Datasheet LT3688 (Analog Devices) - 4

LT3688
Th ELECTRICAL CHARACTERISTICS e
l
denotes the specifi cations which apply over the full operating junction temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V, unless otherwise noted. (Note 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
RST Pull-Up Current (Note 6) –1.5 –2.5 μA WDO Pull-Up Current (Note 6) –1.5 –2.5 μA CONFIG Low Level Input Voltage l 0.2 V CONFIG High Level Input Voltage l 1.4 V CONFIG Pin Voltage When Open 0.64 V Maximum CONFIG Input Current in Open l ±1 μA State CONFIG Pin Bias Current VCONFIG = 0V, VIN l ±20 μA
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The LT3688 contains circuitry that extends the maximum duty may cause permanent damage to the device. Exposure to any Absolute cycle if the BST voltage is 2V greater than the SW voltage. See the Maximum Rating condition for extended periods may affect device Applications Information section for more details. reliability and lifetime.
Note 5:
Current limit is guaranteed by design and/or correlation to static
Note 2:
Absolute Maximum Voltage at the VIN, CONFIG and EN/UVLO pins test. Slope compensation reduces current limit at higher duty cycles. is 36V for continuous operation.
Note 6:
The outputs of RST and WDO have a weak pull-up to VBIAS of
Note 3:
The LT3688 is tested under pulsed load conditions such that typically 2.5μA. However, external pull-up resistors may be used when TJ = TA. The LT3688E is guaranteed to meet performance specifi cations faster rise times are required or for VOH higher than VBIAS. from 0°C to 125°C junction temperature. Specifi cations over the –40°C
Note 7:
This IC includes overtemperature protection that is intended to 125°C operating junction temperature range are assured by design, to protect the device during momentary overload conditions. Junction characterization and correlation with statistical process controls. The temperature will exceed the maximum operating junction temperature LT3688I is guaranteed over the full –40°C to 125°C operating junction when over-temperature protection is active. Continuous operation above temperature range. The LT3688H is guaranteed over the full –40°C to the specifi ed maximum operating junction temperature may impair device 150°C operating junction temperature range. High junction temperatures reliability. degrade operating lifetimes. Operating lifetime is derated at junction
Note 8:
All currents into pins are positive; all voltages are referenced to temperatures greater than 125°C. The junction temperature (TJ, in °C) is GND unless otherwise specifi ed. calculated from the ambient temperature (TA, in °C) and power dissipation (PD, in Watts) according to the formula: TJ = TA + (PD θJA), where θJA (in °C/W) is the package thermal impedance.
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. Effi ciency, VOUT = 5V Effi ciency, VOUT = 3.3V Effi ciency, VOUT = 1.8V
95 90 85 fSW = 1MHz fSW = 1MHz fSW = 500kHz VIN = 12V VIN = 12V VIN = 12V 90 85 80 85 80 75 80 75 70 EFFICIENCY (%) 75 EFFICIENCY (%) 70 EFFICIENCY (%) 65 70 65 60 65 60 55 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A) 3688 G01 3688 G02 3688 G03 3688f 4