
MODULES
s
COMPUTER: PRINTERS, AUDIO/GRAPHIC
CARDS, OPTICAL STORAGE, HARD DISK
DRIVE
s
INDUSTRIAL: CHARGERS, CAR BATTERY
DC-DC CONVERTERS
DESCRIPTION
The L5970D is a step down monolithic power
switching regulator capable to deliver up to 1A at
output voltages from 1.2V 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 ex-
ternal 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 fre-
quency modulation offers an effective constant
current short circuit protection.
SO8
ORDERING NUMBERS: L5970D (SO8)
L5970D013TR (T&R)
UP TO 1A STEP DOWN SWITCHING REGULATOR
TEST APPLICATION CIRCUIT
D98IN954C
8
2
4
5
1
7
L5970D
C1
10
F
35V
CERAMIC
C2
100
F
10V
VOUT=3.3V
VIN = 4.4V to 35V
R1
5.6K
R2
3.3K
R3
4.7K
C4
22nF
C3
220pF
3
6
D1
STPS2L40U
3.3V
INH.
SYNC.
COMP
VCC
VREF
OUT
FB
GND
L1 33
H
L5970D
2/10
PINS CONNECTION (Top View)
PINS FUNCTION
THERMAL DATA
(*) Package mounted on board
ABSOLUTE MAXIMUM RATINGS
N.
Name
Description
1
OUT
Regulator Output.
2
SYNC
Master/slave synchronization.
3
INH
A logical signal (active high) disables the device. If INH not used the pin must be grounded.
When it is open an internal pull-up disable the device.
4
COMP
E/A output for frequency compensation.
5
FB
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.
6
V
REF
3.3V V
REF
. No cap is requested for stability.
7
GND
Ground.
8
V
CC
Unregulated DC input voltage.
Symbol
Parameter
Value
Unit
R
th (j-amb)
Thermal Resistance Junction to ambient Max.
120 (*)
C/W
Symbol
Parameter
Value
Unit
V
8
Input Voltage
40
V
V
1
Output DC voltage
Output peak voltage at t = 0.1
s
-1 to 40
-5 to 40
V
V
I
1
Maximum output current
int. limit.
V
4
, V
5
Analog pins
4
V
V
3
INH
-0.3V to V
CC
V
2
SYNC
-0.3 to 4
V
P
tot
Power dissipation at T
amb
60C
0.75
W
T
j
Operating junction temperature range
-40 to 150
C
T
stg
Storage temperature range
-55 to 150
C
OUT
SYNC
INH
COMP
1
3
2
4
VCC
VREF
GND
FB
8
7
6
5
D98IN955
3/10
L5970D
ELECTRICAL CHARACTERISTCS (Tj = 25C, V
CC
= 12V, unless otherwise specified.)
(*) Specification Referred to T
j
from -40 to +125C (1).
Note (1): Specification over the -40 to +125 Tj Temperature range are assured by design, characterization and statistical correlation.
Note (2): Guaranteed by design.
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
V
CC
Operating input voltage
range
V
o
= 1.235V; I
o
= 1A
*
4.4
36
V
V
d
Dropout voltage
V
CC
= 4.4V; I
o
= 1A
*
0.25
0.5
V
I
l
Maximum limiting current
V
CC
= 4.4V to 36V
*
1.5
1.87
2.25
A
fs
Switching frequency
*
212
250
280
KHz
225
250
275
KHz
Duty cycle
0
100
%
DYNAMIC CHARACTERISTICS (see test circuit fig. xx note 1).
V
5
Voltage feedback
4.4V < V
CC
< 36V,
20mA < I
O
< 1A
1.220
1.235
1.25
V
*
1.198
1.235
1.272
V
Efficiency
V
O
= 5V, V
CC
= 12V
90
%
DC CHARACTERISTICS
I
qop
Total operating quiescent
current
*
3
5
mA
I
q
Quiescent current
Duty Cycle = 0; VFB = 1.5V
2.5
mA
I
qst-by
Total stand-by quiescent
current
V
inh
> 2.2V
V
CC
= 36V; V
inh
> 2.2V
*
*
50
80
100
150
A
A
INHIBIT
INH Threshold voltage
Device ON
0.8
V
Device OFF
2.2
V
ERROR AMPLIFIER
V
OH
High level output voltage
V
FB
= 1V
3.5
V
V
OL
Low level output voltage
V
FB
= 1.5V
0.4
V
I
o source
Source output current
V
COMP
= 1.9V; V
FB
= 1V
200
300
A
I
o sink
Sink output current
V
comp
= 1.9V; V
FB
= 1.5V
1
1.5
mA
I
b
Source bias current
2.5
4
A
DC open loop gain
R
L
=
50
65
dB
gm
Transconductance
I
comp
= -0.1mA to 0.1mA
V
comp
= 1.9V
2.3
mS
SYNC FUNCTION
High Input Voltage
V
CC
= 4.4V to 36V
2.5
V
REF
V
Low Input Voltage
V
CC
= 4.4V to 36V
0.74
V
Slave Sink Current
V
sync
= 0.74V
(2)
V
sync
= 2.33V
0.11
0.21
0.25
0.45
mA
mA
Master Output Amplitude
I
source
= 3mA
2.75
3
V
Output Pulse Width
no load, V
sync
= 1.65V
0.20
0.35
s
REFERENCE SECTION
Reference Voltage
3.234
3.3
3.366
V
I
REF
= 0 to 5mA
V
CC
= 4.4V to 36V
*
3.2
3.3
3.399
V
Line Regulation
I
REF
= 0mA
V
CC
= 4.4V to 36V
5
10
mV
Load Regulation
I
REF
= 0 to 5mA
8
15
mV
Short Circuit Current
10
8
30
mA
L5970D
4/10
Figure 1. Junction Temperature vs. Output
Current (SO8) *)
Figure 2. Junction Temperature vs. Output
Current (SO8) *)
Figure 3. Junction Temperature vs. Output
Current (SO8) *)
Figure 4. Load Regulation
Figure 5. Line Regulation
Figure 6. Output Voltage vs. Junction
Temperature
*) Package mounted on demoboard
20
30
40
50
60
70
80
90
100
110
120
130
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Io(A)
Tj(C)
Vo=3.3V
Vo=2.5V
Vo=1.8V
Vcc=5V
Tamb=25C
20
30
40
50
60
70
80
90
100
110
120
130
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Io(A)
Tj(C)
Vo=5V
Vo=2.5V
Vo=3.3V
Vcc=12V
Tamb=25C
0
20
40
60
80
100
120
140
0.2
0.4
0.6
0.8
1
1.2
1.4
Io(A)
Tj(C)
Vo=18V
Vo=12V
Vo=5V
Vcc=24V
Tamb=25C
3.276
3.28
3.284
3.288
3.292
3.296
3.3
3.304
3.308
3.312
0
0.5
1
1.5
Io (A)
Vo (V)
Tj = 125C
Tj = 25C
Vcc = 12V
Vo = 3.3V
3.276
3.28
3.284
3.288
3.292
3.296
3.3
3.304
3.308
3.312
0
10
20
30
40
Vcc (V)
Tj = 125C
Tj = 25C
Vcc = 12V
Vo = 3.3V
Vo (V)
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
5/10
L5970D
Figure 7. Quiescent Current vs. Junction
Temperature
Figure 8. Shutdown Current vs.Junction
Temperature
Figure 9. Switching Frequency vs.Junction
Temperature
1.2
1.4
1.6
1.8
2
-50
0
50
100
150
Tj (C)
Iq (mA)
Vcc = 12V
DC = 0%
30
40
50
60
70
-50
0
50
100
150
Ishd (
A)
Vcc = 12V
Tj (C)
220
230
240
250
260
-50
0
50
100
150
Tj (C)
Fsw (KHz)
Vcc = 12V
Vo = 3.3V
L5970D
6/10
Figure 10. Demoboard schematic
Part list demoboard
Reference
Part Number
Description
Manufacturer
C1
10
F, 25V
TOKIN
C2
POSCAP 10TPB100M
100
F, 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
STMicroelectronics
L1
DO3316P-333
33
H, 2A
COILCRAFT
D03IN1437
8
2
4
5
1
7
L5970D
C1
10
F
25V
CERAMIC
C2
100
F
10V
VOUT=3.3V
VIN = 4.4V to 25V
R1
5.6K
R2
3.3K
R3
4.7K
C4
22nF
C3
220pF
3
6
D1
STPS2L25U
3.3V
INH.
SYNC.
COMP
VCC
VREF
OUT
FB
GND
L1 33
H
Figure 11. Efficiency vs. Output Current
Figure 12. Efficiency vs. Output Current
70
72
74
76
78
80
82
84
86
88
90
92
94
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Io (A)
Effic
i
e
n
c
y
(%
)
Vo=3.3V
Vo=2.5V
Vo=1.8V
Vcc=5V
70
72
74
76
78
80
82
84
86
88
90
92
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Io (A)
Effic
i
e
n
c
y
(%
)
Vcc=12V
Vo=5V
Vo=3.3V
Vo=2.5V
7/10
L5970D
Figure 13. PCB layout (component side)
Figure 14. PCB layout (bottom side)
Figure 15. PCB layout (front side)
42mm
34mm
L5970D
8/10
APPLICATION IDEAS
Figure 16. Dual output voltage with auxiliary winding
Figure 17. Buck-Boost regulator
Figure 18. Positive Buck-Boost regul
Figure 19. Synchronization example
VIN=12V
C1
10uF
25V
Ceramic
D1
STPS25L25U
VCC
COMP
GND
OUT
FB
INH
SYNC VREF
L5970D
1
3
7
5
6
4
8
2
R3
4.7k
U1
C3
22nF
3.3V
VOUT=3.3V
0.5A
C2
220pF
VOUT1=5V
30mA
C5
47uF
10V
Lp=22uH
D2
1N4148
C4
100uF
10V
N1/N2=2
VIN=12V
C1
10uF
25V
Ceramic
D1
STPS2L25U
VCC
COMP
GND
OUT
FB
INH
SYNC VREF
1
3
7
5
6
4
8
2
R3
4.7k
U1
L1
33uH
2.7k
24k
C4
22nF
3.3V
C5
100uF
16V
L5970
VOUT=-12V/0.3A
C3
220pF
C2
10uF
35V
Ceramic
Vin=12V Vout=-12V Iout=0.5A Efficiency=81%
VIN=5V
C1
10uF
25V
Ceramic
D1
STPS2L25U
VCC
COMP
GND
OUT
FB
INH
SYNC VREF
L5970
1
3
7
5
6
4
8
2
R3
4.7k
U1
L1
33uH
24k
2.7k
C3
22nF
3.3V
C4
100uF
16V
VOUT=12V/0.3A
C2
220pF
D2
STPS2L25U
M1
STN4NE03L
Vin=5V Vout=12V Iout=0.3A Efficiency=76%
VCC
GND
OUT
FB
INH
SYNC VREF
1
3
7
5
6
4
8
2
L5970D
COMP
VCC
GND
OUT
FB
INH
SYNC VREF
1
3
7
5
6
4
8
2
L5970D
COMP
VIN
9/10
L5970D
DIM.
mm
inch
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
A
1.75
0.069
a1
0.1
0.25
0.004
0.010
a2
1.65
0.065
a3
0.65
0.85
0.026
0.033
b
0.35
0.48
0.014
0.019
b1
0.19
0.25
0.007
0.010
C
0.25
0.5
0.010
0.020
c1
45
(typ.)
D (1)
4.8
5.0
0.189
0.197
E
5.8
6.2
0.228
0.244
e
1.27
0.050
e3
3.81
0.150
F (1)
3.8
4.0
0.15
0.157
L
0.4
1.27
0.016
0.050
M
0.6
0.024
S
8
(max.)
(1) D and F do not include mold flash or protrusions. Mold flash or
potrusions shall not exceed 0.15mm (.006inch).
SO8
OUTLINE AND
MECHANICAL DATA
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
STMicroelectronics acknowledges the trademarks of all companies referred to in this document.
The ST logo is a registered trademark of STMicroelectronics
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L5970D