LT3430/LT3430-1
3
34301fa
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.
ELECTRICAL CHARACTERISTICS
The ● denotes the 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,
⎯
S
⎯
H
⎯
D
⎯
N = 1V, BOOST = Open Circuit,
SW = Open Circuit, unless otherwise noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum Switch Duty Cycle (LT3430-1)
●
96
94
98 %
%
Switch Frequency (LT3430) V
C
Set to Give DC = 50%
●
184
172
200
200
216
228
kHz
kHz
Switch Frequency (LT3430-1)
●
88
85
100
100
115
120
kHz
kHz
f
SW
Line Regulation 5.5V ≤ V
IN
≤ 60V
●
0.05 0.15 %/V
f
SW
Shifting Threshold Df = 10kHz 0.8 V
Minimum Input Voltage (Note 3)
●
4.6 5.5 V
Minimum Boost Voltage (Note 4) I
SW
≤ 2.5A
●
1.8 3 V
Boost Current (Note 5) Boost = V
IN
+ 5V, I
SW
= 0.75A
Boost = V
IN
+ 5V, I
SW
= 2.5A
●
●
25
75
50
120
mA
mA
Input Supply Current (I
VIN
) (Note 6) V
BIAS
= 5V 1.5 2.2 mA
Bias Supply Current (I
BIAS
) (Note 6) V
BIAS
= 5V 3.1 4.2 mA
Shutdown Supply Current
⎯
S
⎯
H
⎯
D
⎯
N = 0V, V
IN
≤ 60V, SW = 0V, V
C
Open
●
30 100
200
µA
µA
Lockout Threshold V
C
Open
●
2.3 2.42 2.53 V
Shutdown Threshold V
C
Open, Shutting Down
V
C
Open, Starting Up
●
●
0.15
0.25
0.37
0.42
0.58
0.60
V
V
Minimum SYNC Amplitude 1.5 V
SYNC Frequency Range (LT3430) 228 700 kHz
SYNC Frequency Range (LT3430-1) 125 250 kHz
SYNC Input Resistance 20 kΩ
Note 7: Switch on resistance is calculated by dividing V
IN
to SW voltage
by the forced current (3A). See Typical Performance Characteristics for the
graph of switch voltage at other currents.
Note 8: The LT3430EFE/LT3430EFE-1 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 LT3430IFE/LT3430IFE-1 are guaranteed over the full –40°C to 125°C
operating junction temperature range.
Note 9: See Peak Switch Current Limit vs Junction Temperature graph in
the Typical Performance Characteristics section.
Note 10: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specifi ed maximum operating junction
temperature may impair device reliability.
Note 11: The maximum operational Boost-SW voltage is limited by
thermal and load current constraints. See ‘Boost Pin’ and ‘Thermal
Calculations’ in the Applications Information section.
