Datasheet LTC3868 (Analog Devices) - 4

LTC3868
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
BG/TG t1D Bottom Gate Off to Top Gate On Delay CLOAD = 3300pF Each Driver 30 ns Top Switch-On Delay Time tON(MIN) Minimum On-Time (Note 7) 95 ns
INTVCC Linear Regulator
VINTVCCVIN Internal VCC Voltage 6V < VIN < 24V, VEXTVCC = 0V 4.85 5.1 5.35 V VLDOVIN INTVCC Load Regulation ICC = 0mA to 50mA, VEXTVCC = 0V 0.7 1.1 % VINTVCCEXT Internal VCC Voltage 6V < VEXTVCC < 13V 4.85 5.1 5.35 V VLDOEXT INTVCC Load Regulation ICC = 0mA to 50mA, VEXTVCC = 8.5V 0.6 1.1 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive 4.5 4.7 4.9 V VLDOHYS EXTVCC Hysteresis 250 mV
Oscillator and Phase-Locked Loop
f25kΩ Programmable Frequency RFREQ = 25k, PLLIN/MODE = DC Voltage 105 kHz f65kΩ Programmable Frequency RFREQ = 65k, PLLIN/MODE = DC Voltage 375 440 505 kHz f105kΩ Programmable Frequency RFREQ = 105k, PLLIN/MODE = DC Voltage 835 kHz fLOW Low Fixed Frequency VFREQ = 0V, PLLIN/MODE = DC Voltage 320 350 380 kHz fHIGH High Fixed Frequency VFREQ = INTVCC, PLLIN/MODE = DC Voltage 485 535 585 kHz fSYNC Synchronizable Frequency PLLIN/MODE = External Clock l 75 850 kHz
PGOOD1 and PGOOD2 Outputs
VPGL PGOOD Voltage Low IPGOOD = 2mA 0.2 0.4 V IPGOOD PGOOD Leakage Current VPGOOD = 5V ±1 µA VPG PGOOD Trip Level VFB with Respect to Set Regulated Voltage VFB Ramping Negative –13 –10 –7 % Hysteresis 2.5 % VFB with Respect to Set Regulated Voltage VFB Ramping Positive 7 10 13 % Hysteresis 2.5 % tPG Delay for Reporting a Fault (PGOOD Low) 25 µs
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The LTC3868 is tested in a feedback loop that servos VITH1,2 to a may cause permanent damage to the device. Exposure to any Absolute specified voltage and measures the resultant VFB1,2. Maximum Ratings for extended periods may affect device reliability and
Note 5:
Dynamic supply current is higher due to the gate charge being lifetime. delivered at the switching frequency. See Applications information.
Note 2:
The LTC3868E is guaranteed to meet performance specifications
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay from 0°C to 85°C. Specifications over the –40°C to 85°C operating times are measured using 50% levels. temperature range are assured by design, characterization and correlation
Note 7:
The minimum on-time condition is specified for an inductor with statistical process controls. The LTC3868I is guaranteed over the full peak-to-peak ripple current ≥ 40% of I –40°C to 85°C operating temperature range. MAX (See Minimum On-Time Considerations in the Applications Information section).
Note 3:
TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: TJ = TA + (PD • 34°C/W) 3868fe 4 For more information www.linear.com/LTC3868 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Typical Performance Characteristics Pin Functions Operation Package Description Typical Application Related Parts