Datasheet LTC3858-1 (Analog Devices) - 4

LTC3858-1
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating junction temperature range, otherwise specifi cations are at TA = 25°C (Note 2). VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
BG Transistion Time: (Note 6) BG1,2 tr Rise Time CLOAD = 3300pF 28 ns BG1,2 tf Fall Time CLOAD = 3300pF 13 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver 30 ns Synchronous Switch-On Delay Time 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 < 38V, 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 Voltage 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 Output
VPGL PGOOD1 Voltage Low IPGOOD = 2mA 0.2 0.4 V IPGOOD PGOOD1 Leakage Current VPGOOD = 5V ±1 μA VPG PGOOD1 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 where θJA = 43°C/W for the QFN package and θJA = 90°C/W for the SSOP may cause permanent damage to the device. Exposure to any Absolute package. Maximum Ratings for extended periods may affect device reliability and
Note 4:
The LTC3858-1 is tested in a feedback loop that servos V lifetime. ITH1,2 to a specifi ed voltage and measures the resultant VFB1,2. The specifi cation at
Note 2:
The LTC3858-1 is tested under pulsed conditions such that 85°C is not tested in production. This specifi cation is assured by design, TJ ≈ TA. The LTC3858E-1 is guaranteed to meet performance specifi cations characterization and correlation to production testing at 125°C. from 0°C to 85°C. Specifi cations over the –40°C to 125°C operating
Note 5:
Dynamic supply current is higher due to the gate charge being junction temperature range are assured by design, characterization and delivered at the switching frequency. See Applications information. correlation with statistical process controls. The LTC3858I-1 is guaranteed
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay over the full –40°C to 125°C operating junction temperature range. times are measured using 50% levels Note that the maximum ambient temperature is determined by specifi c operating conditions in conjunction with board layout, the rated package
Note 7:
The minimum on-time condition is specifi ed for an inductor peak- thermal resistance and other environmental factors. to-peak ripple current ≥ of IMAX (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 • θJA) 38581fd 4