Datasheet LTC7878 (Analog Devices) - 4

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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 > 1.25V unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS DRV
CC
and INTV
CC
Linear Regulators
VDRVCC DRVCC Regulation Voltage VIN = 12V, EXTVCC = 0V 6.8 7 7.2 V VIN = 5V, EXTVCC = 12V 6.8 7 7.2 V VDRVCC_LREG DRVCC Voltage Load Regulation IDRVCC = 0mA to 55mA, VIN = 12V 1 2 % VINTVCC INTVCC Regulation Voltage 4.8 5 5.2 V
Oscillator and Phase Locked Loop
IFREQ FREQ Pin Output Current 9 10 11 µA fSW(MIN) Low Fixed Switching Frequency VFREQ = 0V 50 kHz fSW(MAX) High Fixed Switching Frequency VFREQ = 5V 800 kHz fSW_SYNC Synchronizable Frequency SYNC = External Clock 100 600 kHz VTH_SYNC SYNC Pin Input Threshold SYNC Pin Rising 1.2 2 V SYNC Pin Falling 0.5 0.9 V RSYNC SYNC Pin Input Resistance to Ground 500 kΩ Clock Output High Voltage 4.8 5 V Clock Output Low Voltage 0 0.2 V
Power Good
VPGOOD PGOOD Trip Level, VFB Respect to Set VFB Ramping Negative –10 % Regulated Voltage VFB Ramping Positive 10 % RPGOOD PGOOD Open Drain On-Resistance 55 Ω IPGOOD PGOOD Leakage Current VPGOOD = 6V ±1 µA
Gate Drivers
RTG1, RTG2 Top Driver Pull-Up On-Resistance BOOST – SW = 7V 3 Ω Top Driver Pull-Down On-Resistance BOOST – SW = 7V 1.5 Ω RBG1, RBG2 Bottom Driver Pull-Up On-Resistance DRVCC = 7V 3.5 Ω Bottom Driver Pull-Down On-Resistance DRVCC = 7V 3 Ω
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings at –40°C and 125°C are not tested in production and are assured by may cause permanent damage to the device. Exposure to any Absolute design, characterization and correlation to production testing at other Maximum Rating condition for extended periods may affect device temperatures. reliability and lifetime.
Note 5:
Dynamic supply current is higher due to the gate charge being
Note 2:
The LTC7878 is tested under pulsed load conditions such that TJ delivered at the switching frequency. See Applications Information section. ≈ TA. The LTC7878A is guaranteed to meet specifications from –40°C to
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay 125°C junction temperature. High junction temperatures degrade operating times are measured using 50% levels. lifetimes; operating lifetime is derated for junction temperatures greater
Note 7:
The minimum on-time condition is specified for an inductor than 125°C. Note that the maximum ambient temperature consistent peak-to-peak ripple current > 40% of I with these specifications is determined by specific operating conditions L(MAX) (See Minimum On-Time Considerations in the Applications Information section). in conjunction with board layout, the rated package thermal impedance and other environmental factors. The junction temperature (T
Note 8:
This IC includes overtemperature protection that is intended to J, in °C) is calculated from the ambient temperature (T protect the device during momentary overload conditions. The maximum A, in °C) and power dissipation (P rated junction temperature will be exceeded when this protection is active. D, in Watts) according to the formula: TJ = TA + (PD • JA), where θJA (in °C/W) is the package thermal impedance. Continuous operation above the specified absolute maximum operating junction temperature may impair device reliability or permanently damage
Note 3:
When VIN > EXTVCC and EXTVCC > 8V, VBIAS supply current is the device. transferred to EXTVCC pin to reduce the total input supply quiescent current.
Note 9:
Do not apply a voltage or current source to these pins. They must be connected to capacitive loads only, otherwise permanent damage may occur.
Note 4:
The LTC7878 is tested in a feedback loop that servos VITH to a specified voltage and measures the resultant V
Note 10:
Guaranteed by design. FB. The specifications Rev. C 4 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts