LM3485
Absolute Maximum Ratings
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
VIN Voltage
PGATE Voltage
FB Voltage
ISENSE Voltage
ADJ Voltage
Maximum Junction Temp.
Power Dissipation
−0.3V to 36V
−0.3V to 36V
−0.3V to 5V
−1.0V to 36V
−0.3V to 36V
150˚C
417mW
@
T
A
=
25˚C
ESD Susceptibilty
Human Body Model (Note 3)
Lead Temperature
Vapor Phase (60 sec.)
Infared (15 sec.)
Storage Temperature
2kV
215˚C
220˚C
−65˚C to 150˚C
Operating Ratings
Supply Voltage
Operating Junction
Temperature
4.5V to 35V
−40˚C to +125˚C
Electrical Characteristics
Specifications in Standard type face are for T
J
= 25˚C, and in
bold type face
apply over the full
Operating Temperature
Range
(T
J
= −40˚C to +125˚C). Unless otherwise specified, V
IN
= 12V, V
ISNS
= V
IN
− 1V, and V
ADJ
= V
IN
− 1.1V. Datasheet
min/max specification limits are guaranteed by design, test, or statistical analysis.
Symbol
I
Q
V
FB
V
HYST
V
CL
Parameter
Quiescent Current at
ground pin
Feedback Voltage
Comparator
Hysteresis
Current limit
comparator trip
voltage
Current limit
comparator offset
Current limit ADJ
current source
Current limit one shot
off time
Driver resistance
R
ADJ
= 20kΩ
R
ADJ
= 160kΩ
V
FB
= 1.5V
V
FB
= 1.5V
V
ADJ
= 11.5V
V
ISNS
= 11.0V
V
FB
= 1.0V
Source
I
SOURCE
= 100mA
Sink
I
Sink
= 100mA
I
PGATE
Driver Output current
Source
V
IN
= 7V,
P
GATE
= 3.5V
Sink
V
IN
= 7V,
P
GATE
= 3.5V
V
PGATEMIN
Minimum driver
voltage
FB pin Bias Current
Minimum on time in
normal operation
V
IN
= 4.5V
V
FB
= 1.0V
I
GATE
= 100µA sink
V
FB
= 1.0V
V
ISNS
= V
ADJ
+0.1V
C
load
on OUT =
1000pF
−20
3.0
6
Conditions
FB = 1.5V
(Not Switching)
1.226
1.217
Min
Typ
250
1.242
10
14
110
880
0
5.5
9
+20
7.0
14
mV
µA
µs
Max
400
1.258
1.267
15
20
Unit
µA
V
mV
mV
V
CL_OFFSET
I
CL_ADJ
T
CL
R
PGATE
5.5
8.5
0.44
Ω
A
0.32
1.2
V
I
FB
T
ONMIN_NOR
300
100
750
nA
ns
3
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