Datasheet LTC3858-2 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Low IQ, Dual 2-Phase Synchronous Step-Down Controller |
| Pages / Page | 40 / 4 — ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply … |
| File Format / Size | PDF / 448 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply over the full operating
Model Line for this Datasheet
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LTC3858-2
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 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 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 25 μs Low)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
TJ is calculated from the ambient temperature TA and power may cause permanent damage to the device. Exposure to any Absolute dissipation PD according to the following formula: Maximum Ratings for extended periods may affect device reliability and TJ = TA + (PD • 34°C/W) lifetime.
Note 4:
The LTC3858-2 is tested in a feedback loop that servos VITH1,2 to
Note 2:
The LTC3858-2 is tested under pulsed load conditions such that a specified voltage and measures the resultant VFB1,2. The specification at TJ ≈ TA. The LTC3858E-2 is guaranteed to meet performance specifications 85°C is not tested in production. This specification is assured by design, from 0°C to 85°C. Specifications over the –40°C to 125°C operating characterization and correlation to production testing at 125°C. junction temperature range are assured by design, characterization and
Note 5:
Dynamic supply current is higher due to the gate charge being correlation with statistical process controls. The LTC3858I-2 is guaranteed delivered at the switching frequency. See the Applications information over the full –40°C to 125°C operating junction temperature range. section. Note that the maximum ambient temperature is determined by specific
Note 6:
Rise and fall times are measured using 10% and 90% levels. operating conditions in conjunction with board layout, the rated package Delay times are measured using 50% levels thermal resistance and other environmental factors.
Note 7:
The minimum on-time condition is specified for an inductor peak-to-peak ripple current ≥ of 40% IMAX (See Minimum On-Time Considerations in the Applications Information section). 38582f 4
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 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 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 25 μs Low)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
TJ is calculated from the ambient temperature TA and power may cause permanent damage to the device. Exposure to any Absolute dissipation PD according to the following formula: Maximum Ratings for extended periods may affect device reliability and TJ = TA + (PD • 34°C/W) lifetime.
Note 4:
The LTC3858-2 is tested in a feedback loop that servos VITH1,2 to
Note 2:
The LTC3858-2 is tested under pulsed load conditions such that a specified voltage and measures the resultant VFB1,2. The specification at TJ ≈ TA. The LTC3858E-2 is guaranteed to meet performance specifications 85°C is not tested in production. This specification is assured by design, from 0°C to 85°C. Specifications over the –40°C to 125°C operating characterization and correlation to production testing at 125°C. junction temperature range are assured by design, characterization and
Note 5:
Dynamic supply current is higher due to the gate charge being correlation with statistical process controls. The LTC3858I-2 is guaranteed delivered at the switching frequency. See the Applications information over the full –40°C to 125°C operating junction temperature range. section. Note that the maximum ambient temperature is determined by specific
Note 6:
Rise and fall times are measured using 10% and 90% levels. operating conditions in conjunction with board layout, the rated package Delay times are measured using 50% levels thermal resistance and other environmental factors.
Note 7:
The minimum on-time condition is specified for an inductor peak-to-peak ripple current ≥ of 40% IMAX (See Minimum On-Time Considerations in the Applications Information section). 38582f 4
