The EL7554 is a fully functional synchronous 4A buck regulator with up to 96% efficiency. The device operates from a 3V to 6V VIN input supply. Using internal CMOS power FETs, the device operates at up to 100% duty cycle with an output voltage range of 0.8V to close to VIN. Adjustable high switching frequency up to 1MHz enables the use of small components, the area occupied by the converter is less than 0.58 square inches, and there are components on one side of the PCB. The EL7554 operates in constant frequency PWM mode, enabling external synchronization. The EL7554 features soft-start and full start-up control to eliminate inrush current, allowing users to easily control the start-up of multiple converters. The EL7554 also has a ±5% voltage margin, allowing the EL7554 to be powered up and down for quick and easy verification of system card performance and reliability during manufacturing test. The junction temperature indicator conveniently monitors the silicon die temperature, saving the designer the tedious thermal characterization. The EL7554 is available in a 28 Ld HTSSOP package and operates over the -40°C to +85°C temperature range.

block diagram

Detailed Description

The EL7554 is a fully functional synchronous 6A buck regulator with up to 96% efficiency. It operates from an input supply VIN in the range of 3V to 6V. The device features internal CMOS power FETs that operate at up to 100% duty cycle, resulting in output voltages ranging from 0.8V to close to VIN. Adjustable switching frequency up to 1MHz allows the use of smaller components, which are mounted on one side of the PCB, and the entire converter occupies less than 0.58 in2 of space. EL7554 works in fixed frequency PWM mode and can realize external synchronization. Exclusive on-chip impedance-free current sensing using current mode control provides overcurrent protection and excellent step load response. The EL7554 features soft-start and full start-up control, which eliminates inrush current and allows the user to easily control the start-up of multiplexers in different configurations. The EL7554 also provides a ±5% voltage tolerance, allowing the EL7554's supply voltage to fluctuate to ensure fast and easy board performance and reliability during production testing. The device conveniently monitors the silicon temperature using a junction temperature indicator, saving designers time spent on tedious thermal characterization.

Ordering Information

steady state work

Converters generally operate in a fixed frequency continuous conduction mode. To achieve fast transient response, a peak current control method is used. The inductor current is sensed through the upper PFET. The current signal, slope compensation and compensation error signals are sent to the PWM comparator to generate the PWM signal for the internal power switch. When the upper PFET turns on, the lower NFET turns off and the input voltage charges the inductor. When the PFET is turned off, the NFET is turned on, and the energy stored in the inductor is sent to the output to maintain a constant output voltage. Therefore, the waveform of LX is usually a stable square wave (see figure below) with a peak close to VIN. Therefore, LX can be a good indicator of whether the converter is working properly.