A5974ADTR

A5974AD Up to 2 A step-down switching regulator for automotive applications Features Qualified following the AEC-Q100 requirements (see PPAP for more details) 2 A DC output current HSOP8 - exposed pad Operating input voltage from 4 V to 36 V 3.3 V / (2%) reference voltage Description Output voltage adjustable from 1.235 V to 35 V The A5974AD is a step-down monolithic power Low dropout operation: 100% duty cycle switching regulator with a minimum switch current 500 kHz internally fixed frequency limit of 2.5 A, it is therefore able to deliver up to 2 Voltage feed-forward A DC current to the load depending on the application conditions. The output voltage can be Zero load current operation set from 1.235 V to 35 V. The high current level is Internal current limiting also achieved thanks to a HSOP8 package with Inhibit for zero current consumption exposed frame, that allows to reduce the R THJ-A down to approximately 40 C/W. The device uses Synchronization an internal P-channel DMOS transistor (with a Protection against feedback disconnection typical R of 250 m) as switching element DS(on) Thermal shutdown to minimize the size of the external components. An internal oscillator fixes the switching frequency at 500 kHz. Having a minimum input voltage of Application only 4 V, it fits automotive applications requiring Dedicated to automotive applications device operation even in cold crank conditions. Pulse-by-pulse current limit with the internal frequency modulation offers an effective constant current short-circuit protection. Figure 1. Application schematic 5 . 6) 6 4 6 / U( 4 5 6/ 6 6/5 4 62 %& . 39 2 + + /-0 ). ( %8 0 . 2 N& U& + 6 6 2 + P U& N& 5 S MALL SI GNAL PO PL E R ANE W - V April 2011 Doc ID 018762 Rev 1 1/49 www.st.com 49 03 , 34 40 40 40 40 , Contents A5974AD Contents 1 Pin settings 6 1.1 Pin connection 6 1.2 Pin description 6 2 Electrical data 7 2.1 Maximum ratings 7 2.2 Thermal data . 7 3 Electrical characteristics . 8 4 Datasheet parameters over the temperature range . 10 5 Functional description 11 5.1 Power supply and voltage reference 12 5.2 Voltage monitor 12 5.3 Oscillator and synchronization . 12 5.4 Current protection . 14 5.5 Error amplifier 15 5.6 PWM comparator and power stage . 15 5.7 Inhibit function . 17 5.8 Thermal shutdown 17 6 Additional features and protection 18 6.1 Feedback disconnection 18 6.2 Output overvoltage protection . 18 6.3 Zero load . 18 7 Closing the loop . 19 7.1 Error amplifier and compensation network 20 7.2 LC filter . 21 7.3 PWM comparator . 22 8 Application information . 24 2/49 Doc ID 018762 Rev 1