Datasheet LT1512 (Analog Devices) - 3

LT1512
elecTrical characTerisTics The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 5V, VC = 0.6V, VFB = VREF, IFB = 0V, VSW and S/S pins open, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIREF IFB Reference Voltage Measured at IFB Pin –107 –100 –93 mV VFB = 0V, VC = 0.8V l –110 –100 –90 mV IFB Input Current VIFB = VIREF (Note 3) l 10 25 35 µA IFB Reference Voltage Line Regulation 2.7V ≤ VIN ≤ 25V, VC = 0.8V l 0.01 0.05 %/V gm Error Amplifier Transconductance ∆IC = ±25µA 1100 1500 1900 µmho l 700 2300 µmho Error Amplifier Source Current VFB = VREF – 150mV, VC = 1.5V l 120 200 350 µA Error Amplifier Sink Current VFB = VREF + 150mV, VC = 1.5V l 1400 2400 µA Error Amplifier Clamp Voltage High Clamp, VFB = 1V 1.70 1.95 2.30 V Low Clamp, VFB = 1.5V 0.25 0.40 0.52 V AV Error Amplifier Voltage Gain 500 V/V VC Pin Threshold Duty Cycle = 0% 0.8 1 1.25 V f Switching Frequency 2.7V ≤ VIN ≤ 25V 450 500 550 kHz 0°C ≤ TJ ≤ 125°C l 430 500 580 kHz –40°C ≤ TJ < 0°C (LT1512I) 400 580 kHz Maximum Switch Duty Cycle l 85 95 % Switch Current Limit Blanking Time 130 260 ns BV Output Switch Breakdown Voltage 0°C ≤ TJ ≤ 125°C l 40 47 V –40°C ≤ TJ < 20°C (LT1512I) 35 V VSAT Output Switch ON Resistance ISw = 2A l 0.5 0.8 Ω ILIM Switch Current Limit Duty Cycle = 50% l 1.5 1.9 2.7 A Duty Cycle = 80% (Note 4) l 1.3 1.7 2.5 A ∆IIN Supply Current Increase During Switch ON Time 15 25 mA/A ∆ISw Control Voltage to Switch Current Transconductance 2 A/V Minimum Input Voltage l 2.4 2.7 V IQ Supply Current 2.7V ≤ VIN ≤ 25V l 4 5.5 mA Shutdown Supply Current 2.7V ≤ VIN ≤ 25V, VS/S ≤ 0.6V 0°C ≤ TJ ≤ 125°C l 12 30 µA –40°C ≤ TJ ≤ 0°C (LT1512I) 50 µA Shutdown Threshold 2.7V ≤ VIN ≤ 25V l 0.6 1.3 2 V Shutdown Delay l 5 12 25 µs S/S Pin Input Current 0V ≤ VS/S ≤ 5V l –10 15 µA Synchronization Frequency Range l 600 800 kHz
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings Maximum allowable ambient temperature may be limited by power may cause permanent damage to the device. Exposure to any Absolute dissipation. Parts may not necessarily be operated simultaneously Maximum Rating condition for extended periods may affect device at maximum power dissipation and maximum ambient temperature. reliability and lifetime. Temperature rise calculations must be done as shown in the Applications
Note 2:
Commercial devices are guaranteed over 0°C to 125°C junction Information section to ensure that maximum junction temperature does temperature range and 0°C to 70°C ambient temperature range. These not exceed 125°C limit. with high power dissipation, maximum ambient parts are also designed, characterized and expected to operate over the temperature may be less than 70°C. –20°C to 85°C extended ambient temperature range, but are not tested at
Note 3:
The IFB pin is servoed to its regulating state with VC = 0.8V. –20°C or 85°C. Devices with full guaranteed electrical specifications over
Note 4:
For duty cycles (DC) between 50% and 85%, minimum guaranteed the ambient temperature range –40°C to 85°C are available as industrial switch current is given by ILIM = 0.667 (2.75 – DC). parts with an “I” suffix. 1512fc For more information www.linear.com/LT1512 3 Document Outline Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts