Datasheet LT3958 (Analog Devices) - 3

LT3958
elecTrical characTerisTics The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 24V, EN/UVLO = 24V, SENSE2 = 0V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Operating Range 5 80 V VIN Shutdown IQ EN/UVLO = 0V 0.1 1 µA EN/UVLO = 1.15V 6 µA VIN Operating IQ VC = 0.3V, RT = 41.2k 1.6 2.2 mA VIN Operating IQ with Internal LDO Disabled VC = 0.3V, RT = 41.2k, INTVCC = 7.5V 350 400 µA SW Pin Current Limit SENSE2 = SENSE1 l 3.3 4.0 4.6 A SW Pin On Voltage ISW = 2A 180 mV SENSE2 Input Bias Current Current Out of Pin –65 µA
Error Amplifier
FBX Regulation Voltage (VFBX(REG)) FBX > 0V (Note 3) l 1.569 1.6 1.631 V FBX < 0V (Note 3) l –0.816 –0.800 –0.784 V FBX Overvoltage Lockout FBX > 0V (Note 4) 6 8 10 % FBX < 0V (Note 4) 7 11 14 % FBX Pin Input Current FBX = 1.6V (Note 3) 70 100 nA FBX = –0.8V (Note 3) –10 10 nA Transconductance gm (∆IVC/∆FBX) (Note 3) 230 µS VC Output Impedance (Note 3) 5 MΩ VFBX Line Regulation (∆VFBX/[∆VIN • VFBX(REG)]) FBX > 0V, 5V < VIN < 80V (Notes 3, 6) 0.006 0.03 %/V FBX < 0V, 5V < VIN < 80V (Notes 3, 6) 0.005 0.038 %/V VC Current Mode Gain (∆VVC/∆VSENSE) 10 V/V VC Source Current VC = 1.5V, FBX = 0V, Current Out of Pin –15 µA VC Sink Current FBX = 1.7V 12 µA FBX = –0.85V 11 µA
Oscillator
Switching Frequency RT = 140k to SGND, FBX = 1.6V, VC = 1.5V 80 100 120 kHz RT = 41.2k to SGND, FBX = 1.6V, VC = 1.5V 270 300 330 kHz RT = 10.5k to SGND, FBX = 1.6V, VC = 1.5V 850 1000 1200 kHz RT Voltage FBX = 1.6V 1.2 V SW Minimum Off-Time 200 275 ns SW Minimum On-Time 250 300 ns SYNC Input Low 0.4 SYNC Input High 1.5 SS Pull-Up Current SS = 0V, Current Out of Pin –10 µA
Low Dropout Regulator
INTVCC Regulation Voltage l 7 7.2 7.4 V INTVCC Undervoltage Lockout Threshold Falling INTVCC 3.55 3.75 4.00 V UVLO Hysteresis 0.15 V INTVCC Overvoltage Lockout Threshold 11.5 12.8 V 3958fa For more information www.linear.com/LT3958 3 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Typical Applications Related Parts