3

LT1766/LT1766-5

1766fa

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Switch Current Limit

q

1.5

2

3

A

Switch On Resistance

0.2

0.3

Ω

q

0.4

Ω

Maximum Switch Duty Cycle

93

96

%

q

90

%

Switch Frequency

184

200

216

kHz

q

172

200

228

kHz

5.5V

q

0.05

0.15

%/V

Df = 10kHz

0.8

V

Minimum Input Voltage

(Note 3)

q

4.6

5.5

V

Minimum Boost Voltage

q

1.8

3

V

Boost Current (Note 5)

q

12

25

mA

q

45

70

mA

1.4

2.2

mA

2.9

4.2

mA

Shutdown Supply Current

25

75

µA

q

200

µA

Lockout Threshold

q

2.3

2.42

2.53

V

Shutdown Thresholds

q

0.15

0.37

0.6

V

q

0.25

0.45

0.6

V

Minimum SYNC Amplitude

q

1.5

2.2

V

SYNC Frequency Range

228

700

kHz

SYNC Input Resistance

20

k

Ω

ELECTRICAL CHARACTERISTICS

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

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 defined 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 flowing into the BOOST pin with the

pin held 5V above input voltage. It flows 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

the forced current (1.5A). 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 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 LT1766IGN,

LT1766IGN-5, LT1766IFE and LT1766IFE-5 are guaranteed over the full

–40

°C to 125°C operating junction temperature range.

Note 9: Transconductance and voltage gain refer to the internal amplifier

exclusive of the voltage divider. To calculate gain and transconductance,

refer to the SENSE pin on fixed voltage parts. Divide the values shown by

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 specified maximum operating junction

temperature may impair device reliability.