LT3508 LINER [Linear Technology], LT3508 Datasheet - Page 3

• Manufacturer Part Number: LT3508
• Description: Dual Monolithic 1.4A Step-Down Switching Regulator
• Manufacturer: LINER [Linear Technology]

ELECTRICAL CHARACTERISTICS
PARAMETER
Minimum Operating Voltage, V
Minimum Operating Voltage, V
V
V
Shutdown Current (V
FB Voltage
FB Pin Bias Current (Note 3)
FB Voltage Line Regulation
Error Amp Transconductance
Error Amp Voltage Gain
V
Switching Frequency
Switching Phase
Maximum Duty Cycle (Note 4)
Foldback Frequency
Switch Current Limit (Note 5)
Switch V
Switch Leakage Current
Minimum Boost Voltage
Boost Pin Current
TRACK/SS Pin Current
PG Threshold Offset
PG Voltage Output Low
PG Pin Leakage
SHDN Threshold Voltage
SHDN Input Current (Note 6)
SHDN Threshold Current Hysteresis
SYNC Threshold Voltage
SYNC Input Frequency
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 LT3508E is guaranteed to meet performance specifi cations
from 0°C to 125°C junction temperature. Specifi cations over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT3508I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3508H is guaranteed over the full –40°C to
150°C operating junction temperature range. High junction temperatures
degrade operating lifetimes. Operating lifetime is derated at junction
temperatures greater than 125°C.
temperature range, otherwise specifi cations are at T
IN1
IN2
C
to Switch Current Gain
Quiescent Current
Quiescent Current
CESAT
IN1
+ V
IN2
IN1
IN2
)
CONDITIONS
V
Not Switching
Not Switching
V
V
5V < V
R
R
R
R
R
R
Duty Cycle = 15%
I
I
V
V
V
V
V
SW
SW
TRACK/SS
IN1
SHDN
FB
T
T
T
T
T
T
FB
FB
PG
SHDN
= 33.2k
= 33.2k
= 33.2k
= 7.50k
= 169k
= 33.2k, V
= 0.800V, V
= 1.5A
= 1.5A
Rising
= 0.6V, I
= 2V
= 12V
IN
= 0.3V
= 60mV Above Threshold Voltage
A
< 40V
= 25°C. V
= 0V
PG
FB
The
= 250μA
C
= 0V
= 0.4V
l
IN
denotes the specifi cations which apply over the full operating
= 12V, V
Note 3: Current fl ows out of pin.
Note 4: V
LT3508 when V
the Applications Information section for details.
Note 5: Current limit is guaranteed by design and/or correlation to static
test. Slope compensation reduces current limit at higher duty cycles.
Note 6: Current fl ows into pin.
Note 7: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed the maximum operating junction temperature
range when overtemperature protection is active. Continuous operation
above the specifi ed maximum operating junction temperature may impair
device reliability.
BOOST
BOOST
= 17V unless otherwise noted. (Note 2)
BOOST
=12V. Circuitry increases the maximum duty cycle of the
> V
IN
+ 2.5V. See “Minimum Operating Voltage” in
l
l
l
l
l
l
l
0.790
0.784
MIN
0.92
2.53
0.25
150
2.0
0.8
5.5
84
56
6
1
0.800
0.01
0.01
0.13
0.01
2.63
1.25
TYP
320
300
600
180
120
300
3.4
2.5
4.3
0.1
2.5
2.6
1.7
1.2
7.5
50
90
80
98
35
75
1
8
LT3508
0.814
0.816
MAX
1.06
2.73
500
300
210
110
3.7
3.0
5.2
3.2
2.5
2.2
0.4
9.5
1.5
2.5
50
10
2
1
1
UNITS
3508fb
3
MHz
MHz
%/V
Deg
kHz
V/V
A/V
mA
mV
mA
mV
μA
μA
nA
μS
μA
μA
μA
μA
μA
%
%
%
V
V
V
V
A
V
V
V
V