Datasheet LTC7803 (Analog Devices) - 5

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ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, RUN = 12V, EXTVCC = 0V, unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Spread Spectrum Oscillator and Phase-Locked Loop
fOSC Low Fixed Frequency VFREQ = 0V, PLLIN/SPREAD = 0V 340 375 410 kHz High Fixed Frequency VFREQ = INTVCC, PLLIN/SPREAD = 0V l 2.0 2.25 2.5 MHz Programmable Frequency RFREQ = 374kΩ, PLLIN/SPREAD = 0V 100 kHz RFREQ =75kΩ, PLLIN/SPREAD = 0V 450 500 550 kHz RFREQ = 12.5kΩ, PLLIN/SPREAD = 0V 3 MHz fSYNC Synchronizable Frequency Range PLLIN/SPREAD = External Clock l 0.1 3 MHz PLLIN Input High Level l 2.2 V PLLIN Input Low Level l 0.5 V Spread Spectrum Frequency Range PLLIN/SPREAD = INTVCC (Relative to fOSC) Minimum Frequency 0 % Maximum Frequency 20 %
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The LTC7803 is tested in a feedback loop that servos VITH to a may cause permanent damage to the device. Exposure to any Absolute specified voltage and measures the resultant VFB. The specification at 85°C Maximum Rating condition for extended periods may affect device is not tested in production and is assured by design, characterization and reliability and lifetime. correlation to production testing at other temperatures (125°C for the
Note 2:
The LTC7803 is tested under pulsed load conditions such that LTC7803E/LTC7803I, 150°C for the LTC7803J/LTC7803H). TJ ≈ TA. The LTC7803E is guaranteed to meet specifications over a 0°C
Note 5:
Dynamic supply current is higher due to the gate charge being to 125°C operating junction temperature range. Specifications down to delivered at the switching frequency. See Applications Information. –40°C operating junction temperature for the LTC7803E is assured by
Note 6:
Rise and fall times are measured using 10% and 90% levels. design, characterization and correlation with statistical process controls. Delay times are measured using 50% levels. The LTC7803I is guaranteed over the –40°C to 125°C operating junction
Note 7:
The minimum on-time condition is specified for an inductor temperature range. The LTC7803J and LTC7803H are guaranteed over peak-to-peak ripple current >40% of I the –40°C to 150°C operating junction temperature range. High junction MAX (See Minimum On-Time Considerations in the Applications Information section). temperatures degrade operating lifetimes; operating lifetime is derated for junction temperatures greater than 125°C. Note that the maximum
Note 8:
This IC includes overtemperature protection that is intended to ambient temperature consistent with these specifications is determined by protect the device during momentary overload conditions. The maximum specific operating conditions in conjunction with board layout, the rated rated junction temperature will be exceeded when this protection is active. package thermal impedance and other environmental factors. The junction Continuous operation above the specified absolute maximum operating temperature (T junction temperature may impair device reliability or permanently damage J, in °C) is calculated from the ambient temperature (TA, in °C) and power dissipation (PD, in Watts) according to the formula: T the device. J = TA + (P
Note 9:
Do not apply a voltage or current source to these pins. They must D • θJA), where θJA (in °C/W) is the package thermal impedance.
Note 3:
When SENSE– ≥ 3.2V or EXTV be connected to capacitive loads only, otherwise permanent damage may CC ≥ 4.8V, VIN supply current is transferred to these pins to reduce the total input supply quiescent current. occur. SENSE– bias current is reflected to the input supply by the formula IVIN = ISENSE– • VOUT/(VIN • h), where h is the efficiency. EXTVCC bias current is similarly reflected to the input supply when biased by an output greater than the EXTVCC LDO Switchover Voltage (4.7V typical). Rev 0 For more information www.analog.com 5 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Package Description Typical Application Related Parts