LTC7130 PIN FUNCTIONS FREQ (B7): Oscillator Frequency Control Input. A 10µA SNS– (B2): Negative Current Sense Input. This negative current source flows out of this pin. Connecting a resistor input of the current comparator is to be connected to the between this pin and ground sets a DC voltage which in output. turn programs the oscillator frequency. Alternatively, this SNSA+ (C1): AC Current Sense Comparator Input. The (+) pin can be driven with a DC voltage to vary the frequency output to the AC current comparator is normally connected of the internal oscillator. to a DCR sensing network. When combined with the SNSD+ RUN (B6): Run Control Input. A voltage above 1.22V pin, the DCR sensing network can be skewed to increase turns on the IC. Pulling this pin below 1.1V causes the IC the AC ripple voltage by a factor of 5. to shut down. There is a 1μA pull-up current for the pin. ILIM (C2): Current Comparator Sense Voltage Limit. Apply Once the RUN pin rises above 1.22V, an additional 4.5μA a DC voltage to set the maximum current sense threshold pull-up current is added to the pin. for the current comparator. TK/SS (B5): Output Voltage Tracking and Soft-Start Input. CLKOUT (C3): Clock Output Pin. The CLKOUT signal is An internal soft-start current of 1.25μA charges the external 180° out of phase to the rising edge of the IC internal clock. soft-start capacitor connected to this pin. GND (D2, D3, D4, E1, E2, E3, F2, F3, G4, G5, G6, H4,ITH (A5): Current Control Threshold and Error Ampli- H5, H6, H7, J4, J5, J6, J7): Power Ground. Connect fier Compensation Pin. The current comparator tripping this pin closely to the (–) terminal of CV threshold is proportional with this voltage. CC and the (–) terminal of CIN. VFB (A6): Error Amplifier Feedback Input. This pin receives SW (G1, G2, G3, H1, H2, H3, J1, J2, J3): Switch Node the remotely sensed feedback voltage to set the output Connection. Connect this pin to the output filter induc- voltage through an external resistive divider connected to tor, bottom N-channel MOSFET drain and top N-channel the DIFFOUT pin or the output. MOSFET source. Voltage swing at these pins is from a DIFFOUT (A4): Output of Remote Sensing Differential Schottky diode (external) voltage drop below ground to VIN. Amplifier. Connect this pin to VFB through a resistive BOOST (F1): Boosted Top Gate Driver Supply. The (+) divider to set the desired output voltage. terminal of the bootstrap capacitor connects to this pin. DIFFN (A2): Negative Input of Remote Sensing Differen- This pin swings from a diode voltage drop below INTVCC tial Amplifier. Connect this pin close to the ground of the up to VIN + INTVCC. output load. INTVCC (D1): Internal 5.5V Regulator Output. The internal DIFFP (A3): Positive Input of Remote Sensing Differential control circuits are powered from this voltage. Decouple Amplifier. Connect this pin close to the output load. this pin to PGND with a 4.7μF low ESR tantalum or ce- SNSD+ (B1): DC Current Sense Comparator Input. The (+) ramic capacitor. output to the DC current. Comparator is normally connected to a DC current sensing network with a time constant that matches the bandwidth, L/DCR, of the inductor. 7130fb 8 For more information www.linear.com/LTC7130 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Application Related Parts .34579 Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Typical Application Related Parts