LT1766/LT1766-5
5
1766fc
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
f
SW
Line Regulation 5.5V ≤ V
IN
≤ 60V
l
0.05 0.15 %/V
f
SW
Frequency Shifting Threshold Df = 10kHz 0.8 V
Minimum Input Voltage (Note 3)
l
4.6 5.5 V
Minimum Boost Voltage (Note 4) I
SW
≤ 0.75A
l
1.8 3 V
Boost Current (Note 5) Boost = V
IN
+ 5V, I
SW
= 0.5A
Boost = V
IN
+ 5V, I
SW
= 0.75A
l
l
12
45
40
100
mA
mA
Input Supply Current (I
VIN
) (Note 6) V
BIAS
= 5V 1.4 2.2 mA
Bias Supply Current (I
BIAS
) (Note 6) V
BIAS
= 5V 2.9 4.2 mA
Shutdown Supply Current SHDN = 0V, V
IN
≤ 60V, SW = 0V, V
C
Open
l
25 120
500
μA
μA
Lockout Threshold V
C
Open
l
2.3 2.42 2.68 V
Shutdown Thresholds V
C
Open, Shutting Down
V
C
Open, Starting Up
l
l
0.15
0.25
0.37
0.45
0.9
0.9
V
V
Minimum SYNC Amplitude
l
1.5 2.2 V
SYNC Frequency Range 228 700 kHz
SYNC Input Resistance 20 kΩ
(LT1766H Grade)
The
l denotes specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T
J
= 25°C.
V
IN
= 15V, V
C
= 1.5V, SHDN = 1V, BOOST open circuit, SW open circuit, unless otherwise noted.
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: Gain is measured with a V
C
swing equal to 200mV above the low
clamp level to 200mV below the upper clamp level.
Note 3: Minimum input voltage is not measured directly, but is guaranteed
by other tests. It is defi ned as the voltage where internal bias lines are still
regulated so that the reference voltage and oscillator remain constant.
Actual minimum input voltage to maintain a regulated output will depend
upon output voltage and load current. See Applications Information.
Note 4: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
Note 5: Boost current is the current fl owing into the BOOST pin with the
pin held 5V above input voltage. It fl ows only during switch on time.
Note 6: Input supply current is the quiescent current drawn by the input
pin when the BIAS pin is held at 5V with switching disabled. Bias supply
current is the current drawn by the BIAS pin when the BIAS pin is held
at 5V. Total input referred supply current is calculated by summing input
supply current (I
VIN
) with a fraction of bias supply current (I
BIAS
):
I
TOTAL
= I
VIN
+ (I
BIAS
)(V
OUT
/V
IN
)
with V
IN
= 15V, V
OUT
= 5V, I
VIN
= 1.4mA, I
BIAS
= 2.9mA, I
TOTAL
= 2.4mA.
Note 7: Switch on-resistance is calculated by dividing V
IN
to SW voltage
by the forced current. See Typical Performance Characteristics for the
graph of switch voltage at other currents.
Note 8: The LT1766EGN, LT1766EGN-5, LT1766EFE and LT1766EFE-5
are 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 LT1766IGN, LT1766IGN-5,
LT1766IFE and LT1766IFE-5 are guaranteed over the full –40°C to 125°C
operating junction temperature range. The LT1766HGN and LT1766HFE are
guaranteed over the full –40°C to 140°C operating junction temperature
range.
Note 9: Transconductance and voltage gain refer to the internal amplifi er
exclusive of the voltage divider. To calculate gain and transconductance,
refer to the SENSE pin on fi xed voltage parts. Divide the values shown by
the ratio V
OUT
/1.219.
Note 10: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 140°C when overtemperature protection is active.
Continuous operation above the specifi ed maximum operating junction
temperature may impair device reliability.
Note 11: High junction temperatures degrade operating lifetimes.
Operating lifetime at junction temperatures between 125°C and 140°C is
derated to 1000 hours.
