Datasheet LT3800 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | High-Voltage Synchronous Current Mode Step-Down Controller |
| Pages / Page | 24 / 5 — TYPICAL PERFORMANCE CHARACTERISTICS. VCC UVLO Threshold (Rising). Error … |
| File Format / Size | PDF / 265 Kb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS. VCC UVLO Threshold (Rising). Error Amp Transconductance. vs Temperature
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LT3800
TYPICAL PERFORMANCE CHARACTERISTICS VCC UVLO Threshold (Rising) Error Amp Transconductance vs Temperature ICC vs VCC (SHDN = 0V) vs Temperature
6.30 25 380 TA = 25°C 20 ANCE (μmho) 6.25 360 15 (μA) I CC 10 6.20 340 UVLO THRESHOLD, RISING (V) 5 CCV ERROR AMP TRANSCONDUCT 6.15 0 320 –50 –25 0 25 50 75 100 125 0 2 4 6 8 10 12 14 16 18 20 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) VCC (V) TEMPERATURE (°C) 3800 G07 3800 G12 3800 G08
Operating Frequency Error Amp Reference I + – (SENSE + SENSE ) vs VSENSE(CM) vs Temperature vs Temperature
800 220 1.232 TA = 25°C 600 1.231 210 (μA) 400 ) – 1.230 200 200 + SENSE + 1.229 0 TING FREQUENCY (kHz) I (SENSE 190 ERROR AMP REFERENCE (V) 1.228 –200 OPERA –400 180 1.227 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 VSENSE(CM) (V) TEMPERATURE (°C) TEMPERATURE (°C) 3800 G09 3800 G10 3800 G11
PIN FUNCTIONS VIN (Pin 1):
Converter Input Supply.
CSS (Pin 4):
Soft-Start AC Coupling Capacitor Input. Connect capacitor (C
NC (Pin 2):
No Connection. SS) in series with a 200k resistor from pin to converter output (VOUT). Controls converter
SHDN (Pin 3):
Precision Shutdown Pin. Enable threshold start-up output voltage slew rate (∆VOUT/∆t). Slew rate is 1.35V (rising) with 120mV of input hysteresis. When corresponds to 2μA average current through the soft-start in shutdown mode, all internal IC functions are disabled. coupling capacitor. The capacitor value for a desired output The precision threshold allows use of the SHDN pin to startup slew rate follows the relation: incorporate UVLO functions. If the SHDN pin is pulled C below 0.7V, the IC enters a low current shutdown mode SS = 2μA/(∆VOUT/∆t) with IVIN < 10μA. In low-current shutdown, the IC will Shorting this pin to SGND disables the soft-start function sink 20μA from the VCC pin until that local supply has
BURST_EN (Pin 5):
Burst Mode Operation Enable Pin. collapsed. Typical pin input bias current is <10nA and the This pin also controls reverse-inhibit mode of operation. pin is internally clamped to 6V. When the pin voltage is below 0.5V, Burst Mode operation 3800fc 5 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS FUNCTIONAL DIAGRAM APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS
TYPICAL PERFORMANCE CHARACTERISTICS VCC UVLO Threshold (Rising) Error Amp Transconductance vs Temperature ICC vs VCC (SHDN = 0V) vs Temperature
6.30 25 380 TA = 25°C 20 ANCE (μmho) 6.25 360 15 (μA) I CC 10 6.20 340 UVLO THRESHOLD, RISING (V) 5 CCV ERROR AMP TRANSCONDUCT 6.15 0 320 –50 –25 0 25 50 75 100 125 0 2 4 6 8 10 12 14 16 18 20 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) VCC (V) TEMPERATURE (°C) 3800 G07 3800 G12 3800 G08
Operating Frequency Error Amp Reference I + – (SENSE + SENSE ) vs VSENSE(CM) vs Temperature vs Temperature
800 220 1.232 TA = 25°C 600 1.231 210 (μA) 400 ) – 1.230 200 200 + SENSE + 1.229 0 TING FREQUENCY (kHz) I (SENSE 190 ERROR AMP REFERENCE (V) 1.228 –200 OPERA –400 180 1.227 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 VSENSE(CM) (V) TEMPERATURE (°C) TEMPERATURE (°C) 3800 G09 3800 G10 3800 G11
PIN FUNCTIONS VIN (Pin 1):
Converter Input Supply.
CSS (Pin 4):
Soft-Start AC Coupling Capacitor Input. Connect capacitor (C
NC (Pin 2):
No Connection. SS) in series with a 200k resistor from pin to converter output (VOUT). Controls converter
SHDN (Pin 3):
Precision Shutdown Pin. Enable threshold start-up output voltage slew rate (∆VOUT/∆t). Slew rate is 1.35V (rising) with 120mV of input hysteresis. When corresponds to 2μA average current through the soft-start in shutdown mode, all internal IC functions are disabled. coupling capacitor. The capacitor value for a desired output The precision threshold allows use of the SHDN pin to startup slew rate follows the relation: incorporate UVLO functions. If the SHDN pin is pulled C below 0.7V, the IC enters a low current shutdown mode SS = 2μA/(∆VOUT/∆t) with IVIN < 10μA. In low-current shutdown, the IC will Shorting this pin to SGND disables the soft-start function sink 20μA from the VCC pin until that local supply has
BURST_EN (Pin 5):
Burst Mode Operation Enable Pin. collapsed. Typical pin input bias current is <10nA and the This pin also controls reverse-inhibit mode of operation. pin is internally clamped to 6V. When the pin voltage is below 0.5V, Burst Mode operation 3800fc 5 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS FUNCTIONAL DIAGRAM APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS
