Datasheet L6981 (STMicroelectronics)
| Manufacturer | STMicroelectronics |
| Description | 38 V, 1.5 A synchronous step-down converter with low quiescent current |
| Pages / Page | 49 / 1 — L6981. Features. Applications. Maturity status link. Description. … |
| File Format / Size | PDF / 3.5 Mb |
| Document Language | English |
L6981. Features. Applications. Maturity status link. Description. DS13554. Rev 1. January 2021
Model Line for this Datasheet
Text Version of Document
L6981
Datasheet 38 V, 1.5 A synchronous step-down converter with low quiescent current
Features
• 3.5 V to 38 V operating input voltage • Output voltage from 0.85 V to VIN • 1.5 A DC output current • Internal compensation network • Two different versions: LCM for high efficiency at light-loads and LNM for noise sensitive applications • 2 μA shutdown current SO 8L • Internal soft-start • Enable • Overvoltage protection • Output voltage sequencing • Thermal protection • Synchronization to external clock for LNM devices • SO8 package
Applications
• Designed for 24 V buses industrial power systems • 24 V battery powered equipment • Decentralized intelligent nodes • Sensors and always-on applications
Maturity status link
• Low noise applications L6981
Description
The L6981 is an easy to use synchronous monolithic step-down regulator capable of delivering up to 1.5 A DC to the load. The wide input voltage range makes the device suitable for a broad range of applications. The L6981 is based on a peak current mode architecture and is packaged in an SO8 with internal compensation, thus minimizing design complexity and size. The L6981 is available both in low consumption mode (LCM) and low noise mode (LNM) versions. LCM maximizes the efficiency at light-load with controlled output voltage ripple so the device is suitable for battery-powered applications. LNM makes the switching frequency constant and minimizes the output voltage ripple for light- load operations, meeting the specification for low noise sensitive applications. The EN pin provides enable/disable functionality. The typical shutdown current is 2 µA when disabled. As soon as the EN pin is pulled up the device is enabled and the internal 1.3 ms soft-start takes place. Pulse-by-pulse current sensing on both power elements implements an effective constant current protection and thermal shutdown prevents thermal run-away.
DS13554
-
Rev 1
-
January 2021
www.st.com For further information contact your local STMicroelectronics sales office. Document Outline 1 Diagram 2 Pin configuration 3 Typical application circuit 4 Absolute maximum ratings 5 Electrical characteristics 6 Functional description 6.1 Enable 6.2 Soft-start 6.3 Undervoltage lockout 6.4 Light-load operation 6.4.1 Low consumption mode (LCM) 6.4.2 Low noise mode (LNM) 6.4.3 Efficiency for Low consumption mode and Low noise mode part number 6.4.4 Load regulation for low consumption mode and low noise mode part number 6.5 Overvoltage protection 6.5.1 Low consumption mode part number 6.5.2 Low noise mode part number 6.6 Overcurrent protection 6.7 Thermal shutdown 7 Closing the loop 7.1 GCO(s) control to output transfer function 7.2 Error amplifier compensation network 7.3 Voltage divider 8 Design of the power components 8.1 Programmable power up threshold 8.2 External synchronization (only available for Low Noise Mode) 8.3 Output voltage adjustment 8.4 Design of the power components 8.4.1 Input capacitor selection 8.4.2 Inductor selection 8.4.3 Output capacitor selection 9 Application board 10 Efficiency curves 11 Thermal dissipation 12 Package information 12.1 SO 8L package information 13 Ordering information Revision history
Datasheet 38 V, 1.5 A synchronous step-down converter with low quiescent current
Features
• 3.5 V to 38 V operating input voltage • Output voltage from 0.85 V to VIN • 1.5 A DC output current • Internal compensation network • Two different versions: LCM for high efficiency at light-loads and LNM for noise sensitive applications • 2 μA shutdown current SO 8L • Internal soft-start • Enable • Overvoltage protection • Output voltage sequencing • Thermal protection • Synchronization to external clock for LNM devices • SO8 package
Applications
• Designed for 24 V buses industrial power systems • 24 V battery powered equipment • Decentralized intelligent nodes • Sensors and always-on applications
Maturity status link
• Low noise applications L6981
Description
The L6981 is an easy to use synchronous monolithic step-down regulator capable of delivering up to 1.5 A DC to the load. The wide input voltage range makes the device suitable for a broad range of applications. The L6981 is based on a peak current mode architecture and is packaged in an SO8 with internal compensation, thus minimizing design complexity and size. The L6981 is available both in low consumption mode (LCM) and low noise mode (LNM) versions. LCM maximizes the efficiency at light-load with controlled output voltage ripple so the device is suitable for battery-powered applications. LNM makes the switching frequency constant and minimizes the output voltage ripple for light- load operations, meeting the specification for low noise sensitive applications. The EN pin provides enable/disable functionality. The typical shutdown current is 2 µA when disabled. As soon as the EN pin is pulled up the device is enabled and the internal 1.3 ms soft-start takes place. Pulse-by-pulse current sensing on both power elements implements an effective constant current protection and thermal shutdown prevents thermal run-away.
DS13554
-
Rev 1
-
January 2021
www.st.com For further information contact your local STMicroelectronics sales office. Document Outline 1 Diagram 2 Pin configuration 3 Typical application circuit 4 Absolute maximum ratings 5 Electrical characteristics 6 Functional description 6.1 Enable 6.2 Soft-start 6.3 Undervoltage lockout 6.4 Light-load operation 6.4.1 Low consumption mode (LCM) 6.4.2 Low noise mode (LNM) 6.4.3 Efficiency for Low consumption mode and Low noise mode part number 6.4.4 Load regulation for low consumption mode and low noise mode part number 6.5 Overvoltage protection 6.5.1 Low consumption mode part number 6.5.2 Low noise mode part number 6.6 Overcurrent protection 6.7 Thermal shutdown 7 Closing the loop 7.1 GCO(s) control to output transfer function 7.2 Error amplifier compensation network 7.3 Voltage divider 8 Design of the power components 8.1 Programmable power up threshold 8.2 External synchronization (only available for Low Noise Mode) 8.3 Output voltage adjustment 8.4 Design of the power components 8.4.1 Input capacitor selection 8.4.2 Inductor selection 8.4.3 Output capacitor selection 9 Application board 10 Efficiency curves 11 Thermal dissipation 12 Package information 12.1 SO 8L package information 13 Ordering information Revision history
