L7985A STMicroelectronics

L7985 2 A step-down switching regulator Datasheet - production data Applications Consumer: STB, DVD, DVD recorder, car audio, LCD TV and monitors Industrial: PLD, PLA, FPGA, chargers VFDFPN10 3 x 3 mm Networking: XDSL, modems, DC-DC modules Computer: optical storage, hard disk drive, HSOP8 exp. pad printers, audio/graphic cards LED driving Features Description 2 A DC output current The L7985/A is a step-down switching regulator 4.5 V to 38 V input voltage with a 2.5 A (minimum) current limited embedded Output voltage adjustable from 0.6 V power MOSFET, so it is able to deliver up to 2 A 250 kHz switching frequency, programmable current to the load depending on the application up to 1 MHz conditions. The input voltage can range from 4.5 V to 38 V, while the output voltage can be set Internal soft-start and enable starting from 0.6 V to V . Requiring a minimum IN Low dropout operation: 100% duty cycle set of external components, the device includes Voltage feed-forward an internal 250 kHz switching frequency oscillator that can be externally adjusted up to 1 MHz. The Zero load current operation DFN and the HSOP packages with exposed pad Overcurrent and thermal protection allow the reduction of R down to 60 C/W and thJA VFDFPN 3x3 - 10L and HSOP8 package 40 C/W respectively. Figure 1. Application circuit / L 9Q 9 9 9287 IURP 9 RW L Q9 9&& 287 *1 6<1&+ / )6: (1 )% &203 & 5 & 5 5 & 5 *1 October 2018 DocID022446 Rev 8 1/44 This is information on a product in full production. www.st.com 0 9 *1 & Contents L7985 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 .11 5.4 Overcurrent protection . 12 5.5 Enable function 14 5.6 Hysteretic thermal shutdown 14 6 Application information . 15 6.1 Input capacitor selection 15 6.2 Inductor selection . 16 6.3 Output capacitor selection 17 6.4 Compensation network . 18 6.4.1 Type III compensation network . 20 6.4.2 Type II compensation network 23 6.5 Thermal considerations 26 6.6 Layout considerations . 27 6.7 Application circuit . 29 7 Application ideas . 33 7.1 Positive buck-boost . 33 7.2 Inverting buck-boost . 35 2/44 DocID022446 Rev 8