Datasheet LTC3868-1 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Low IQ, Dual 2-Phase Synchronous Step-Down Controller |
| Pages / Page | 38 / 4 — ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply … |
| File Format / Size | PDF / 475 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply over the full operating
Model Line for this Datasheet
Text Version of Document
LTC3868-1
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
BG Transition 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 < 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 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 for the QFN package and θJA = 90°C 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 LTC3868-1 is tested in a feedback loop that servos V lifetime. ITH1,2 to a specifi ed voltage and measures the resultant VFB1,2.
Note 2:
The LTC3868E-1 is guaranteed to meet performance specifi cations
Note 5:
Dynamic supply current is higher due to the gate charge being from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating delivered at the switching frequency. See Applications information. temperature range are assured by design, characterization and correlation
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay with statistical process controls. The LTC3868I-1 is guaranteed over the times are measured using 50% levels. full –40°C to 85°C operating temperature range.
Note 7:
The minimum on-time condition is specifi ed for an inductor
Note 3:
TJ is calculated from the ambient temperature TA and power peak-to-peak ripple current ≥ 40% of I dissipation P MAX (See Minimum On-Time D according to the following formula: Considerations in the Applications Information section). TJ = TA + (PD • θJA) 38681fd 4
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
BG Transition 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 < 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 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 for the QFN package and θJA = 90°C 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 LTC3868-1 is tested in a feedback loop that servos V lifetime. ITH1,2 to a specifi ed voltage and measures the resultant VFB1,2.
Note 2:
The LTC3868E-1 is guaranteed to meet performance specifi cations
Note 5:
Dynamic supply current is higher due to the gate charge being from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating delivered at the switching frequency. See Applications information. temperature range are assured by design, characterization and correlation
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay with statistical process controls. The LTC3868I-1 is guaranteed over the times are measured using 50% levels. full –40°C to 85°C operating temperature range.
Note 7:
The minimum on-time condition is specifi ed for an inductor
Note 3:
TJ is calculated from the ambient temperature TA and power peak-to-peak ripple current ≥ 40% of I dissipation P MAX (See Minimum On-Time D according to the following formula: Considerations in the Applications Information section). TJ = TA + (PD • θJA) 38681fd 4
