Datasheet
LT3478/LT3478-1
2
34781f
SW ............................................................................42V
V
OUT
, LED ..................................................................42V
V
IN
, V
S
, V
L
,
⎯
S
⎯
H
⎯
D
⎯
N (Note 5) .......................................36V
PWM .........................................................................15V
CTRL1, 2 .....................................................................6V
SS, R
T
, V
C
, V
REF
, OVPSET ............................................2V
Operating Junction Temperature Range
(Notes 2, 3, 4) .................................... –40°C to 125°C
Storage Temperature Range ................... –65°C to 150°C
Lead Temperature (Soldering, 10 Sec) .................. 300°C
(Note 1)
The
● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. SW = open, V
IN
= V
S
= L = V
OUT
=
⎯
S
⎯
H
⎯
D
⎯
N = 2.7V, LED = open, SS = open,
PWM = CTRL1, CTRL2 = 1.25V, V
REF
= open, V
C
= open, R
T
= 31.6k.
ELECTRICAL CHARACTERISTICS
ABSOLUTE AXI U RATI GS
W
WW
U
PACKAGE/ORDER I FOR ATIO
UUW
FE PACKAGE
16-LEAD PLASTIC TSSOP
1
2
3
4
5
6
7
8
TOP VIEW
16
15
14
13
12
11
10
9
17
SW
SW
V
IN
V
S
L
V
OUT
LED
OVPSET
SS
R
T
PWM
CTRL2
CTRL1
SHDN
V
REF
V
C
T
JMAX
= 125°C, θ
JA
= 35°C/W
EXPOSED PAD (PIN 17) IS PGND, MUST BE SOLDERED TO PCB.
ORDER PART NUMBER FE PART MARKING
LT3478EFE
LT3478EFE-1
LT3478IFE
LT3478IFE-1
3478FE
3478FE-1
3478FE
3478FE-1
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage (Rising)
●
2.4 2.8 V
Operational Input Voltage V
S
V
IN
(Note 5)
2.8
2.8
36
36
V
V
V
IN
Quiescent Current V
C
= 0V (No Switching) 6.1 mA
V
IN
Shutdown Current
⎯
S
⎯
H
⎯
D
⎯
N = 0V 3 6 µA
⎯
S
⎯
H
⎯
D
⎯
N Pin Threshold (V
SD_µp
) (Micropower)
●
0.1 0.4 0.7 V
⎯
S
⎯
H
⎯
D
⎯
N Pin Threshold (V
SD_UVLO
) (Switching) 1.3 1.4 1.5 V
⎯
S
⎯
H
⎯
D
⎯
N Pin Current
⎯
S
⎯
H
⎯
D
⎯
N = V
SD_UVLO
– 50mV
⎯
S
⎯
H
⎯
D
⎯
N = V
SD_UVLO
+ 50mV
810
0
12 µA
µA
V
REF
Voltage I(V
REF
) = 0µA, V
C
= 0V
●
1.213 1.240 1.263 V
V
REF
Line Regulation I(V
REF
) = 0µA, 2.7V < V
IN
< 36V 0.005 0.015 %/V
V
REF
Load Regulation 0 < I(V
REF
) < 100µA (Max) 8 12 mV
Frequency: f
OSC
200kHz R
T
= 200k 0.18 0.2 0.22 MHz
Frequency: f
OSC
1MHz R
T
= 31.6k
●
0.88 1.12 MHz