LT1374
ELECTRICAL CHARACTERISTICS
PARAMETER
Feedback Voltage (Adjustable)
Sense Voltage (Fixed 5V)
All Conditions
SENSE Pin Resistance
Reference Voltage Line Regulation
Feedback Input Bias Current
Error Amplifier Voltage Gain
Error Amplifier Transconductance
V
C
Pin to Switch Current Transconductance
Error Amplifier Source Current
Error Amplifier Sink Current
V
C
Pin Switching Threshold
V
C
Pin High Clamp
Switch Current Limit
Slope Compensation (Note 9)
Switch On Resistance (Note 7)
Maximum Switch Duty Cycle
Switch Frequency
Switch Frequency Line Regulation
Frequency Shifting Threshold on FB Pin
Minimum Input Voltage (Note 3)
Minimum Boost Voltage (Note 4)
Boost Current (Note 5)
V
IN
Supply Current (Note 6)
BIAS Supply Current (Note 6)
Shutdown Supply Current
CONDITIONS
All Conditions
The
q
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
J
= 25°C. V
IN
= 15V, V
C
= 1.5V, Boost = V
IN
+ 5V, switch open, unless otherwise noted.
MIN
2.39
2.36
4.94
4.90
7
TYP
2.42
5.0
10
0.01
0.5
400
2000
5.3
225
225
0.9
2.1
6
0.8
0.07
93
93
500
0
1.0
5.0
2.3
20
90
0.9
3.2
20
30
q
q
q
q
q
q
q
5V
≤
V
IN
≤
25V (5V
≤
V
IN
≤
32V for LT1374HV)
q
MAX
2.45
2.48
5.06
5.10
14
0.03
2
2700
3100
320
320
UNITS
V
V
V
V
kΩ
%/V
µA
µMho
µMho
A/ V
µA
µA
V
V
A
A
Ω
Ω
%
%
kHz
kHz
%/ V
V
V
V
mA
mA
mA
mA
µA
µA
µA
µA
V
V
V
V
kHz
kΩ
(Notes 2, 8)
∆I
(V
C
) =
±10µA
(Note 8)
q
200
1500
1000
140
140
V
FB
= 2.1V or V
SENSE
= 4.4V
V
FB
= 2.7V or V
SENSE
= 5.6V
Duty Cycle = 0
V
C
Open, V
FB
= 2.1V or V
SENSE
= 4.4V, DC
≤
50%
DC = 80%
I
SW
= 4.5A
V
FB
= 2.1V or V
SENSE
= 4.4V
q
q
q
4.5
8.5
0.1
0.13
q
q
V
C
Set to Give 50% Duty Cycle
q
90
86
460
440
0.8
5V
≤
V
IN
≤
25V, (5V
≤
V
IN
≤
32V for LT1374HV)
∆f
= 10kHz
I
SW
≤
4.5A
I
SW
= 1A
I
SW
= 4.5A
V
BIAS
= 5V
V
BIAS
= 5V
V
SHDN
= 0V, V
IN
≤
25V, V
SW
= 0V, V
C
Open
V
SHDN
= 0V, V
IN
≤
32V, V
SW
= 0V, V
C
Open
q
q
q
q
q
q
q
q
q
Lockout Threshold
Shutdown Thresholds
Synchronization Threshold
Synchronizing Range
SYNC Pin Input Resistance
V
C
Open
V
C
Open Device Shutting Down
Device Starting Up
2.3
0.13
0.25
580
2.38
0.37
0.45
1.5
40
540
560
0.15
1.3
5.5
3.0
35
140
1.4
4.0
50
75
75
100
2.46
0.60
0.7
2.2
1000
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
Gain is measured with a V
C
swing equal to 200mV above the
switching threshold level to 200mV below the upper clamp level.
Note 3:
Minimum input voltage is not measured directly, but is guaranteed
by other tests. It is defined as the voltage where internal bias lines are still
regulated so that the reference voltage and oscillator frequency remain
constant. Actual minimum input voltage to maintain a regulated output will
depend on output voltage and load current. See Applications Information.
Note 4:
This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
1374fb
3
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