LT1676CS8 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LT1676CS8' PDF : 16 Pages View PDF
LT1676
ELECTRICAL CHARACTERISTICS
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C.
VIN = 48V, VSW open, VCC = 5V, VC = 1.4V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
Timing
f
Switching Frequency
90
100
110
kHz
q 85
115
kHz
Maximum Switch Duty Cycle
q 85
90
%
tON(MIN)
Minimum Switch On Time
Boost Operation
High dV/dt Mode, RL = 50Ω (Note 4)
300
ns
VC Pin Boost Threshold
dV/dt Below Threshold
1.35
V
0.2
V/ns
dV/dt Above Threshold
1.6
V/ns
Sync Function
Minimum Sync Amplitude
q
1.5
2.2
V
Synchronization Range
q 130
250
kHz
SYNC Pin Input R
40
kΩ
SHDN Pin Function
VSHDN
Shutdown Mode Threshold
0.5
V
q 0.2
0.8
V
Upper Lockout Threshold
Switching Action On
1.260
V
Lower Lockout Threshold
Switching Action Off
1.245
V
ISHDN
Shutdown Pin Current
VSHDN = 0V
VSHDN = 1.25V
12
20
µA
2.5
10
µA
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Control circuitry powered from VCC.
Note 3: Switch current limit is DC trimmed and tested in production.
Inductor dl/dt rate will cause a somewhat higher current limit in actual
application.
Note 4: Minimum switch on time is production tested with a 50Ω resistive
load to ground.
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Input Voltage vs
Temperature
7.4
7.2
7.0
6.8
6.6
6.4
6.2
6.0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
LT1676 G01
Switch-On Voltage vs
Switch Current
1.50
1.25
25°C
1.00
– 55°C
0.75
125°C
0.50
0.25
0
0 100 200 300 400 500 600 700
SWITCH CURRENT (mA)
1676 G02
Switch Current Limit vs
Duty Cycle
1000
TA = 25°C
800
600
400
200
0
0 10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
1676 G03
3
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