Datasheet LTC1876 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | High Efficiency, 2-Phase, Dual Synchronous Step-Down Switching Controller and Step-Up Regulator |
| Pages / Page | 36 / 3 — ELECTRICAL CHARACTERISTICS The |
| File Format / Size | PDF / 372 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS The
Model Line for this Datasheet
Text Version of Document
LTC1876
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 15V, VRUN/SS1, 2 = 5V, AUXVIN = 3V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
UVLO Undervoltage Lockout VIN Ramping Down ● 3.5 4 V VOVL Overvoltage Feedback Threshold Measured at VOSENSE1, 2 ● 0.84 0.86 0.88 V I – – + + SENSE Sense Pins Total Source Current (Each Channel); VSENSE1 , 2 = VSENSE1 , 2 = 0V –85 –60 µA VSTBYMD MS Master Shutdown Threshold VSTBYMD Ramping Down 0.4 0.6 V VSTBYMD KA Keep-Alive Power On-Threshold VSTBYMD Ramping Up, RUNSS1, 2 = 0V 1.5 2 V DFMAX Maximum Duty Factor In Dropout 98 99.4 % IRUN/SS1, 2 Soft-Start Charge Current VRUN/SS1, 2 = 1.9V 0.5 1.2 µA VRUN/SS1, 2 ON RUN/SS Pin ON Threshold VRUN/SS1, VRUN/SS2 Rising 1.0 1.5 1.9 V VRUN/SS1, 2 LT RUN/SS Pin Latchoff Arming Threshold VRUN/SS1, VRUN/SS2 Rising from 3V 4.1 4.5 V ISCL1, 2 RUN/SS Discharge Current Soft Short Condition VOSENSE1, 2 = 0.5V; 0.5 2 4 µA VRUN/SS1, 2 = 4.5V ISDLHO Shutdown Latch Disable Current VOSENSE1, 2 =0.5V 1.6 5 µA V – – SENSE(MAX) Maximum Current Sense Threshold VOSENSE1, 2 = 0.7V, VSENSE1 , 2 = 5V ● 62 75 88 mV TG Transition Time: TG1, 2 tr Rise Time CLOAD = 3300pF 50 90 ns TG1, 2 tf Fall Time CLOAD = 3300pF 50 90 ns BG Transition Time: BG1, 2 tr Rise Time CLOAD = 3300pF 40 90 ns BG1, 2 tf Fall Time CLOAD = 3300pF 40 80 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Synchronous Switch-On Delay Time CLOAD = 3300pF Each Driver 90 ns BG/TG t2D Bottom Gate Off to Top Gate On Delay Top Switch-On Delay Time CLOAD = 3300pF Each Driver 90 ns tON(MIN) Minimum ON-Time Tested with a Square Wave (Note 7) 180 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V, VEXTVCC = 4V 4.8 5.0 5.2 V VLDO INT INTVCC Load Regulation ICC = 0 to 20mA, VEXTVCC = 4V 0.2 1.0 % VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5V 80 160 mV VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, EXTVCC Ramping Positive ● 4.5 4.7 V VLDOHYS EXTVCC Hysteresis 0.2 V
Oscillator
fOSC Oscillator frequency VFREQSET = Open (Note 8) 190 220 250 kHz fLOW Lowest Frequency VFREQSET = 0V 120 140 160 kHz fHIGH Highest Frequency VFREQSET = 2.4V 280 310 360 kHz IFREQSET FREQSET Input Current VFREQSET = 2.4V –2 –1 µA 1876fa 3
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VIN = 15V, VRUN/SS1, 2 = 5V, AUXVIN = 3V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
UVLO Undervoltage Lockout VIN Ramping Down ● 3.5 4 V VOVL Overvoltage Feedback Threshold Measured at VOSENSE1, 2 ● 0.84 0.86 0.88 V I – – + + SENSE Sense Pins Total Source Current (Each Channel); VSENSE1 , 2 = VSENSE1 , 2 = 0V –85 –60 µA VSTBYMD MS Master Shutdown Threshold VSTBYMD Ramping Down 0.4 0.6 V VSTBYMD KA Keep-Alive Power On-Threshold VSTBYMD Ramping Up, RUNSS1, 2 = 0V 1.5 2 V DFMAX Maximum Duty Factor In Dropout 98 99.4 % IRUN/SS1, 2 Soft-Start Charge Current VRUN/SS1, 2 = 1.9V 0.5 1.2 µA VRUN/SS1, 2 ON RUN/SS Pin ON Threshold VRUN/SS1, VRUN/SS2 Rising 1.0 1.5 1.9 V VRUN/SS1, 2 LT RUN/SS Pin Latchoff Arming Threshold VRUN/SS1, VRUN/SS2 Rising from 3V 4.1 4.5 V ISCL1, 2 RUN/SS Discharge Current Soft Short Condition VOSENSE1, 2 = 0.5V; 0.5 2 4 µA VRUN/SS1, 2 = 4.5V ISDLHO Shutdown Latch Disable Current VOSENSE1, 2 =0.5V 1.6 5 µA V – – SENSE(MAX) Maximum Current Sense Threshold VOSENSE1, 2 = 0.7V, VSENSE1 , 2 = 5V ● 62 75 88 mV TG Transition Time: TG1, 2 tr Rise Time CLOAD = 3300pF 50 90 ns TG1, 2 tf Fall Time CLOAD = 3300pF 50 90 ns BG Transition Time: BG1, 2 tr Rise Time CLOAD = 3300pF 40 90 ns BG1, 2 tf Fall Time CLOAD = 3300pF 40 80 ns TG/BG t1D Top Gate Off to Bottom Gate On Delay Synchronous Switch-On Delay Time CLOAD = 3300pF Each Driver 90 ns BG/TG t2D Bottom Gate Off to Top Gate On Delay Top Switch-On Delay Time CLOAD = 3300pF Each Driver 90 ns tON(MIN) Minimum ON-Time Tested with a Square Wave (Note 7) 180 ns
INTVCC Linear Regulator
VINTVCC Internal VCC Voltage 6V < VIN < 30V, VEXTVCC = 4V 4.8 5.0 5.2 V VLDO INT INTVCC Load Regulation ICC = 0 to 20mA, VEXTVCC = 4V 0.2 1.0 % VLDO EXT EXTVCC Voltage Drop ICC = 20mA, VEXTVCC = 5V 80 160 mV VEXTVCC EXTVCC Switchover Voltage ICC = 20mA, EXTVCC Ramping Positive ● 4.5 4.7 V VLDOHYS EXTVCC Hysteresis 0.2 V
Oscillator
fOSC Oscillator frequency VFREQSET = Open (Note 8) 190 220 250 kHz fLOW Lowest Frequency VFREQSET = 0V 120 140 160 kHz fHIGH Highest Frequency VFREQSET = 2.4V 280 310 360 kHz IFREQSET FREQSET Input Current VFREQSET = 2.4V –2 –1 µA 1876fa 3
