Datasheet LTC3808 (Analog Devices) - 3
| Hersteller | Analog Devices |
| Beschreibung | No RSENSE , Low EMI, Synchronous DC/DC Controller with Output Tracking |
| Seiten / Seite | 28 / 3 — ELECTRICAL CHARACTERISTICS The |
| Dateiformat / Größe | PDF / 386 Kb |
| Dokumentensprache | Englisch |
ELECTRICAL CHARACTERISTICS The
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LTC3808
ELECTRICAL CHARACTERISTICS The
●
indicates specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 4.2V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
Overvoltage Protect Hysteresis 20 mV Auxiliary Feedback Threshold 0.325 0.4 0.475 V Top Gate (TG) Drive Rise Time CL = 3000pF 40 ns Top Gate (TG) Drive Fall Time CL = 3000pF 40 ns Bottom Gate (BG) Drive Rise Time CL = 3000pF 50 ns Bottom Gate (BG) Drive Fall Time CL = 3000pF 40 ns Maximum Current Sense Voltage (∆VSENSE(MAX)) IPRG = Floating (Note 6) ● 110 125 140 mV (SENSE+ – SW) IPRG = 0V (Note 6) ● 70 85 100 mV IPRG = VIN (Note 6) ● 185 204 223 mV Soft-Start Time (Internal) Time for VFB to Ramp from 0.05V to 0.55V 0.5 0.74 0.9 ms
Oscillator and Phase-Locked Loop
Oscillator Frequency Unsynchronized (SYNC/MODE Not Clocked) PLLLPF = Floating 480 550 600 kHz PLLLPF = 0V 260 300 340 kHz PLLLPF = VIN 650 750 825 kHz Phase-Locked Loop Lock Range SYNC/MODE Clocked Minimum Synchronizable Frequency 200 250 kHz Maximum Synchronizible Frequency 750 1000 kHz Phase Detector Output Current Sinking fOSC > fSYNC/MODE –3 µA Sourcing fOSC < fSYNC/MODE 3 µA Spread Spectrum Frequency Range Minimum Switching Frequency 460 kHz Maximum Switching Frequency 635 kHz SYNC/MODE Pull-Down Current SYNC/MODE = 2.2V 2.6 µA
PGOOD Output
PGOOD Voltage Low IPGOOD Sinking 1mA 50 mV PGOOD Trip Level VFB with Respect to Set Output Voltage VFB < 0.6V, Ramping Positive –13 –10.0 –7 % VFB < 0.6V, Ramping Negative –16 –13.3 –10 % VFB > 0.6V, Ramping Negative 7 10.0 13 % VFB > 0.6V, Ramping Positive 10 13.3 16 %
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 4:
Dynamic supply current is higher due to gate charge being of a device may be impaired. delivered at the switching frequency.
Note 2:
The LTC3808E is guaranteed to meet specified performance from
Note 5:
The LTC3808 is tested in a feedback loop that servos ITH to a 0°C to 70°C. Specifications over the –40°C to 85°C operating range are specified voltage and measures the resultant VFB voltage. assured by design characterization, and correlation with statistical process
Note 6:
Peak current sense voltage is reduced dependent on duty cycle to controls. a percentage of value as shown in Figure 1.
Note 3:
TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: TJ = TA + (PD • θJA °C/W) 3808f 3
ELECTRICAL CHARACTERISTICS The
●
indicates specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 4.2V unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
Overvoltage Protect Hysteresis 20 mV Auxiliary Feedback Threshold 0.325 0.4 0.475 V Top Gate (TG) Drive Rise Time CL = 3000pF 40 ns Top Gate (TG) Drive Fall Time CL = 3000pF 40 ns Bottom Gate (BG) Drive Rise Time CL = 3000pF 50 ns Bottom Gate (BG) Drive Fall Time CL = 3000pF 40 ns Maximum Current Sense Voltage (∆VSENSE(MAX)) IPRG = Floating (Note 6) ● 110 125 140 mV (SENSE+ – SW) IPRG = 0V (Note 6) ● 70 85 100 mV IPRG = VIN (Note 6) ● 185 204 223 mV Soft-Start Time (Internal) Time for VFB to Ramp from 0.05V to 0.55V 0.5 0.74 0.9 ms
Oscillator and Phase-Locked Loop
Oscillator Frequency Unsynchronized (SYNC/MODE Not Clocked) PLLLPF = Floating 480 550 600 kHz PLLLPF = 0V 260 300 340 kHz PLLLPF = VIN 650 750 825 kHz Phase-Locked Loop Lock Range SYNC/MODE Clocked Minimum Synchronizable Frequency 200 250 kHz Maximum Synchronizible Frequency 750 1000 kHz Phase Detector Output Current Sinking fOSC > fSYNC/MODE –3 µA Sourcing fOSC < fSYNC/MODE 3 µA Spread Spectrum Frequency Range Minimum Switching Frequency 460 kHz Maximum Switching Frequency 635 kHz SYNC/MODE Pull-Down Current SYNC/MODE = 2.2V 2.6 µA
PGOOD Output
PGOOD Voltage Low IPGOOD Sinking 1mA 50 mV PGOOD Trip Level VFB with Respect to Set Output Voltage VFB < 0.6V, Ramping Positive –13 –10.0 –7 % VFB < 0.6V, Ramping Negative –16 –13.3 –10 % VFB > 0.6V, Ramping Negative 7 10.0 13 % VFB > 0.6V, Ramping Positive 10 13.3 16 %
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 4:
Dynamic supply current is higher due to gate charge being of a device may be impaired. delivered at the switching frequency.
Note 2:
The LTC3808E is guaranteed to meet specified performance from
Note 5:
The LTC3808 is tested in a feedback loop that servos ITH to a 0°C to 70°C. Specifications over the –40°C to 85°C operating range are specified voltage and measures the resultant VFB voltage. assured by design characterization, and correlation with statistical process
Note 6:
Peak current sense voltage is reduced dependent on duty cycle to controls. a percentage of value as shown in Figure 1.
Note 3:
TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: TJ = TA + (PD • θJA °C/W) 3808f 3