Datasheet
LT1950
4
1950fa
TEMPERATURE (°C)
–50
FB VOLTAGE (V)
1.26
1.25
1.24
1.23
1.22
1.21
1.20
25 75
1950 G01
–25 0
50 100 125
TEMPERATURE (°C)
–50
FREQUENCY (kHz)
1950 • G02
0
50
100
240
230
220
210
200
190
180
170
160
–25 25 75
125
TEMPERATURE (°C)
–50
V
IN
SHUTDOWN I
Q
(µA)
1950 • G03
0
50
100
16
14
12
10
8
6
4
2
0
–25 25 75
125
SHDN = 0V
TEMPERATURE (°C)
–50
SHUTDOWN THRESHOLD (V)
1950 • G04
0
50
100
1.45
1.40
1.35
1.30
1.25
1.20
–25 25 75
125
TEMPERATURE (°C)
–50
MAXIMUM I
SENSE
THRESHOLD (mV)
125
120
115
110
105
100
95
90
85
80
75
0
50
75
1950 G05
–25
25
100
125
I
SENSE
CURRENT (µA)
270
250
230
210
190
170
150
130
110
90
TEMPERATURE (°C)
–50 0
50
75
1950 G06
–25
25
100
125
PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum Duty Cycle Clamp V
SEC
= 1.4V, FB = 1V, COMP = V
OH
63 75 87 %
V
SEC
Input Bias Current 0V < V
SEC
< 2.8V –0.3 –1.0 µA
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1950EGN is guaranteed to meet performance specifications
from 0°C to 125°C operating junction temperature. Specifications over the
–40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LT1950IGN is guaranteed over the full –40°C to 125°C operating
junction temperature range.
Note 3: Rise and Fall times are between 10% and 90% levels.
FB Voltage vs Temperature
Switching Frequency vs
Temperature
V
IN
Shutdown I
Q
vs Temperature
Shutdown Threshold vs
Temperature
Maximum I
SENSE
Threshold vs
Temperature
I
SENSE
Pin Current vs
Temperature
ELECTRICAL CHARACTERISTICS
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Note 4: Guaranteed by correlation to static test.
Note 5: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 6: Guaranteed but not tested.
Note 7: Maximum recommended SYNC frequency = 500kHz.
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. COMP = open, FB = 1.4V, R
OSC
= 249k, SYNC = 0V, SLOPE = open, V
REF
= 0.1µF, SHDN = V
IN
, BLANK = 0V, I
SENSE
= 0V, V
IN2
= 15V, GATE = 1nF, BOOST = open, V
IN
= 15V, V
SEC
= 0V, unless otherwise
specified.