Datasheet LTC3870-1 (Analog Devices) - 3

LTC3870-1
elecTrical 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
VIILIMIT Maximum Current Sense Threshold (High Range) VITH = 2.22V, ILIM = INTVCC l 70 75 80 mV Maximum Current Sense Threshold (Low Range) VITH = 2.22V, ILIM = GND l 45 50 55 mV
PWM Outputs
PWM PWM Output High Voltage ILOAD = 500µA l VCC – 0.2 V PWM Output Low Voltage ILOAD = –500µA l 0.2 V PWM Output Current in Hi-Z State –5 5 µA tON(MIN) Minimum On-Time (Note 5) 90 ns
INTVCC Regulator
VINTVCC_VIN Internal VCC Voltage No Load 6.0V < VIN < 60V, VEXTVCC = 0V 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 6) 4.85 5.1 5.35 V VLDO EXT EXTVCC Load Regulation ICC = 0mA to 20mA, VEXTVCC = 8.5V 0.5 ±2 % VEXTVCC EXTVCC Switchover Voltage VEXTVCC Ramping Positive (Note 6) 4.65 4.8 4.95 V VHYS_EXTVCC EXTVCC Hysteresis 200 mV
Oscillator and Phase-Locked Loop
fSYNC Oscillator SYNC Range l 100 1000 kHz VTH,SYNC SYNC Input Threshold VTH,SYNC Falling (Note 7) 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 θSYNC-θ0 SYNC to Ch0 Phase Relationship Based on the PHASMD =0 180 Deg Falling Edge of SYNC and Rising Edge of PWM0 PHASMD = 1/3 INTVCC 60 Deg PHASMD = 2/3 INTVCC 120 Deg PHASMD = INTVCC 90 Deg θSYNC-θ1 SYNC to Ch1 Phase Relationship Based on the PHASMD = 0 0 Deg Falling Edge of SYNC and Rising Edge of PWM1 PHASMD = 1/3 INTVCC 300 Deg PHASMD = 2/3 INTVCC 240 Deg PHASMD = INTVCC 270 Deg
Digital Inputs RUN0/RUN1, MODE0/MODE1, FAULT0/FAULT1
VIH Input High Threshold Voltage l 2.0 V VIL Input Low Threshold Voltage l 1.4 V
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings impedance and other environmental factors. The junction temperature TJ may cause permanent damage to the device. Exposure to any Absolute is calculated from the ambient temperature TA and power dissipation PD Maximum Rating condition for extended periods may affect device according to the following formula: reliability and lifetime. TJ = TA + (PD • 46.9°C/W)
Note 2:
The LTC3870-1 is tested under pulsed load conditions such that
Note 3:
When VIN >15V, EXTVCC is recommended to reduce IC Temperature. TJ ≈ TA. The LTC3870E-1 is guaranteed to meet specifications from
Note 4:
Output voltage is set and controlled by the master controller in 0°C to 85°C junction temperature. Specifications over the –40°C to multiphase operations. 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The
Note 5:
The minimum on-time condition corresponds to an inductor LTC3870I-1 is guaranteed over the full –40°C to 125°C operating peak-to-peak ripple current ≥40% of IMAX (see Minimum On-Time junction temperature range. Note that the maximum ambient temperature Considerations in the Applications Information section). consistent with these specifications is determined by specific operating
Note 6:
EXTVCC is enabled only if VIN is higher than 6.5V. conditions in conjunction with board layout, the related package thermal
Note 7:
Guaranteed by design. 38701f For more information www.linear.com/LTC3870-1 3 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts