Datasheet
LT1767/LT1767-1.8/
LT1767-2.5/LT1767-3.3/LT1767-5
3
1767fb
For more information www.linear.com/LT1767
elecTrical characTerisTics
PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum Switch Current Limit T
A
= 0°C to 125°C
T
A
= < 0°C
1.5
1.3
2 3
3
A
A
Oscillator Frequency 3.3V < V
IN
< 25V
l
1.1
1.1
1.25 1.4
1.5
MHz
MHz
Switch On Voltage Drop I
SW
= –1.5A, 0°C ≤ T
A
≤ 125°C and –1.3A, T
A
< 0°C
l
330 400
500
mV
mV
V
IN
Undervoltage Lockout (Note 3)
l
2.47 2.6 2.73 V
V
IN
Supply Current V
FB
= V
NOM
+ 17%
l
1 1.3 mA
Shutdown Supply Current V
SHDN
= 0V, V
IN
= 25V, V
SW
= 0V
l
6 20
45
µA
µA
Feedback Voltage 3V < V
IN
< 25V, 0.4V < V
C
< 0.9V
(Note 3)
LT1767 (Adj)
l
1.182
1.176
1.2 1.218
1.224
V
V
LT1767-1.8
l
1.764 1.8 1.836 V
LT1767-2.5
l
2.45 2.5 2.55 V
LT1767-3.3
l
3.234 3.3 3.366 V
LT1767-5
l
4.9 5 5.1 V
FB Input Current LT1767 (Adj)
l
–0.25 –0.5 µA
FB Input Resistance LT1767-1.8
LT1767-2.5
LT1767-3.3
LT1767-5
l
l
l
l
10.5
14.7
19
29
15
21
27.5
42
21
30
39
60
kΩ
kΩ
kΩ
kΩ
Error Amp V
oltage Gain 0.4V < V
C
< 0.9V 150 350
Error Amp Transconductance ∆I
VC
= ±10µA
l
500 850 1300 µMho
V
C
Pin Source Current V
FB
= V
NOM
– 17%
l
80 120 160 µA
V
C
Pin Sink Current V
FB
= V
NOM
+ 17%
l
70 110 180 µA
V
C
Pin to Switch Current Transconductance 2.5 A/V
V
C
Pin Minimum Switching Threshold Duty Cycle = 0% 0.35 V
V
C
Pin 1.5A I
SW
Threshold 0.9 V
Maximum Switch Duty Cycle V
C
= 1.2V, I
SW
= 400mA
l
85
80
90 %
%
Minimum Boost V
oltage Above Switch I
SW
= –1.5A, 0°C ≤ T
A
≤ 125°C and –1.3A, T
A
< 0°C
l
1.8 2.7 V
Boost Current I
SW
= –0.5A (Note 4)
I
SW
= –1.5A, 0°C ≤ T
A
≤ 125°C and –1.3A, T
A
< 0°C (Note 4)
l
l
10
30
15
45
mA
mA
SHDN Threshold V
oltage
l
1.27 1.33 1.40 V
SHDN Input Current (Shutting Down) SHDN = 60mV Above Threshold
l
–7 –10 –13 µA
SHDN Threshold Current Hysteresis SHDN = 100mV Below Threshold
l
4 7 10 µA
SYNC Threshold Voltage 1.5 2.2 V
SYNC Input Frequency 1.5 2 MHz
SYNC Pin Resistance I
SYNC
= 1mA 20 kΩ
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V, V
C
= 0.8V, Boost = V
IN
+ 5V, SHDN, SYNC and switch open
unless otherwise noted.
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