2
LT1425
ABSOLUTE
M
AXI
M
U
M
RATINGS
W
W
W
U
PACKAGE/ORDER I
N
FOR
M
ATIO
N
W
U
U
T
JMAX
= 145
°
C,
θ
JA
= 75
°
C/ W
TOP VIEW
S PACKAGE
16-LEAD PLASTIC SO
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
GND
NC
R
FB
V
C
R
REF
SYNC
SGND
GND
GND
SHDN
R
OCOMP
R
CCOMP
V
IN
V
SW
PGND
GND
ORDER PART
NUMBER
LT1425CS
LT1425IS
ELECTRICAL CHARACTERISTICS
V
IN
= 5V, T
J
= 25
°
C, V
SW
open, V
C
= 1.4V, unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Feedback Amplifier
I
REF
Reference Current
Measured at R
FB
Pin with R
REF
= 3.000k
402
408
414
µ
A
●
396
420
µ
A
I
IN
R
REF
Pin Input Current
500
nA
g
m
Feedback Amplifier Transconductance
∆
I
C
=
±
10
µ
A (Note 2)
●
400
1000
1600
µ
mho
I
SOURCE
, I
SINK
Feedback Amplifier Source or Sink Current
●
30
50
80
µ
A
V
CL
Feedback Amplifier Clamp Voltage
1.9
V
Reference Voltage/Current Line Regulation
5V
≤
V
IN
≤
18V
●
0.01
0.04
%/V
Voltage Gain
(Note 3)
500
V/V
V
IN
Sense Error
●
10
25
mV
Output Switch
BV
Output Switch Breakdown Voltage
I
C
= 5mA
●
35
50
V
V(V
SW
)
Output Switch ON Voltage
I
SW
= 1A
●
0.55
0.85
V
I
LIM
Switch Current Limit
Duty Cycle = 50%, 0
°
C
≤
T
J
≤
100
°
C
●
1.35
1.60
1.9
A
Duty Cycle = 50%, – 40
°
C
≤
T
J
≤
100
°
C
●
1.25
1.60
1.9
A
Duty Cycle = 80%
1.30
A
Current Amplifier
Control Pin Threshold
Duty Cycle = Minimum
0.95
1.2
1.3
V
●
0.85
1.4
V
Control Voltage to Switch Transconductance
2
A/V
Timing
f
Switching Frequency
260
285
300
kHz
●
240
320
kHz
t
ON
Minimum Switch ON Time
170
210
260
ns
t
ED
Flyback Enable Delay Time
150
ns
t
EN
Minimum Flyback Enable Time
180
ns
Maximum Switch Duty Cycle
●
85
90
95
%
Consult factory for Military grade parts.
(Note 1)
Supply Voltage ........................................................ 20V
Switch Voltage ......................................................... 35V
SHDN, SYNC Pin Voltage ........................................... 7V
R
FB
Pin Current....................................................... 2mA
Operating Junction Temperature Range
Commercial .......................................... 0
°
C to 100
°
C
Industrial ......................................... – 40
°
C to 100
°
C
Storage Temperature Range ................. – 65
°
C to 150
°
C
Lead Temperature (Soldering, 10 sec).................. 300
°
C