Datasheet LTC1735-1 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | High Efficiency Synchronous Step-Down Switching Regulator |
| Pages / Page | 28 / 3 — ELECTRICAL CHARACTERISTICS The. denotes specifications which apply over … |
| File Format / Size | PDF / 356 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS The. denotes specifications which apply over the full operating
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LTC1735-1
ELECTRICAL CHARACTERISTICS The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 15V, VRUN/SS = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
TG Transition Time: (Note 7) TG tr Rise Time CLOAD = 3300pF 50 90 ns TG tf Fall Time CLOAD = 3300pF 50 90 ns BG Transition Time: (Note 7) BG tr Rise Time CLOAD = 3300pF 50 90 ns BG tf Fall Time CLOAD = 3300pF 40 80 ns TG/BG T1D Top Gate Off to Synchronous CLOAD = 3300pF Each Driver 100 ns Gate-On Delay Time TG/BG T2D Synchronous Gate Off to Top CLOAD = 3300pF Each Driver 70 ns Gate-On Delay Time
Internal VCC Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V, VEXTVCC = 4V 5.0 5.2 5.4 V VLDO(INT) INTVCC Load Regulation ICC = 0mA to 20mA, VEXTVCC = 4V 0.2 1 % VLDO(EXT) EXTVCC Drop Voltage ICC = 20mA, VEXTVCC = 5V 130 200 mV VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, EXTVCC Ramping Positive ● 4.5 4.7 V VEXTVCC(HYS) EXTVCC Hysteresis 0.2 V
Oscillator
fOSC Oscillator Frequency (Note 6), COSC = 43pF 265 300 335 kHz fH/fOSC Maximum Sync Frequency Ratio 1.3
PGOOD Pin
VPG(SYNC) PGOOD Threshold for Sync Ramping Negative 0.9 1.2 V VPG(FC) PGOOD Threshold for Force Cont. 0.76 0.8 0.84 V VPGL PGOOD Voltage Low IPGOOD = 2mA 110 200 mV IPGOOD PGOOD Pull-Up Current VPGOOD = 0.85V – 0.17 µA VPG PGOOD Trip Level VOSENSE With Respect to Set Output Voltage VOSENSE Ramping Negative – 6.0 –7.5 –9.5 % VOSENSE Ramping Positive 6.0 7.5 9.5 %
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 5:
Dynamic supply current is higher due to the gate charge being of the device may be impaired. delivered at the switching frequency. See Applications Information.
Note 2:
TJ is calculated from the ambient temperature TA and power
Note 6:
Oscillator frequency is tested by measuring the COSC charge dissipation PD according to the following formulas: current (IOSC) and applying the formula: LTC1735CS-1, LTC1735IS-1: TJ = TA + (PD • 110 °C/W) – 1 8 477 108 1 1 LTC1735CGN-1, LTC1735IGN-1: T . ( ) J = TA + (PD • 130°C/W) f kHz = OSC ( ) + C p ( F) + 11 I I
Note 3:
The LTC1735-1 is tested in a feedback loop that servos V OSC CHG DIS OSENSE to the balance point for the error amplifier (VITH = 1.2V).
Note 7:
Rise and fall times are measured using 10% to 90% levels.
Note 4:
The minimum on-time condition corresponds to an inductor Delay times are measured using 50% levels. peak-to-peak ripple current > 40% of IMAX (see Minimum On-Time Considerations in the Applications Information section). 3
ELECTRICAL CHARACTERISTICS The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 15V, VRUN/SS = 5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
TG Transition Time: (Note 7) TG tr Rise Time CLOAD = 3300pF 50 90 ns TG tf Fall Time CLOAD = 3300pF 50 90 ns BG Transition Time: (Note 7) BG tr Rise Time CLOAD = 3300pF 50 90 ns BG tf Fall Time CLOAD = 3300pF 40 80 ns TG/BG T1D Top Gate Off to Synchronous CLOAD = 3300pF Each Driver 100 ns Gate-On Delay Time TG/BG T2D Synchronous Gate Off to Top CLOAD = 3300pF Each Driver 70 ns Gate-On Delay Time
Internal VCC Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V, VEXTVCC = 4V 5.0 5.2 5.4 V VLDO(INT) INTVCC Load Regulation ICC = 0mA to 20mA, VEXTVCC = 4V 0.2 1 % VLDO(EXT) EXTVCC Drop Voltage ICC = 20mA, VEXTVCC = 5V 130 200 mV VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, EXTVCC Ramping Positive ● 4.5 4.7 V VEXTVCC(HYS) EXTVCC Hysteresis 0.2 V
Oscillator
fOSC Oscillator Frequency (Note 6), COSC = 43pF 265 300 335 kHz fH/fOSC Maximum Sync Frequency Ratio 1.3
PGOOD Pin
VPG(SYNC) PGOOD Threshold for Sync Ramping Negative 0.9 1.2 V VPG(FC) PGOOD Threshold for Force Cont. 0.76 0.8 0.84 V VPGL PGOOD Voltage Low IPGOOD = 2mA 110 200 mV IPGOOD PGOOD Pull-Up Current VPGOOD = 0.85V – 0.17 µA VPG PGOOD Trip Level VOSENSE With Respect to Set Output Voltage VOSENSE Ramping Negative – 6.0 –7.5 –9.5 % VOSENSE Ramping Positive 6.0 7.5 9.5 %
Note 1:
Absolute Maximum Ratings are those values beyond which the life
Note 5:
Dynamic supply current is higher due to the gate charge being of the device may be impaired. delivered at the switching frequency. See Applications Information.
Note 2:
TJ is calculated from the ambient temperature TA and power
Note 6:
Oscillator frequency is tested by measuring the COSC charge dissipation PD according to the following formulas: current (IOSC) and applying the formula: LTC1735CS-1, LTC1735IS-1: TJ = TA + (PD • 110 °C/W) – 1 8 477 108 1 1 LTC1735CGN-1, LTC1735IGN-1: T . ( ) J = TA + (PD • 130°C/W) f kHz = OSC ( ) + C p ( F) + 11 I I
Note 3:
The LTC1735-1 is tested in a feedback loop that servos V OSC CHG DIS OSENSE to the balance point for the error amplifier (VITH = 1.2V).
Note 7:
Rise and fall times are measured using 10% to 90% levels.
Note 4:
The minimum on-time condition corresponds to an inductor Delay times are measured using 50% levels. peak-to-peak ripple current > 40% of IMAX (see Minimum On-Time Considerations in the Applications Information section). 3
