Datasheet LTC3877 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | Dual Phase Step-Down Synchronous Controller with VID Output Voltage Programming and Low Value DCR Sensing |
| Pages / Page | 46 / 5 — e lecTrical characTerisTics The. denotes the specifications which apply … |
| File Format / Size | PDF / 1.1 Mb |
| Document Language | English |
e lecTrical characTerisTics The. denotes the specifications which apply over the full operating
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LTC3877
e lecTrical characTerisTics The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 3). VIN = 15V, VRUN = 5V unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS INTVCC Linear Regulator
VINTVCC Internal LDO Output Voltage 6V < VIN < 38V 5.3 5.5 5.7 V VLDO INT INTVCC Load Regulation ICC = 0 to 20mA 0.5 2.0 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Rising l 4.5 4.7 V VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5.5V 40 100 mV VLDOHYS EXTVCC Hysteresis 300 mV
Oscillator and Phase-Locked Loop
fNOM Nominal Frequency VFREQ = 1.22V 575 625 675 kHz fRANGE PLL SYNC Range l 250 1000 kHz VSYNC MODE/PLLIN Sync Input Threshold VSYNC Rising 1.6 V VSYNC Falling 1 V RMODE/PLLIN MODE/PLLIN Input Resistance 250 kΩ IFREQ Frequency Setting Current VFREQ = 1.2V 9 10 11 μA VCLKOUT High Output Voltage VINTVCC = 5.5V 4 5.5 V Low Output Voltage 0 0.2 V Φ2 – Φ1 Channel 2 to Channel 1 Phase Delay VPHSMD = 0V 180 Deg VPHSMD = Float 180 Deg VPHSMD = INTVCC 240 Deg ΦCLKOUT – Φ1 CLKOUT to Channel 1 Phase Delay VPHSMD = 0V 60 Deg VPHSMD = Float 90 Deg VPHSMD = INTVCC 120 Deg
Power Good Output
VPGL PGOOD Voltage Low IPGOOD = 2mA 0.1 0.3 V IPGOOD PGOOD Leakage Current VPGOOD = 5.5V 2 µA V + PG PGOOD Trip Level VFB1, VFB2 with Respect to Set Output Voltage V + FB1, VFB2 Ramping Up 10 % V + FB1, VFB2 Ramping Down –10 % TDELAY VPGOOD High to Low Delay Time 50 µs TBLANK PGOOD Bad Blanking Time Measure from VID Transition Edge 235 µs
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The LTC3877 is tested in a feedback loop that servos VITH1,2 to a may cause permanent damage to the device. Exposure to any Absolute specified voltage and measures the resultant V + + OSNS1 , VFB2 . Maximum Rating condition for extended periods may affect device
Note 5:
Dynamic supply current is higher due to the gate charge being reliability and lifetime. delivered at the switching frequency. See Applications Information.
Note 2:
TJ is calculated from the ambient temperature TA and power
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay dissipation PD according to the following formula: TJ = TA + (PD • 34°C/W). times are measured using 50% levels.
Note 3:
The LTC3877 is tested under pulsed load conditions such that
Note 7:
The minimum on-time condition is specified for an inductor TJ ≈ TA. The LTC3877E is guaranteed to meet specifications from peak-to-peak ripple current ≥40% of IMAX (see Minimum On-Time 0°C to 85°C junction temperature. Specifications over the –40°C to Considerations in the Applications Information section). 125°C operating junction temperature range are assured by design,
Note 8:
Guaranteed by design. characterization and correlation with statistical process controls. The LTC3877I is guaranteed over the full –40°C to 125°C operating junction
Note 9:
Both VID_EN and SNSD+ pins to GND. In order to obtain 5V at the + temperature range. Note that the maximum ambient temperature output of Channel 1, the VOSNS1 pin must be connected to the mid-point consistent with these specifications is determined by specific operating of an external resistor divider, and the VFB1 pin must be shorted to the conditions in conjunction with board layout, the rated package thermal DIFFOUT pin. impedance and other environmental factors.
Note 10:
SNSD+ pin to VOUT.
Note 11:
SNSD+ pin to GND. 3877f For more information www.linear.com/LTC3877 5
e lecTrical characTerisTics The
l
denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are at TA = 25°C (Note 3). VIN = 15V, VRUN = 5V unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS INTVCC Linear Regulator
VINTVCC Internal LDO Output Voltage 6V < VIN < 38V 5.3 5.5 5.7 V VLDO INT INTVCC Load Regulation ICC = 0 to 20mA 0.5 2.0 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Rising l 4.5 4.7 V VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5.5V 40 100 mV VLDOHYS EXTVCC Hysteresis 300 mV
Oscillator and Phase-Locked Loop
fNOM Nominal Frequency VFREQ = 1.22V 575 625 675 kHz fRANGE PLL SYNC Range l 250 1000 kHz VSYNC MODE/PLLIN Sync Input Threshold VSYNC Rising 1.6 V VSYNC Falling 1 V RMODE/PLLIN MODE/PLLIN Input Resistance 250 kΩ IFREQ Frequency Setting Current VFREQ = 1.2V 9 10 11 μA VCLKOUT High Output Voltage VINTVCC = 5.5V 4 5.5 V Low Output Voltage 0 0.2 V Φ2 – Φ1 Channel 2 to Channel 1 Phase Delay VPHSMD = 0V 180 Deg VPHSMD = Float 180 Deg VPHSMD = INTVCC 240 Deg ΦCLKOUT – Φ1 CLKOUT to Channel 1 Phase Delay VPHSMD = 0V 60 Deg VPHSMD = Float 90 Deg VPHSMD = INTVCC 120 Deg
Power Good Output
VPGL PGOOD Voltage Low IPGOOD = 2mA 0.1 0.3 V IPGOOD PGOOD Leakage Current VPGOOD = 5.5V 2 µA V + PG PGOOD Trip Level VFB1, VFB2 with Respect to Set Output Voltage V + FB1, VFB2 Ramping Up 10 % V + FB1, VFB2 Ramping Down –10 % TDELAY VPGOOD High to Low Delay Time 50 µs TBLANK PGOOD Bad Blanking Time Measure from VID Transition Edge 235 µs
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The LTC3877 is tested in a feedback loop that servos VITH1,2 to a may cause permanent damage to the device. Exposure to any Absolute specified voltage and measures the resultant V + + OSNS1 , VFB2 . Maximum Rating condition for extended periods may affect device
Note 5:
Dynamic supply current is higher due to the gate charge being reliability and lifetime. delivered at the switching frequency. See Applications Information.
Note 2:
TJ is calculated from the ambient temperature TA and power
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay dissipation PD according to the following formula: TJ = TA + (PD • 34°C/W). times are measured using 50% levels.
Note 3:
The LTC3877 is tested under pulsed load conditions such that
Note 7:
The minimum on-time condition is specified for an inductor TJ ≈ TA. The LTC3877E is guaranteed to meet specifications from peak-to-peak ripple current ≥40% of IMAX (see Minimum On-Time 0°C to 85°C junction temperature. Specifications over the –40°C to Considerations in the Applications Information section). 125°C operating junction temperature range are assured by design,
Note 8:
Guaranteed by design. characterization and correlation with statistical process controls. The LTC3877I is guaranteed over the full –40°C to 125°C operating junction
Note 9:
Both VID_EN and SNSD+ pins to GND. In order to obtain 5V at the + temperature range. Note that the maximum ambient temperature output of Channel 1, the VOSNS1 pin must be connected to the mid-point consistent with these specifications is determined by specific operating of an external resistor divider, and the VFB1 pin must be shorted to the conditions in conjunction with board layout, the rated package thermal DIFFOUT pin. impedance and other environmental factors.
Note 10:
SNSD+ pin to VOUT.
Note 11:
SNSD+ pin to GND. 3877f For more information www.linear.com/LTC3877 5
