Datasheet LTC3721-1 (Analog Devices) - 3

LTC3721-1
ELECTRICAL CHARACTERISTICS The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25
°
C. VCC = 9.5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Pulse Width Modulator
ROS Ramp Offset Voltage Measured on COMP, CS = 0V 0.65 V IRMP Ramp Discharge Current CS = 1V, COMP = 0V, CT = 4V 50 mA ISLP Slope Compensation Current Measured on CS, CT = 1V 30 µA CT = 2.25V 68 µA DCMAX Maximum Duty Cycle COMP = 4.5V ● 47 48.2 50 % DCMIN Minimum Duty Cycle COMP = 0V ● 0 % DTADJ Dead-Time 130 ns
Oscillator
OSCI Initial Accuracy TA = 25°C, CT = 270pF 220 250 280 kHz OSCT VCC Variation VCC = 6.5V to 9.5V ● –3 3 % OSCV CT Ramp Amplitude Measured on CT 2.35 V
Error Amplifier
VFB FB Input Voltage COMP = 2.5V, (Note 3) 1.172 1.2 1.22 V FBI FB Input Range Measured on FB, (Note 4) – 0.3 2.5 V AVOL Open-Loop Gain COMP = 1V to 3V, (Note 3) 70 90 dB IIB Input Bias Current COMP = 2.5V, (Note 3) 5 50 nA VOH Output High Load on COMP = –100µA 4.7 4.92 V VOL Output Low Load on COMP = 100µA 0.27 0.5 V ISOURCE Output Source Current COMP = 2.5V 400 700 µA ISINK Output Sink Current COMP = 2.5V 2 5 mA
Reference
VREF Initial Accuracy TA = 25°C, Measured on VREF 4.925 5.00 5.075 V REFLD Load Regulation Load on VREF = 100µA to 5mA 2 15 mV REFLN Line Regulation VCC = 6.5V to 9.5V 1 10 mV REFTV Total Variation Line, Load and Temperature ● 4.900 5.000 5.100 V REFSC Short-Circuit Current VREF Shorted to GND 18 30 45 mA
Push-Pull Outputs
DRVH(x) Output High Voltage IOUT(x) = –100mA 9.2 V DRVL(x) Output Low Voltage IOUT(x) = 100mA 0.17 V RDH(x) Pull-Up Resistance IOUT(x) = –10mA to –100mA 2.9 Ω RDL(x) Pull-Down Resistance IOUT(x) = –10mA to –100mA 1.7 Ω TDR(x) Rise-Time COUT(x) = 1nF 10 ns TDF(x) Fall-Time COUT(x) = 1nF 10 ns
Current Limit and Shutdown
CLPP Pulse by Pulse Current Limit Threshold Measured on CS 280 300 320 mV CLSD Shutdown Current Limit Threshold Measured on CS 475 600 725 mV CLDEL Current Limit Delay to Output 100mV Overdrive on CS, (Note 2) 80 ns SSI Soft-Start Current SS = 2.5V 10 13 16 µA sn37211 37211fs 3