Datasheet

LT3477
6
3477fc
PIN FUNCTIONS
(QFN/TSSOP)
I
SP2
(Pin 13/Pin 11): Second Current Sense (+) Pin. The
noninverting input to the second current sense amplifi er.
Connect to I
SN2
if not used.
I
SN2
(Pin 14/Pin 12): Second Current Sense (–) Pin. The
inverting input to the second current sense amplifi er.
Connect to I
SP2
if not used.
I
SP1
(Pin 15/Pin 13): First Current Sense (+) Pin. The
noninverting input to the fi rst current sense amplifi er.
Connect to I
SN1
if not used.
I
SN1
(Pin 16/Pin 14): First Current Sense (–) Pin. The in-
verting input to the fi rst current sense amplifi er. Connect
to I
SP1
if not used.
GND (Pins 17/Pin 15): Ground. Tie directly to local
ground plane.
SW (Pins 18, 19/Pins 16, 17): Switch Pins. Collector of
the internal NPN power switch. Connect the inductor and
diode here and minimize the metal trace area connected
to this pin to minimize electromagnetic interference.
Exposed Pad (Pin 21/Pin 21): Power Ground. Must be
soldered to PCB ground for electrical contact and rated
thermal performance.
–
+
–
+
–
+
∑
–
+
+
IA1
I
SP1
I
SN1
A1
V
C
SWSS
A3
A4
SLOPE
V
ADJ
I
ADJ1
I
SP2
I
SN2
FBP
FBN
SHDN
I
ADJ2
V
REF
–
+
–
+
+
IA2
–
+
R
T
V
IN
VA
A2V
ADJ
V
REF
1.25V
S
RQ1
3477 F01
Q
OSCILLATOR
Figure 1. LT3477 Block Diagram
BLOCK DIAGRAM