Datasheet LT1680 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | High Power DC/DC Step-Up Controller |
| Pages / Page | 16 / 3 — ELECTRICAL CHARACTERISTICS. The |
| File Format / Size | PDF / 228 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The
Model Line for this Datasheet
Text Version of Document
LT1680
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. 12VIN = 12V, VVC = 2V, VFB = VREF = 1.25V, CGATE = 3000pF, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Error Amplifier
VSENSE Peak Current Limit Threshold Measured at Sense Inputs ● 170 190 mV Average Current Limit Threshold Measured at Sense Inputs, VCMSENSE = 10V ● 110 120 130 mV VIAVG Average Current Limit Threshold Measured at IAVG Pin 2.5 V
Current Sense Amplifier
AV Amplifier DC Gain Measured at IAVG Pin 15 V/V VOS Amplifier Input Offset Voltage 2V < VCMSENSE < 60V, ● 0.1 mV SENSE+ – SENSE– = 5mV IBIAS Input Bias Current Sink (VCMSENSE > 5V) ● 45 75 µA Source (VCMSENSE = 0V) ● 700 1200 µA
Oscillator
fO Operating Frequency, Free Run ● 200 kHz Frequency Programming Error fO ≤ 200kHz, RCT = 16.9k, CCT = 1000pF ● – 5 5 % ICT Timing Capacitor Discharge Current LT1680C ● 2.20 2.5 2.75 mA LT1680I ● 2.10 2.5 2.75 mA VSYNC SYNC Input Threshold Rising Edge ● 0.8 2.0 V fSYNC SYNC Frequency Range fSYNC ≤ 200kHz ● fO 1.4fO
Output Drivers
VGATE Undervoltage Output Clamp 12VIN ≤ 8.2V ● 0.4 0.7 V Standby Mode Output Clamp VRUN < 0.5V ● 0.1 V Gate Output On Voltage ● 11 11.9 12 V Gate Output Off Voltage ● 0.4 0.7 V tGATER Gate Output Rise Time ● 60 200 ns tGATEF Gate Output Fall Time ● 60 140 ns
Note 1:
Absolute Maximum Ratings are those values beyond which the life of
Note 2:
Supply current specification does not include external FET gate a device may be impaired. charge currents. Actual supply currents will be higher and vary with operating frequency, operating voltages and the type of external FETs used. See Applications Information. 3
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. 12VIN = 12V, VVC = 2V, VFB = VREF = 1.25V, CGATE = 3000pF, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Error Amplifier
VSENSE Peak Current Limit Threshold Measured at Sense Inputs ● 170 190 mV Average Current Limit Threshold Measured at Sense Inputs, VCMSENSE = 10V ● 110 120 130 mV VIAVG Average Current Limit Threshold Measured at IAVG Pin 2.5 V
Current Sense Amplifier
AV Amplifier DC Gain Measured at IAVG Pin 15 V/V VOS Amplifier Input Offset Voltage 2V < VCMSENSE < 60V, ● 0.1 mV SENSE+ – SENSE– = 5mV IBIAS Input Bias Current Sink (VCMSENSE > 5V) ● 45 75 µA Source (VCMSENSE = 0V) ● 700 1200 µA
Oscillator
fO Operating Frequency, Free Run ● 200 kHz Frequency Programming Error fO ≤ 200kHz, RCT = 16.9k, CCT = 1000pF ● – 5 5 % ICT Timing Capacitor Discharge Current LT1680C ● 2.20 2.5 2.75 mA LT1680I ● 2.10 2.5 2.75 mA VSYNC SYNC Input Threshold Rising Edge ● 0.8 2.0 V fSYNC SYNC Frequency Range fSYNC ≤ 200kHz ● fO 1.4fO
Output Drivers
VGATE Undervoltage Output Clamp 12VIN ≤ 8.2V ● 0.4 0.7 V Standby Mode Output Clamp VRUN < 0.5V ● 0.1 V Gate Output On Voltage ● 11 11.9 12 V Gate Output Off Voltage ● 0.4 0.7 V tGATER Gate Output Rise Time ● 60 200 ns tGATEF Gate Output Fall Time ● 60 140 ns
Note 1:
Absolute Maximum Ratings are those values beyond which the life of
Note 2:
Supply current specification does not include external FET gate a device may be impaired. charge currents. Actual supply currents will be higher and vary with operating frequency, operating voltages and the type of external FETs used. See Applications Information. 3
