LT1959 Ver la hoja de datos (PDF) - Linear Technology

Número de pieza

componentes Descripción

Fabricante

LT1959

4.5A, 500kHz Step-Down Switching Regulator

Linear Technology 

LT1959

ELECTRICAL CHARACTERISTICS The q denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C, TJ = 25°C, VIN = 5V, VC = 1.5V, Boost = VIN + 5V, switch open, unless

otherwise noted.

PARAMETER

Switch On Resistance (Note 7)

Maximum Switch Duty Cycle

Switch Frequency

Switch Frequency Line Regulation

Frequency Shifting Threshold on FB Pin

Minimum Input Voltage (Note 3)

Minimum Boost Voltage (Note 4)

Boost Current (Note 5)

Input Supply Current (Note 6)

Shutdown Supply Current

Lockout Threshold

Shutdown Thresholds

Synchronization Threshold

Synchronizing Range

SYNC Pin Input Resistance

CONDITIONS

ISW = 4.5A

VFB = 1.05V

VC Set to Give 50% Duty Cycle

4.3V ≤ VIN ≤ 15V

∆f = 10kHz

ISW ≤ 4.5A

ISW = 1A

ISW = 4.5A

VSHDN = 0V, VSW = 0V, VC Open

VC Open

VC Open Device Shutting Down

Device Starting Up

MIN TYP MAX

0.07 0.1

q

0.13

90 93

q 86 93

460 500 540

q 440

560

q

0 0.15

q 0.5 0.7 1.0

q

4.0 4.3

q

2.3 3.0

q

20 35

q

90 140

q

3.8 5.4

15 50

q

75

q 2.3 2.38 2.46

q 0.13 0.37 0.60

q 0.25 0.45 0.7

q

1.5 2.2

580

1000

40

UNITS

Ω

Ω

%

%

kHz

kHz

%/ V

V

V

V

mA

mA

mA

µA

µA

V

V

V

V

kHz

kΩ

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

of a device may be impaired.

Note 2: Gain is measured with a VC swing equal to 200mV above the

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.

Note 7: Switch on resistance is calculated by dividing VIN to VSW voltage

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

the graph of switch voltage at other currents.

3

Share Link: