LT8580
3
8580fa
For more information www.linear.com/LT8580
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LT8580E is guaranteed to meet performance specifications
from 0°C to 125°C 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
LT8580I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT8580H is guaranteed over the full –40°C to
150°C operating junction temperature range. Operating lifetime is derated
at junction temperatures greater than 125°C.
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, V
SHDN
= V
IN
unless otherwise noted. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range LT8580E, LT8580I
LT8580H
l
l
2.55
2.9
40
40
V
V
Positive Feedback Voltage
l
1.185 1.204 1.220 V
Negative Feedback Voltage
l
–3 3 12 mV
Positive FBX Pin Bias Current V
FBX
= Positive Feedback Voltage, Current Into Pin
l
81 83.3 85 µA
Negative FBX Pin Bias Current V
FBX
= Negative Feedback Voltage, Current Out of Pin
l
81 83.3 86 µA
Error Amplifier Transconductance
200 µmhos
Error Amplifier Voltage Gain 60 V/V
Quiescent Current V
SHDN
= 2.5V, Not Switching 1.2 1.7 mA
Quiescent Current in Shutdown V
SHDN
= 0V 0 1 µA
Reference Line Regulation 2.5V ≤ V
IN
≤ 40V 0.01 0.05 %/V
Switching Frequency, f
OSC
R
T
= 56.2k
R
T
= 422k
l
l
1.23
165
1.5
200
1.77
235
MHz
kHz
Switching Frequency in Foldback Compared to Normal f
OSC
1/6 Ratio
Switching Frequency Set Range SYNCing or Free Running
l
200 1500 kHz
SYNC High Level for Synchronization
l
1.3 V
SYNC Low Level for Synchronization
l
0.4 V
SYNC Clock Pulse Duty Cycle V
SYNC
= 0V to 2V 35 65 %
Recommended Minimum SYNC Ratio f
SYNC
/f
OSC
3/4
Minimum Off-Time 100 ns
Minimum On-Time 120 ns
Switch Current Limit Minimum Duty Cycle (Note 3)
Maximum Duty Cycle (Notes 3, 4), f
OSC
= 1.5MHz
Maximum Duty Cycle (Notes 3, 4), f
OSC
= 200kHz
l
l
l
1.2
0.6
0.4
1.5
1
0.8
1.8
1.5
1.4
A
A
A
Switch V
CESAT
I
SW
= 0.75A 400 mV
Switch Leakage Current V
SW
= 5V 0.01 1 µA
Soft-Start Charging Current V
SS
= 0.5V
l
4 6 8 µA
SHDN Minimum Input
Voltage High
Active Mode, SHDN
Rising
Active Mode, SHDN Falling
l
l
1.23
1.21
1.31
1.27
1.4
1.33
V
V
SHDN Input V
oltage Low Shutdown Mode
l
0.3 V
SHDN Pin Bias Current V
SHDN
= 3V
V
SHDN
= 1.3V
V
SHDN
= 0V
9
44
12
0
56
15
0.1
µA
µA
µA
SHDN Hysteresis 40 mV
Note 3: Current limit guaranteed by design and/or correlation to static test.
Note 4: Current limit measured at equivalent of listed switching frequency.
Note 5: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 150°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
