Datasheet

LT1976/LT1976B
3
1976bfg
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
PK
SW Current Limit LT1976 ● 1.5 2.4 3.5 A
LT1976B 1.2 2.5 4 A
Switch On Resistance (Note 9) ● 0.2 0.4 Ω
Switching Frequency BOOST = OPEN ● 180 200 230 kHz
Maximum Duty Cycle 90 92 %
Minimum SYNC Amplitude 1.5 2.0 V
SYNC Frequency Range 230 600 kHz
SYNC Input Impedance SYNC = 0.5V 100 kΩ
I
CSS
C
SS
Current Threshold (Note 10) FB = 0V 7 13 20 μA
I
PGFB
PGFB Input Current 25 100 nA
V
PGFB
PGFB Voltage Threshold (Note 11) ● 88 90 92 %
I
CT
C
T
Source Current (Note 11) ● 2 3.6 5.5 μA
C
T
Sink Current (Note 11) 1 2 mA
V
CT
C
T
Voltage Threshold (Note 11) 1.16 1.2 1.26 V
PG Leakage (Note 11) PG = 12V 0.1 1 μA
PG Sink Current (Note 11) PGFB = 1V, PG = 400mV 120 200 μA
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full –40°C to 125°C
operating temperature range, otherwise specifications are at T
J
= 25°C. V
IN
= 12V, SHDN = 12V, BOOST = 15.3V, BIAS = 5V,
FB/PGFB = 1.25V, C
SS
/SYNC = 0V unless otherwise noted.
The ● denotes the specifications which apply over the full –40°C to 140°C operating temperature range, otherwise specifications are
at T
J
= 25°C. V
IN
= 12V, SHDN = 12V, BOOST = 15.3V, BIAS = 5V, FB/PGFB = 1.25V, C
SS
/SYNC = 0V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
SHDN
SHDN Threshold ● 1.2 1.3 1.4 V
I
SHDN
SHDN Input Current SHDN = 12V ● 520 μA
Minimum Input Voltage (Note 3) ● 2.4 3 V
I
VINS
Supply Shutdown Current SHDN = 0V, BOOST = 0V, FB/PGFB = 0V 0.1 2 μA
Supply Sleep Current (Note 4) (LT1976) BIAS = 0V, FB = 1.35V ● 170 300 μA
FB = 1.35V
● 45 100 μA
I
VIN
Supply Quiescent Current BIAS = 0V, FB = 1.15V, V
C
= 0.8V 3.2 4.10 mA
BIAS = 5V, FB = 1.15V, V
C
= 0.8V 2.6 3.25 mA
Minimum BIAS Voltage (Note 5) ● 2.7 3 V
I
BIASS
BIAS Sleep Current (Note 4) ● 110 180 μA
I
BIAS
BIAS Quiescent Current SYNC = 3.3V 700 800 μA
Minimum Boost Voltage (Note 6) I
SW
= 1.5A 1.8 2.5 V
Input Boost Current (Note 7) I
SW
= 1.5A 40 50 mA
V
REF
Reference Voltage (V
REF
) 3.3V < V
VIN
< 60V ● 1.212 1.25 1.288 V
I
FB
FB Input Bias Current 75 200 nA
EA Voltage Gain (Note 8) 900 V/V
EA Voltage g
m
dI(V
C
)= ±10μA 400 650 800 μMho
EA Source Current FB = 1.15V 20 40 55 μA
EA Sink Current FB = 1.35V 15 30 40 μA
V
C
to SW g
m
3A/V
V
C
High Clamp 2.1 2.2 2.4 V