LT1767 Linear Technology, LT1767 Datasheet - Page 3

• Manufacturer Part Number: LT1767
• Description: Monolithic 1.5A/ 1.25MHz Step-Down Switching Regulators
• Manufacturer: Linear Technology

ELECTRICAL CHARACTERISTICS
The
V
PARAMETER
FB Input Resistance
Error Amp Voltage Gain
Error Amp Transconductance
V
V
V
V
V
Maximum Switch Duty Cycle
Minimum Boost Voltage Above Switch
Boost Current
SHDN Threshold Voltage
SHDN Input Current (Shutting Down)
SHDN Threshold Current Hysteresis
SYNC Threshold Voltage
SYNC Input Frequency
SYNC Pin Resistance
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1767E is guaranteed to meet performance specifications
from 0 C to 125 C. Specifications over the – 40 C to 125 C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls.
TYPICAL PERFORMANCE CHARACTERISTICS
C
C
C
C
C
IN
Pin Source Current
Pin Sink Current
Pin to Switch Current Transconductance
Pin 1.5A I
Pin Minimum Switching Threshold
1.22
1.21
1.20
1.19
1.18
= 15V, V
–50
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
FB vs Temperature (Adj)
–25
SW
C
= 0.8V, Boost = V
Threshold
0
TEMPERATURE ( C)
25
50
IN
75
W
+ 5V, SHDN, SYNC and switch open unless otherwise noted.
100
U
1767 G01
CONDITION
LT1767-1.8
LT1767-2.5
LT1767-3.3
LT1767-5
0.4V < V
V
V
Duty Cycle = 0%
V
I
I
I
SHDN = 60mV Above Threshold
SHDN = 100mV Below Threshold
I
125
SW
SW
SW
SYNC
FB
FB
C
I
VC
= 1.2V, I
= V
= V
= –1.5A, 0 C T
= – 0.5A (Note 4)
= –1.5A, 0 C T
= 10 A
= 1mA
NOM
NOM
C
400
350
300
250
200
150
100
< 0.9V
50
SW
– 17%
+ 17%
0
0
Switch On Voltage Drop
= 400mA
A
A
SWITCH CURRENT (A)
125 C and –1.3A, T
125 C and –1.3A, T
0.5
LT1767-2.5/LT1767-3.3/LT1767-5
Note 3: Minimum input voltage is defined as the voltage where the internal
regulator enters lockout. Actual minimum input voltage to maintain a
regulated output will depend on output voltage and load current. See
Applications Information.
Note 4: Current flows into the BOOST pin only during the on period of the
switch cycle.
1
125 C
–40 C
A
A
25 C
< 0 C
< 0 C (Note 4)
1767 G02
1.5
LT1767/LT1767-1.8/
1.50
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
–50
Oscillator Frequency
10.5
14.7
1.27
MIN
150
500
1.5
–25
19
29
80
70
85
80
– 7
4
0
TEMPERATURE ( C)
27.5
0.35
1.33
TYP
–10
350
850
120
110
2.5
0.9
1.8
1.5
15
21
42
90
10
30
20
7
25
50
MAX
1300
1.40
160
180
–13
2.7
2.2
A
21
30
39
60
15
45
10
2
75
= 25 C.
sn1767 1767fas
100
UNITS
1767 G03
3
Mho
MHz
A/V
mA
mA
k
k
k
k
k
125
%
%
A
A
V
V
V
V
A
A
V