A7985A STMicroelectronics

A7985A 2 A step-down switching regulator for automotive applications Datasheet - production data Applications Dedicated to automotive applications Automotive LED driving HSOP8 exposed pad Description The A7985A is a step-down switching regulator Features with a 2.5 A (minimum) current limited embedded power MOSFET, so it is able to deliver up to 2 A AEC-Q100 qualified (see PPAP current to the load depending on the application for more details) conditions. 2 A DC output current The input voltage can range from 4.5 V to 38 V, 4.5 V to 38 V input voltage while the output voltage can be set starting from Output voltage adjustable from 0.6 V 0.6 V to V . IN 250 kHz switching frequency, programmable Requiring a minimum set of external components, up to 1 MHz the device includes an internal 250 kHz switching Internal soft-start and enable frequency oscillator that can be externally adjusted up to 1 MHz. Low dropout operation: 100% duty cycle The HSOP8 package with exposed pad allows Voltage feed-forward the reduction of R down to 40 C/W. th(JA) Zero load current operation Overcurrent and thermal protection HSOP8 package Figure 1. Application circuit / R 9 W XR W 9 & 9 & 9,19 R W 9 7 & 6<1& + (1 XW Q : &230 Y 0 February 2017 DocID023128 Rev 7 1/43 This is information on a product in full production. www.st.com 5 & 5 )6 & &L )% 5 *1 &R 9& 28Contents A7985A Contents 1 Pin settings 6 1.1 Pin connection 6 1.2 Pin description 6 2 Maximum ratings 7 3 Thermal data . 7 4 Electrical characteristics . 8 5 Functional description 10 5.1 Oscillator and synchronization 11 5.2 Soft-start 13 5.3 Error amplifier and compensation 14 5.4 Overcurrent protection . 14 5.5 Enable function 16 5.6 Hysteretic thermal shutdown 16 6 Application information . 17 6.1 Input capacitor selection 17 6.2 Inductor selection . 18 6.3 Output capacitor selection 19 6.4 Compensation network . 20 6.4.1 Type III compensation network . 22 6.4.2 Type II compensation network 25 6.5 Thermal considerations 28 6.6 Layout considerations . 29 6.7 Application circuit . 31 7 Application ideas . 35 7.1 Positive buck-boost . 35 7.2 Inverting buck-boost . 37 2/43 DocID023128 Rev 7