L7980 2 A step-down switching regulator Datasheet - production data Industrial: PLD, PLA, FPGA, chargers Networking: XDSL, modems, DC-DC modules Computer: HSOP8 exposed pad VFQFPN8 3 x 3 Optical storage, hard disk drive, printers, audio/graphic cards LED driving Features Description 2 A DC output current 4.5 V to 28 V input voltage The L7980 device is a step-down switching regulator with a 2.5 A (minimum) current limited Output voltage adjustable from 0.6 V embedded Power MOSFET, so it is able to deliver 250 kHz switching frequency, programmable up to 2 A current to the load depending on the up to 1 MHz application conditions. Internal soft-start and enable The input voltage can range from 4.5 V to 28 V, Low dropout operation: 100% duty cycle while the output voltage can be set starting from Voltage feed-forward 0.6 V to V . IN Zero load current operation Requiring a minimum set of external components, the device includes an internal 250 kHz switching Overcurrent and thermal protection frequency oscillator that can be externally VFQFPN 3 x 3 - 8L and HSOP8 package adjusted up to 1 MHz. The QFN and the HSOP packages with exposed Applications pad allow reducing the R down to 60 C/W thJA Consumer: and 40 C/W respectively. STB, DVD, DVD recorder, car audio, LCD TV and monitors Figure 1. Application circuit May 2014 DocID15181 Rev 6 1/42 This is information on a product in full production. www.st.comContents L7980 Contents 1 Pin settings 4 1.1 Pin connection 4 1.2 Pin description 4 2 Maximum ratings 5 3 Thermal data . 5 4 Electrical characteristics . 6 5 Functional description . 8 5.1 Oscillator and synchronization 9 5.2 Soft-start .11 5.3 Error amplifier and compensation 12 5.4 Overcurrent protection . 12 5.5 Enable function 14 5.6 Hysteretic thermal shutdown 14 6 Application informations 15 6.1 Input capacitor selection 15 6.2 Inductor selection . 16 6.3 Output capacitor selection 17 6.4 Compensation network . 19 6.4.1 Type III compensation network . 20 6.4.2 Type II compensation network 23 6.5 Thermal considerations 27 6.6 Layout considerations . 28 6.7 Application circuit . 30 7 Application ideas . 34 7.1 Positive buck-boost . 34 7.2 Inverting buck-boost . 36 2/42 DocID15181 Rev 6