LTC7812 ELECTRICALCHARACTERISTICS The l denotes the specifications which apply over the specified operatingjunction temperature range, otherwise specifications are at TA = 25°C. VBIAS = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwisenoted. (Note 2) SYMBOLPARAMETERCONDITIONSMINTYPMAXUNITS VBIAS Bias Input Supply Operating Voltage 4.5 38 V Range VOUT1 Buck Regulated Output Voltage Set Point 0.8 24 V (SENSE1 Pins Common Mode Range) VOUT2 Boost Regulated Output Voltage Set Point 60 V SENSE2 Pins Common Mode Range 2.5 38 V (BOOST Converter Input Supply Voltage) VFB1 Buck Regulated Feedback Voltage (Note 4); ITH1 Voltage = 1.2V 0°C to 85°C, All Grades 0.792 0.800 0.808 V LTC7812E, LTC7812I l 0.788 0.800 0.812 V LTC7812H l 0.786 0.800 0.812 V VFB2 Boost Regulated Feedback Voltage (Note 4); ITH2 Voltage = 1.2V 0°C to 85°C, All Grades 1.183 1.200 1.214 V LTC7812E, LTC7812I l 1.181 1.200 1.218 V LTC7812H l 1.176 1.200 1.218 V IFB1,2 Feedback Current (Note 4) –2 ±50 nA Reference Voltage Line Regulation (Note 4); VIN = 4.5V to 38V 0.002 0.02 %/V Output Voltage Load Regulation (Note 4) Measured in Servo Loop; l 0.01 0.1 % DITH Voltage = 1.2V to 0.7V Measured in Servo Loop; l –0.01 –0.1 % DITH Voltage = 1.2V to 2V gm1,2 Transconductance Amplifier gm (Note 4); ITH1,2 = 1.2V; 2 mmho Sink/Source 5µA IQ Input DC Supply Current (Note 5) Pulse-Skipping or RUN1 = 5V and RUN2 = 0V or 1.5 mA Forced Continuous Mode RUN2 = 5V and RUN1 = 0V (One Channel On) VFB1 ON = 0.83V (No Load) VFB2 = 1.25V (No Load) Pulse-Skipping or RUN1,2 = 5V, 3 mA Forced Continuous Mode VFB1 = 0.83V (No Load) (Both Channels On) VFB2 = 1.25V (No Load) Sleep Mode RUN1 = 5V and RUN2 = 0V l 28 48 µA (One Channel On, Buck) VFB1 = 0.83V (No Load) Sleep Mode RUN2 = 5V and RUN1 = 0V 33 53 µA (One Channel On, Boost) VFB2 = 1.25V (No Load) Sleep Mode RUN1,2 = 5V 33 46 µA (Both Channels On) VFB1 = 0.83V (No Load) VFB2 = 1.25V (No Load) Shutdown RUN1,2 = 0V 10 20 µA UVLO Undervoltage Lockout INTVCC Ramping Up l 4.15 4.5 V INTVCC Ramping Down l 3.5 3.8 4.0 V Buck Feedback Overvoltage Protection Measured at VFB1 Relative to 7 10 13 % Regulated VFB1 SENSE1+ Pin Current ±1 µA SENSE2+ Pin Current 170 µA SENSE1– Pin Current VOUT1 < VINTVCC – 0.5V ±2 µA VOUT1 > VINTVCC + 0.5V 700 µA SENSE2– Pin Current VSENSE2+, VSENSE2– = 12V ±1 µA 7812fc For more information www.linear.com/LTC7812 3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Typical Application Related Parts