Datasheet LTC7821 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Hybrid Step-Down Synchronous Controller |
| Pages / Page | 36 / 4 — ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply … |
| Revision | A |
| File Format / Size | PDF / 1.6 Mb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply over the specified operating
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LTC7821
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = VIN_SENSE = 48V, VRUN = 5V, EXTVCC = 9V, EXT_REF = 5.6V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS INTVCC Linear Regulator
VINTVCC Internal VCC Regulator 10V < VIN < 72V, VEXTVCC = 0V 5.65 5.8 5.95 V VLDOINT INTVCC Load Regulation ICC = 1mA to 50mA, VIN = 12V, VEXTVCC = 0V –0.6 –2 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive, ICC = 1mA 7 V VEXTVCC_HYS EXTVCC Switchover Voltage Hysteresis 200 mV VLDOEXT EXTVCC Load Regulation VEXTVCC = 12V, ICC = 1mA to 50mA –0.6 –2 %
Oscillator and Phase Lock Loop
fNOM Nominal Frequency RFREQ = 68kΩ 440 490 550 kHz fLOW Lowest Frequency VFREQ = 0V 20 50 100 kHz fHIGH Highest Frequency VFREQ = INTVCC 1400 1700 2000 kHz fSYNC_LOW Lowest Synchronizing Frequency 200 kHz fSYNC_HIGH Highest Synchronizing Frequency 1500 KHz IFREQ Frequency Setting Current VFREQ = 0V l –9 –10 –11 µA RMODE/PLLIN MODE/PLLIN Resistance 250 kΩ CLKOUTHIGH CLKOUT High Amplitude 2.4 V CLKOUTLOW CLKOUT Low Amplitude 0 V
PGOOD Output
VPG1 PGOOD 1st Trip Level (with Delay) VFB with Respect to Regulated Voltage VFB Ramping Up (Overvoltage 1st Level) 6 8.5 11 % VFB Ramping Down (Undervoltage 1st –5.5 –7.5 –9.5 % Level) VPG1_HYST PGOOD 1st Trip Level Hysteresis (with Delay) 15 mV VPG2 PGOOD 2nd Trip Level VFB with Respect to Regulated Voltage VFB Ramping Up (Overvoltage 2nd Level) 15 % VFB Ramping Down (Undervoltage 2nd –25 % Level) VPG2_HYST PGOOD 2nd Trip Level Hysteresis 15 mV VPGL PGOOD Voltage Low IPGOOD = 0.6mA 0.4 0.5 V IPGOOD PGOOD Leakage Current VPGOOD = 80V 1 μA
Capacitor Balancing
VTIMER_LOW Voltage At TIMER Pin To Start Capacitor 0.5 V Balancing VTIMER_HIGH Voltage At TIMER Pin To Stop Capacitor 1.25 V Balancing ITIMER TIMER Pin Charge Current VTIMER = 0.9V l –6 –7 –8 µA VTIMER = 2.8V l –3 –3.5 –4 µA VHYS_PRGM Capacitor Balancing Window Comparator VHYS_PRGM = 0V ±0.3 V Threshold VHYS_PRGM = 1.2V ±1.2 V VHYS_PRGM = INTVCC ±0.8 V IHYS_PRGM HYS_PRGM Pin Current VHYS_PRGM = 0V l –9 –10 –11 μA VFAULT FAULT Pin Voltage Low IFAULT = 0.6mA 0.2 0.4 V IFAULT FAULT Leakage Current VFAULT = 80V 1 μA Rev A 4 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Related Parts
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = VIN_SENSE = 48V, VRUN = 5V, EXTVCC = 9V, EXT_REF = 5.6V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS INTVCC Linear Regulator
VINTVCC Internal VCC Regulator 10V < VIN < 72V, VEXTVCC = 0V 5.65 5.8 5.95 V VLDOINT INTVCC Load Regulation ICC = 1mA to 50mA, VIN = 12V, VEXTVCC = 0V –0.6 –2 % VEXTVCC EXTVCC Switchover Voltage EXTVCC Ramping Positive, ICC = 1mA 7 V VEXTVCC_HYS EXTVCC Switchover Voltage Hysteresis 200 mV VLDOEXT EXTVCC Load Regulation VEXTVCC = 12V, ICC = 1mA to 50mA –0.6 –2 %
Oscillator and Phase Lock Loop
fNOM Nominal Frequency RFREQ = 68kΩ 440 490 550 kHz fLOW Lowest Frequency VFREQ = 0V 20 50 100 kHz fHIGH Highest Frequency VFREQ = INTVCC 1400 1700 2000 kHz fSYNC_LOW Lowest Synchronizing Frequency 200 kHz fSYNC_HIGH Highest Synchronizing Frequency 1500 KHz IFREQ Frequency Setting Current VFREQ = 0V l –9 –10 –11 µA RMODE/PLLIN MODE/PLLIN Resistance 250 kΩ CLKOUTHIGH CLKOUT High Amplitude 2.4 V CLKOUTLOW CLKOUT Low Amplitude 0 V
PGOOD Output
VPG1 PGOOD 1st Trip Level (with Delay) VFB with Respect to Regulated Voltage VFB Ramping Up (Overvoltage 1st Level) 6 8.5 11 % VFB Ramping Down (Undervoltage 1st –5.5 –7.5 –9.5 % Level) VPG1_HYST PGOOD 1st Trip Level Hysteresis (with Delay) 15 mV VPG2 PGOOD 2nd Trip Level VFB with Respect to Regulated Voltage VFB Ramping Up (Overvoltage 2nd Level) 15 % VFB Ramping Down (Undervoltage 2nd –25 % Level) VPG2_HYST PGOOD 2nd Trip Level Hysteresis 15 mV VPGL PGOOD Voltage Low IPGOOD = 0.6mA 0.4 0.5 V IPGOOD PGOOD Leakage Current VPGOOD = 80V 1 μA
Capacitor Balancing
VTIMER_LOW Voltage At TIMER Pin To Start Capacitor 0.5 V Balancing VTIMER_HIGH Voltage At TIMER Pin To Stop Capacitor 1.25 V Balancing ITIMER TIMER Pin Charge Current VTIMER = 0.9V l –6 –7 –8 µA VTIMER = 2.8V l –3 –3.5 –4 µA VHYS_PRGM Capacitor Balancing Window Comparator VHYS_PRGM = 0V ±0.3 V Threshold VHYS_PRGM = 1.2V ±1.2 V VHYS_PRGM = INTVCC ±0.8 V IHYS_PRGM HYS_PRGM Pin Current VHYS_PRGM = 0V l –9 –10 –11 μA VFAULT FAULT Pin Voltage Low IFAULT = 0.6mA 0.2 0.4 V IFAULT FAULT Leakage Current VFAULT = 80V 1 μA Rev A 4 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Related Parts
