LT3976
3
3976f
For more information www.linear.com/3976
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Input Voltage (Note 3)
l
4 4.3 V
Dropout Comparator Threshold (V
IN
– OUT) Falling 430 500 570 mV
Dropout Comparator Threshold Hysteresis 25 mV
Quiescent Current from V
IN
V
EN
Low
V
EN
High, V
SYNC
Low
V
EN
High, V
SYNC
Low
l
0.7
1.6
1.3
2.7
30
µA
µA
µA
FB Pin Current V
FB
= 1.5V
l
0.1 12 nA
Feedback Voltage
l
1.183
1.173
1.197
1.197
1.212
1.222
V
V
FB Voltage Line Regulation 4.3V < V
IN
< 40V (Note 3) 0.0003 0.01 %/V
Switching Frequency R
T
= 11.8k
R
T
= 41.2k
R
T
= 294k
1.8
0.8
160
2.25
1
200
2.7
1.2
240
MHz
MHz
kHz
Minimum Switch On-Time 120 ns
Minimum Switch Off-Time (Note 4) 150 200 ns
Switch Current Limit V
FB
= 1V 7.5 10 12.5 A
Foldback Switch Current Limit V
FB
= 0V 4.8 A
Switch V
CESAT
I
SW
= 1A 80 mV
Switch Leakage Current 0.02 1 μA
Boost Schottky Forward Voltage I
SH
= 100mA 730 mV
Boost Schottky Reverse Leakage V
REVERSE
= 12V 0.02 2 μA
Minimum Boost Voltage (Note 5)
l
1.3 1.8 V
BOOST Pin Current I
SW
= 1A, V
BOOST
– V
SW
= 3V 20 32 mA
EN Voltage Threshold EN Falling, V
IN
≥ 4.3V
l
0.92 1.02 1.12 V
EN Voltage Hysteresis 60 mV
EN Pin Current 0.2 20 nA
PG Threshold Offset from V
FB
V
FB
Falling 5 8.4 13 %
PG Hysteresis as % of Output Voltage 1.7 %
PG Leakage V
PG
= 3V 0.02 1 µA
PG Sink Current V
PG
= 0.4V
l
125 480 μA
SYNC Low Threshold 0.6 1.0 V
SYNC High Threshold 1.18 1.5 V
SYNC Pin Current V
SYNC
= 6V 0.1 nA
SS Source Current V
SS
= 0.5V 0.9 1.8 2.6 μA
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 LT3976E 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
LT3976I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3976H 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 junction temperature (T
J
, in °C) is
calculated from the ambient temperature (T
A
, in °C) and power dissipation
(P
D
, in Watts) according to the formula:
T
J
= T
A
+ (P
D
• θ
JA
)
where θ
JA
(in °C/W) is the package thermal impedance.
