Datasheet LTC3778 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | Wide Operating Range, No RSENSE Step-Down Controller |
| Pages / Page | 24 / 3 — ELECTRICAL CHARACTERISTICS The. denotes specifications which apply over … |
| File Format / Size | PDF / 312 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS The. denotes specifications which apply over the full operating
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LTC3778
ELECTRICAL CHARACTERISTICS The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25
°
C. VIN = 15V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VRUN/SS(ON) RUN Pin Start Threshold ● 0.8 1.5 2 V VRUN/SS(LE) RUN Pin Latchoff Enable Threshold RUN/SS Pin Rising 4 4.5 V VRUN/SS(LT) RUN Pin Latchoff Threshold RUN/SS Pin Falling 3.5 4.2 V IRUN/SS(C) Soft-Start Charge Current – 0.5 – 1.2 –3 µA IRUN/SS(D) Soft-Start Discharge Current 0.8 1.8 3 µA VIN(UVLO) Undervoltage Lockout Threshold VIN Falling ● 3.4 3.9 V VIN(UVLOR) Undervoltage Lockout Threshold VIN Rising ● 3.5 4 V TG RUP TG Driver Pull-Up On Resistance TG High 2 3 Ω TG RDOWN TG Driver Pull-Down On Resistance TG Low 2 3 Ω BG RUP BG Driver Pull-Up On Resistance BG High 3 4 Ω BG RDOWN BG Driver Pull-Down On Resistance BG Low 1 2 Ω TG tr TG Rise Time CLOAD = 3300pF 20 ns TG tf TG Fall Time CLOAD = 3300pF 20 ns BG tr BG Rise Time CLOAD = 3300pF 20 ns BG tf BG Fall Time CLOAD = 3300pF 20 ns
Internal VCC Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V, VEXTVCC = 4V ● 4.7 5 5.3 V ∆VLDO(LOADREG) Internal VCC Load Regulation ICC = 0mA to 20mA, VEXTVCC = 4V – 0.1 ±2 % VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, VEXTVCC Rising ● 4.5 4.7 V ∆VEXTVCC EXTVCC Switch Drop Voltage ICC = 20mA, VEXTVCC = 5V 150 300 mV ∆VEXTVCC(HYS) EXTVCC Switchover Hysteresis 200 mV
PGOOD Output
∆VFBH PGOOD Upper Threshold VFB Rising 7.5 10 12.5 % ∆VFBL PGOOD Lower Threshold VFB Falling – 7.5 – 10 – 12.5 % ∆VFB(HYS) PGOOD Hysteresis VFB Returning 1 2.5 % VPGL PGOOD Low Voltage IPGOOD = 5mA 0.15 0.4 V
Note 1:
Absolute Maximum Ratings are those values beyond which the life of
Note 3:
The LTC3778 is tested in a feedback loop that adjusts VFB to achieve a device may be impaired. a specified error amplifier output voltage (ITH).
Note 2:
TJ is calculated from the ambient temperature TA and power
Note 4:
The LTC3778E is guaranteed to meet performance specifications from dissipation PD as follows: 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature LTC3778E: T range are assured by design, characterization and correlation with statistical J = TA + (PD • 110°C/W) process controls. 3778f 3
ELECTRICAL CHARACTERISTICS The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25
°
C. VIN = 15V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VRUN/SS(ON) RUN Pin Start Threshold ● 0.8 1.5 2 V VRUN/SS(LE) RUN Pin Latchoff Enable Threshold RUN/SS Pin Rising 4 4.5 V VRUN/SS(LT) RUN Pin Latchoff Threshold RUN/SS Pin Falling 3.5 4.2 V IRUN/SS(C) Soft-Start Charge Current – 0.5 – 1.2 –3 µA IRUN/SS(D) Soft-Start Discharge Current 0.8 1.8 3 µA VIN(UVLO) Undervoltage Lockout Threshold VIN Falling ● 3.4 3.9 V VIN(UVLOR) Undervoltage Lockout Threshold VIN Rising ● 3.5 4 V TG RUP TG Driver Pull-Up On Resistance TG High 2 3 Ω TG RDOWN TG Driver Pull-Down On Resistance TG Low 2 3 Ω BG RUP BG Driver Pull-Up On Resistance BG High 3 4 Ω BG RDOWN BG Driver Pull-Down On Resistance BG Low 1 2 Ω TG tr TG Rise Time CLOAD = 3300pF 20 ns TG tf TG Fall Time CLOAD = 3300pF 20 ns BG tr BG Rise Time CLOAD = 3300pF 20 ns BG tf BG Fall Time CLOAD = 3300pF 20 ns
Internal VCC Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V, VEXTVCC = 4V ● 4.7 5 5.3 V ∆VLDO(LOADREG) Internal VCC Load Regulation ICC = 0mA to 20mA, VEXTVCC = 4V – 0.1 ±2 % VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, VEXTVCC Rising ● 4.5 4.7 V ∆VEXTVCC EXTVCC Switch Drop Voltage ICC = 20mA, VEXTVCC = 5V 150 300 mV ∆VEXTVCC(HYS) EXTVCC Switchover Hysteresis 200 mV
PGOOD Output
∆VFBH PGOOD Upper Threshold VFB Rising 7.5 10 12.5 % ∆VFBL PGOOD Lower Threshold VFB Falling – 7.5 – 10 – 12.5 % ∆VFB(HYS) PGOOD Hysteresis VFB Returning 1 2.5 % VPGL PGOOD Low Voltage IPGOOD = 5mA 0.15 0.4 V
Note 1:
Absolute Maximum Ratings are those values beyond which the life of
Note 3:
The LTC3778 is tested in a feedback loop that adjusts VFB to achieve a device may be impaired. a specified error amplifier output voltage (ITH).
Note 2:
TJ is calculated from the ambient temperature TA and power
Note 4:
The LTC3778E is guaranteed to meet performance specifications from dissipation PD as follows: 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature LTC3778E: T range are assured by design, characterization and correlation with statistical J = TA + (PD • 110°C/W) process controls. 3778f 3
