AN937 Datasheet, PDF (3/29 Pages) STMicroelectronics – The L4971 is a 1.5 A monolithic dc-dc converter

AN937
1
Device description
Device description
For a better understanding of the device and it’s working principle, a short description of the
main building blocks is given here below, with packaging options and complete block
diagram.
Figure 2 show s the two packaging options, with the pin function assignments.
Figure 2. Pin Connections
GND
SS_INH
OSC
OUT
1
8
2
7
3
6
4
5
D97IN595
FB
COMP
BOOT
VCC
DIP8
N.C.
GND
SS_INH
OSC
OUT
OUT
N.C.
N.C.
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
D97IN596
SO16L
N.C.
N.C.
FB
COMP
BOOT
VCC
N.C.
N.C.
Figure 3. Block diagram.
THERMAL
SHUTDOWN
VOLTAGES
MONITOR
2
SS_INH
INHIBIT
7
COMP
8
E/A
FB
3.3V
SOFTSTART
3.3V
INTERNAL
REFERENCE
PWM
R
Q
S
OSCILLATOR
3
OSC
1
GND
VCC
5
INTERNAL
SUPPLY _5.1V
DRIVE
CBOOT
CHARGE
6
BOOT
CBOOT
CHARGE
AT LIGHT
LOADS
4
OUT
D97IN594
Doc ID 5655 Rev 15
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