Datasheet LT1959 (Analog Devices) - 3

LT1959
ELECTRICAL CHARACTERISTICS The
●
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 CONDITIONS MIN TYP MAX UNITS
Switch On Resistance (Note 7) ISW = 4.5A 0.07 0.1 Ω ● 0.13 Ω Maximum Switch Duty Cycle VFB = 1.05V 90 93 % ● 86 93 % Switch Frequency VC Set to Give 50% Duty Cycle 460 500 540 kHz ● 440 560 kHz Switch Frequency Line Regulation 4.3V ≤ VIN ≤ 15V ● 0 0.15 %/ V Frequency Shifting Threshold on FB Pin ∆f = 10kHz ● 0.5 0.7 1.0 V Minimum Input Voltage (Note 3) ● 4.0 4.3 V Minimum Boost Voltage (Note 4) ISW ≤ 4.5A ● 2.3 3.0 V Boost Current (Note 5) ISW = 1A ● 20 35 mA ISW = 4.5A ● 90 140 mA Input Supply Current (Note 6) ● 3.8 5.4 mA Shutdown Supply Current VSHDN = 0V, VSW = 0V, VC Open 15 50 µA ● 75 µA Lockout Threshold VC Open ● 2.3 2.38 2.46 V Shutdown Thresholds VC Open Device Shutting Down ● 0.13 0.37 0.60 V Device Starting Up ● 0.25 0.45 0.7 V Synchronization Threshold ● 1.5 2.2 V Synchronizing Range 580 1000 kHz SYNC Pin Input Resistance 40 kΩ
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 4:
This is the minimum voltage across the boost capacitor needed to of a device may be impaired. guarantee full saturation of the internal power switch.
Note 2:
Gain is measured with a VC swing equal to 200mV above the
Note 5:
Boost current is the current flowing into the boost pin with the pin switching threshold level to 200mV below the upper clamp level. held 5V above input voltage. It flows only during switch on time.
Note 3:
Minimum input voltage is not measured directly, but is guaranteed
Note 6:
Input supply current is the bias current drawn by the input pin by other tests. It is defined as the voltage where internal bias lines are still with switching disabled. regulated so that the reference voltage and oscillator frequency remain
Note 7:
Switch on resistance is calculated by dividing VIN to VSW voltage constant. Actual minimum input voltage to maintain a regulated output will by the forced current (4.5A). See Typical Performance Characteristics for depend on output voltage and load current. See Applications Information. the graph of switch voltage at other currents. 3