Datasheet LTC3855 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Dual, Multiphase Synchronous DC/DC Controller with Differential Remote Sense |
| Pages / Page | 44 / 4 — The. denotes the specifications which apply over the full operating |
| File Format / Size | PDF / 2.2 Mb |
| Document Language | English |
The. denotes the specifications which apply over the full operating
Model Line for this Datasheet
Text Version of Document
LTC3855 e
lecTrical characTerisTics
The
l
denotes the specifications which apply over the full operating junction temperature range (E-Grade), otherwise specifications are at TA = 25°C. VIN = 15V, VRUN1,2 = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
TG/BG t1D Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver 30 ns Synchronous Switch-On Delay Time BG/TG t2D 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) 90 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 38V 4.8 5 5.2 V VLDO INT INTVCC Load Regulation ICC = 0mA to 20mA 0.5 2 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive l 4.5 4.7 V VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5V 50 100 mV VLDOHYS EXTVCC Hysteresis 200 mV
Oscillator and Phase-Locked Loop
fNOM Nominal Frequency VFREQ = 1.2V 450 500 550 kHz fLOW Lowest Frequency VFREQ = 0V 210 250 290 kHz fHIGH Highest Frequency VFREQ ≥ 2.4V 700 770 850 kHz RMODE/PLLIN MODE/PLLIN Input Resistance 250 kΩ IFREQ Frequency Setting Current 9 10 11 µA CLKOUT Phase (Relative to Controller 1) PHASMD = GND 60 Deg PHASMD = Float 90 Deg PHASMD = INTVCC 120 Deg CLKHIGH Clock High Output Voltage 4 5 V CLKLOW Clock Low Output Voltage 0 0.2 V
PGOOD Output
VPGL PGOOD Voltage Low IPGOOD = 2mA 0.1 0.3 V IPGOOD PGOOD Leakage Current VPGOOD = 5V ±2 µA VPG PGOOD Trip Level, Either Controller VFB with Respect to Set Output Voltage VFB Ramping Negative –10 % VFB Ramping Positive 10 %
Differential Amplifier
ADA Gain l 0.998 1 1.002 V/V RIN Input Resistance Measured at DIFFP Input 80 kΩ VOS Input Offset Voltage VDIFFP = VDIFFOUT = 1.5V, IDIFFOUT = 100µA 2 mV PSRROA Power Supply Rejection Ratio 5V < VIN < 38V 100 dB ICL Maximum Output Current 2 3 mA VOUT(MAX) Maximum Output Voltage IDIFFOUT = 300µA VINTVCC – 1.4 VINTVCC – 1.1 V GBW Gain Bandwidth Product (Note 8) 3 MHz Slew Rate Differential Amplifier Slew Rate (Note 8) 2 V/µs 3855f Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Package Description Related Parts
lecTrical characTerisTics
The
l
denotes the specifications which apply over the full operating junction temperature range (E-Grade), otherwise specifications are at TA = 25°C. VIN = 15V, VRUN1,2 = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
TG/BG t1D Top Gate Off to Bottom Gate On Delay CLOAD = 3300pF Each Driver 30 ns Synchronous Switch-On Delay Time BG/TG t2D 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) 90 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 38V 4.8 5 5.2 V VLDO INT INTVCC Load Regulation ICC = 0mA to 20mA 0.5 2 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive l 4.5 4.7 V VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5V 50 100 mV VLDOHYS EXTVCC Hysteresis 200 mV
Oscillator and Phase-Locked Loop
fNOM Nominal Frequency VFREQ = 1.2V 450 500 550 kHz fLOW Lowest Frequency VFREQ = 0V 210 250 290 kHz fHIGH Highest Frequency VFREQ ≥ 2.4V 700 770 850 kHz RMODE/PLLIN MODE/PLLIN Input Resistance 250 kΩ IFREQ Frequency Setting Current 9 10 11 µA CLKOUT Phase (Relative to Controller 1) PHASMD = GND 60 Deg PHASMD = Float 90 Deg PHASMD = INTVCC 120 Deg CLKHIGH Clock High Output Voltage 4 5 V CLKLOW Clock Low Output Voltage 0 0.2 V
PGOOD Output
VPGL PGOOD Voltage Low IPGOOD = 2mA 0.1 0.3 V IPGOOD PGOOD Leakage Current VPGOOD = 5V ±2 µA VPG PGOOD Trip Level, Either Controller VFB with Respect to Set Output Voltage VFB Ramping Negative –10 % VFB Ramping Positive 10 %
Differential Amplifier
ADA Gain l 0.998 1 1.002 V/V RIN Input Resistance Measured at DIFFP Input 80 kΩ VOS Input Offset Voltage VDIFFP = VDIFFOUT = 1.5V, IDIFFOUT = 100µA 2 mV PSRROA Power Supply Rejection Ratio 5V < VIN < 38V 100 dB ICL Maximum Output Current 2 3 mA VOUT(MAX) Maximum Output Voltage IDIFFOUT = 300µA VINTVCC – 1.4 VINTVCC – 1.1 V GBW Gain Bandwidth Product (Note 8) 3 MHz Slew Rate Differential Amplifier Slew Rate (Note 8) 2 V/µs 3855f Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Package Description Related Parts
