Datasheet

LT3990/LT3990-3.3/LT3990-5
3
3990fa
ELECTRICAL CHARACTERISTICS
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 LT3990E 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
LT3990I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3990H 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.
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
BD
= 3.3V unless otherwise noted. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Input Voltage
l
4 4.2 V
Quiescent Current from V
IN
V
EN/UVLO
Low
V
EN/UVLO
High
V
EN/UVLO
High
l
0.7
1.9
1.2
2.8
4
µA
µA
µA
LT3990 Feedback Voltage
l
1.195
1.185
1.21
1.21
1.225
1.235
V
V
LT3990-3.3 Output Voltage
l
3.26
3.234
3.3
3.3
3.34
3.366
V
V
LT3990-5 Output Voltage
l
4.94
4.9
5
5
5.06
5.1
V
V
LT3990 FB Pin Bias Current (Note 3)
l
0.1 20 nA
FB/Output Voltage Line Regulation 4.2V < V
IN
< 40V 0.0002 0.01 %/V
Switching Frequency R
T
= 41.2k, V
IN
= 6V
R
T
= 158k, V
IN
= 6V
R
T
= 768k, V
IN
= 6V
1.84
672
168
2.3
840
210
2.76
1008
252
MHz
kHz
kHz
Switch Current Limit V
IN
= 5V, V
FB
= 0V 535 700 865 mA
Catch Schottky Current Limit V
IN
= 5V 360 450 540 mA
Switch V
CESAT
I
SW
= 200mA 210 mV
Switch Leakage Current 0.05 2 µA
Catch Schottky Forward Voltage I
SCH
= 100mA, V
IN
= V
BD
= NC 725 mV
Catch Schottky Reverse Leakage V
SW
= 12V 0.05 2 µA
Boost Schottky Forward Voltage I
SCH
= 50mA, V
IN
= NC, V
BOOST
= 0V 900 mV
Boost Schottky Reverse Leakage V
REVERSE
= 12V 0.02 2 µA
Minimum Boost Voltage (Note 4) V
IN
= 5V
l
1.4 1.8 V
BOOST Pin Current I
SW
= 200mA, V
BOOST
= 15V 8.5 12 mA
EN/UVLO Pin Current V
EN/UVLO
= 12V 1 30 nA
EN/UVLO Voltage Threshold EN/UVLO Rising, V
IN
≥ 4.2V
l
1.14 1.19 1.28 V
EN/UVLO Voltage Hysteresis 35 mV
PG Threshold Offset from Feedback Voltage V
FB
Rising 6.5 10 13.5 %
PG Hysteresis as % of Output Voltage 1.0 %
PG Leakage V
PG
= 3V 0.01 1 µA
PG Sink Current V
PG
= 0.4V
l
30 80 µA
Minimum Switch On-Time 115 ns
Minimum Switch Off-Time V
IN
= 10V
l
100 160 ns
Note 3: Bias current flows into the FB pin.
Note 4: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the switch.