L7987LTR STMicroelectronics

L7987L 61 V, 2 A asynchronous step-down switching regulator with adjustable current limitation Datasheet - production data Description The L7987L device is a step-down monolithic switching regulator able to deliver up to 2 A DC. The output voltage adjustability ranges from 0.8 V to almost V . The embedded switchover feature IN HTSSOP16 (R = 40 C/W) on the V pin maximizes the efficiency at light TH BIAS load. The adjustable current limitation, designed to select the inductor RMS current accordingly with the nominal output current, and the high Features switching frequency capability make the size of the application compact. Pulse-by-pulse current 2 A DC output current sensing with digital frequency foldback 4.5 V to 61 V operating input voltage implements an effective constant current protection over the different application R = 300 m typ. DS,ON conditions. The peak current foldback decreases Adjustable f (250 kHz - 1.5 MHz) SW the stress of the power components in heavy Low IQ-SHD (11 A typ. from V ) short-circuit condition. The PGOOD open IN collector output can also implement output Low IQ (1 mA typ. - V 24 V - V 3.3 V) IN OUT voltage sequencing during the power-up phase. Output voltage adjustable from 0.8 V to V IN Multiple devices can be synchronized sharing the Synchronization SYNCH pin to prevent beating noise in low noise applications like sensors with A/D conversion. Adjustable soft-start time Adjustable current limitation Advanced bootstrap capacitor management for LDO operation V improves efficiency at light load BIAS PGOOD open collector output Output voltage sequencing Digital frequency foldback in short-circuit Peak current foldback in short-circuit Auto-recovery thermal shutdown Applications Designed for 24 V bus Fail safe tolerant systems Programmable logic controllers (PLCs) May 2020 DocID026362 Rev 4 1/42 This is information on a product in full production. www.st.comContents L7987L Contents 1 Application schematic and block diagram . 4 2 Pin settings 5 2.1 Pin connection 5 2.2 Pin description 6 2.3 Maximum ratings 7 2.4 Thermal data . 7 2.5 ESD protection 7 3 Electrical characteristics . 8 4 Functional description 11 4.1 Oscillator and synchronization 11 4.2 Soft-start 15 4.3 Error amplifier and light-load management . 16 4.4 Low VIN operation 17 4.5 Overcurrent protection . 17 4.6 Overtemperature protection . 19 5 Application information . 20 5.1 Input capacitor selection 20 5.2 Output capacitor selection 21 5.3 Inductor selection . 22 5.4 Compensation network . 23 5.4.1 Type II compensation network 25 5.4.2 Type III compensation network . 27 5.5 Thermal considerations 29 5.6 Layout considerations . 30 6 Demonstration board . 31 7 Application ideas . 34 7.1 Positive buck-boost . 34 2/42 DocID026362 Rev 4