3

LT1506

ELECTRICAL CHARACTERISTICS

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Switch On Resistance (Note 7)

0.07

0.1

Ω

q

0.13

Ω

Maximum Switch Duty Cycle

90

93

%

q

86

93

%

Switch Frequency

460

500

540

kHz

q

440

560

kHz

Switch Frequency Line Regulation

4.3V

q

0

0.15

%/ V

Frequency Shifting Threshold on FB Pin

∆f = 10kHz

q

0.8

1.0

1.3

V

Minimum Input Voltage (Note 3)

q

4.0

4.3

V

Minimum Boost Voltage (Note 4)

q

2.3

3.0

V

Boost Current (Note 5)

q

20

35

mA

q

90

140

mA

Input Supply Current (Note 6)

q

3.8

5.4

mA

Shutdown Supply Current

15

50

µA

q

75

µA

Lockout Threshold

q

2.3

2.38

2.46

V

Shutdown Thresholds

q

0.13

0.37

0.60

V

Device Starting Up

q

0.25

0.45

0.7

V

Synchronization Threshold

q

1.5

2.2

V

Synchronizing Range

580

1000

kHz

SYNC Pin Input Resistance

40

k

Ω

temperature range.

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

of a device may be impaired.

switching threshold 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 frequency remain

constant. Actual minimum input voltage to maintain a regulated output will

depend on 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 bias current drawn by the input pin

with switching disabled.

by the forced current (4.5A). See Typical Performance Characteristics for

the graph of switch voltage at other currents.

Note 8: Transconductance and voltage gain refer to the internal amplifier

exclusive of the voltage divider. To calculate gain and transconductance

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