Datasheet LTC1875 (Analog Devices) - 3

LTC1875
ELECTRICAL CHARACTERISTICS The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25
°
C. VIN = 3.6V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VRUN RUN Threshold VRUN Ramping Up ● 0.2 0.7 1.5 V IRUN RUN Input Current VRUN = 0V ±0.01 ±1 µA
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 4:
The LTC1875 is tested in a feedback loop which servos VFB to the of a device may be impaired. balance point for the error amplifier (VITH = 1.2V)
Note 2:
The LTC1875E is guaranteed to meet specified performance from
Note 5:
Dynamic supply current is higher due to the gate charge being 0°C to 70°C. Specifications over the – 40°C to 85°C operating temperature delivered at the switching frequency. range are assured by design, characterization and correlation with
Note 6:
This IC includes overtemperature protection that is intended to statistical process controls. protect the device during momentary overload conditions. Junction
Note 3:
TJ is calculated from the ambient temperature TA and power temperature will exceed 125°C when overtemperature protection is active. dissipation PD according to the following formula: Continuous operation above the specified maximum operating junction LTC1875: T temperature may impair device reliability. J = TA + (PD • 110°C/W)
W U TYPICAL PERFOR A CE CHARACTERISTICS Oscillator Frequency Oscillator Frequency RDS(ON) vs Temperature vs Temperature vs Supply Voltage
0.8 595 580 SYNCHRONOUS SWITCH VIN = 3.6V 0.7 MAIN SWITCH VIN = 3V 575 570 0.6 ) Ω 0.5 VIN = 5V 555 560 ( 0.4 DS(ON)R 0.3 535 550 FREQUENCY (kHz) 0.2 V V IN = 3V IN = 5V OSC FREQUENCY (kHz) 515 540 0.1 0 495 530 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 0 2 4 6 8 TEMPERATURE (°C) TEMPERATURE (°C) SUPPLY VOLTAGE (V) 1875 G01 1875 G02 1875 G03
DC Supply Current Switch Leakage Current vs Temperature RDS(ON) vs Input Voltage vs Temperature
300 0.6 10 VIN = 3.6V VIN = 7V 9 RUN = 0V 250 0.5 8 PULSE SKIPPING MODE SYNCHRONOUS SWITCH µA) µA) 7 200 0.4 ) Ω 6 ( MAIN SWITCH 150 0.3 5 DS(ON)R 4 100 0.2 3 SUPPLY CURRENT ( MAIN SWITCH SWITCH LEAKAGE ( 2 50 0.1 SYNCHRONOUS SWITCH 1 BURST MODE 0 0 0 –50 0 50 100 125 0 2 4 6 8 –50 0 50 100 125 TEMPERATURE (°C) INPUT VOLTAGE (V) TEMPERATURE (°C) 1875 G04 1875 G05 1875 G06 1875f 3