Datasheet

LT3505
3
3505fc
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 LT3505E is guaranteed to meet performance specifi cations
from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls. The LT3505I specifi cations are
guaranteed over the –40°C to 125°C temperature range.
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Operating Range 3.6 36 V
Undervoltage Lockout 3.1 3.35 3.6 V
Feedback Voltage
"
765 780 795 mV
FB Pin Bias Current V
FB
= Measured V
REF
(Note 4)
"
55 150 nA
Quiescent Current Not Switching, R
T
= 75.0k 2.0 2.7 mA
Quiescent Current in Shutdown V
SHDN
= 0V 0.01 2 µA
Reference Line Regulation V
IN
= 5V to 36V 0.007 %/V
Switching Frequency V
FB
= 0.7V, R
T
= 13.7k
V
FB
= 0.7V, R
T
= 75.0k
V
FB
= 0.7V, R
T
= 357k
2.70
675
180
3.01
750
200
3.30
825
220
MHz
kHz
kHz
Maximum Duty Cycle R
T
= 75.0k
"
90 94 %
Error Amp Transconductance V
FB
= 0.78V 200 µA/V
Error Amp Voltage Gain V
FB
= 0.78V 400 V/V
V
C
Source Current V
FB
= 0V, V
C
= 1.5V 10 µA
V
C
Sink Current V
FB
= 1V, V
C
= 1.5V 14 µA
V
C
Switching Threshold Voltage I
OUT
= 0mA 0.9 V
V
C
Clamp Voltage V
FB
= 0V 1.7 V
R
T
Bias Voltage V
FB
= 0.6V
V
FB
= 0V, R
T
= 75.0k
0.5
50
V
mV
Switch Current Limit (Note 3) 1.4 1.75 2.2 A
Switch V
CESAT
I
SW
= 1A 350 mV
Switch Leakage Current 0.1 2 µA
Minimum Boost Voltage Above Switch I
SW
= 1A 1.6 2.2 V
BOOST Pin Current I
SW
= 1A 24 50 mA
SHDN Input Voltage High 2.3 V
SHDN Input Voltage Low 0.3 V
SHDN Bias Current V
SHDN
= 2.3V (Note 5)
V
SHDN
= 0V
6
0.01
20
0.1
µA
µA
ELECTRICAL CHARACTERISTICS
The " denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C, V
IN
= 12V, V
BOOST
= 17V, unless otherwise noted. (Note 2).
Note 3: Current limit guaranteed by design and/or correlation to static test.
Slope compensation reduces current limit at higher duty cycle.
Note 4: Current fl ows out of pin.
Note 5: Current fl ows into pin.