Datasheet LTC3870 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | PolyPhase Step-Down Slave Controller for Digital Power System Management |
| Pages / Page | 22 / 3 — e lecTrical characTerisTics The. denotes the specifications which apply … |
| File Format / Size | PDF / 928 Kb |
| Document Language | English |
e lecTrical characTerisTics The. denotes the specifications which apply over the specified operating
Model Line for this Datasheet
Text Version of Document
LTC3870
e lecTrical characTerisTics The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. (Note 2) VIN = 15V, VRUN0,VRUN1 = 3.3V, fSYNC = 350kHz (externally driven) unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Control Loop
I + + ISENSE0 , Current Sense + Pin Current VISENSE0,1 = 3.3V l ±0.1 ±1 µA I + ISENSE1 I – – ISENSE0 , Current Sense − Pin Current VISENSE0,1 = 3.3V l ±0.1 ±1 µA I – ISENSE1 VIILIMIT Maximum Current Sense threshold VITH = 2.22V, ILIM = INTVCC l 70 75 80 mV (High Range) Maximum Current Sense threshold VITH = 2.22V, ILIM = GND l 45 50 55 mV (Low Range)
Gate Drivers
TG RUP Pull-Up On-Resistance TG High 2.5 Ω TG RDOWN Pull-down On-Resistance TG Low 1.5 Ω BG RUP Pull-Up On-Resistance BG High 2.4 Ω BG RDOWN Pull-down On-Resistance BG Low 1.1 Ω TG0, TG1 TG Transition Time: (Note 6) tr Rise Time CLOAD = 3300pF 30 ns tf Fall Time CLOAD = 3300pF 30 ns BG0, BG1 BG Transition Time: (Note 6) tr Rise Time CLOAD = 3300pF 30 ns tf Fall Time CLOAD = 3300pF 30 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Time (Note 6) 30 ns CLOAD = 3300pF Each Driver BG/TG t2D Bottom Gate Off to Top Gate On Delay Time (Note 6) 30 ns CLOAD = 3300pF Each Driver tON(MIN) Minimum On-Time (Note 7) 90 ns
INTVCC Regulator
VINTVCC_VIN Internal VCC Voltage No Load 6.0V <VIN <60V, VEXTVCC = 0 V 4.85 5.1 5.35 V VLDO INT INTVCC Load Regulation ICC = 0mA to 50mA, VEXTVCC = 0V 0.8 ±2 % VINTVCC_EXT Internal VCC Voltage No Load VEXTVCC = 8.5V (Note 8) 4.85 5.1 5.35 V VLDO EXT INTVCC Load Regulation with EXTVCC ICC = 0 to 20mA, VEXTVCC = 8.5V 0.5 ±2 % VEXTVCC EXTVCC Switchover Voltage VEXTVCC Ramping Positive (Note 8) 4.7 4.8 4.9 V VHYS_EXTVCC EXTVCC HYSTERESIS 200 mV
Oscillator and Phase-Locked Loop
fSNYC Oscillator SYNC Range l 100 1000 kHz VTH,SYNC SYNC Input Threshold VTH,sync Falling (Note 9) 0.4 V VTH,sync Rising 2.0 V fNOM Nominal Frequency VFREQ = 1.0V 500 kHz IFREQ FREQ setting current 9 10 11 µA θ SYNC-θ0 SYNC to Ch0 Phase Relationship Based on PHASMD = 0 180 Deg the Falling Edge of Sync and Rising Edge of PHASMD = 1/3 INTVCC 60 Deg TG0 PHASMD = 2/3 INTVCC 120 Deg PHASMD = INTVCC 90 Deg θ SYNC-θ1 SYNC to Ch1 Phase Relationship Based on PHASMD = 0 0 Deg the Falling Edge of Sync and Rising Edge of PHASMD = 1/3 INTVCC 300 Deg TG1 PHASMD = 2/3 INTVCC 240 Deg PHASMD = INTVCC 270 Deg 3870fb For more information www.linear.com/LTC3870 3
e lecTrical characTerisTics The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. (Note 2) VIN = 15V, VRUN0,VRUN1 = 3.3V, fSYNC = 350kHz (externally driven) unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Control Loop
I + + ISENSE0 , Current Sense + Pin Current VISENSE0,1 = 3.3V l ±0.1 ±1 µA I + ISENSE1 I – – ISENSE0 , Current Sense − Pin Current VISENSE0,1 = 3.3V l ±0.1 ±1 µA I – ISENSE1 VIILIMIT Maximum Current Sense threshold VITH = 2.22V, ILIM = INTVCC l 70 75 80 mV (High Range) Maximum Current Sense threshold VITH = 2.22V, ILIM = GND l 45 50 55 mV (Low Range)
Gate Drivers
TG RUP Pull-Up On-Resistance TG High 2.5 Ω TG RDOWN Pull-down On-Resistance TG Low 1.5 Ω BG RUP Pull-Up On-Resistance BG High 2.4 Ω BG RDOWN Pull-down On-Resistance BG Low 1.1 Ω TG0, TG1 TG Transition Time: (Note 6) tr Rise Time CLOAD = 3300pF 30 ns tf Fall Time CLOAD = 3300pF 30 ns BG0, BG1 BG Transition Time: (Note 6) tr Rise Time CLOAD = 3300pF 30 ns tf Fall Time CLOAD = 3300pF 30 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Time (Note 6) 30 ns CLOAD = 3300pF Each Driver BG/TG t2D Bottom Gate Off to Top Gate On Delay Time (Note 6) 30 ns CLOAD = 3300pF Each Driver tON(MIN) Minimum On-Time (Note 7) 90 ns
INTVCC Regulator
VINTVCC_VIN Internal VCC Voltage No Load 6.0V <VIN <60V, VEXTVCC = 0 V 4.85 5.1 5.35 V VLDO INT INTVCC Load Regulation ICC = 0mA to 50mA, VEXTVCC = 0V 0.8 ±2 % VINTVCC_EXT Internal VCC Voltage No Load VEXTVCC = 8.5V (Note 8) 4.85 5.1 5.35 V VLDO EXT INTVCC Load Regulation with EXTVCC ICC = 0 to 20mA, VEXTVCC = 8.5V 0.5 ±2 % VEXTVCC EXTVCC Switchover Voltage VEXTVCC Ramping Positive (Note 8) 4.7 4.8 4.9 V VHYS_EXTVCC EXTVCC HYSTERESIS 200 mV
Oscillator and Phase-Locked Loop
fSNYC Oscillator SYNC Range l 100 1000 kHz VTH,SYNC SYNC Input Threshold VTH,sync Falling (Note 9) 0.4 V VTH,sync Rising 2.0 V fNOM Nominal Frequency VFREQ = 1.0V 500 kHz IFREQ FREQ setting current 9 10 11 µA θ SYNC-θ0 SYNC to Ch0 Phase Relationship Based on PHASMD = 0 180 Deg the Falling Edge of Sync and Rising Edge of PHASMD = 1/3 INTVCC 60 Deg TG0 PHASMD = 2/3 INTVCC 120 Deg PHASMD = INTVCC 90 Deg θ SYNC-θ1 SYNC to Ch1 Phase Relationship Based on PHASMD = 0 0 Deg the Falling Edge of Sync and Rising Edge of PHASMD = 1/3 INTVCC 300 Deg TG1 PHASMD = 2/3 INTVCC 240 Deg PHASMD = INTVCC 270 Deg 3870fb For more information www.linear.com/LTC3870 3
