L5983TR STMicroelectronics, L5983TR Datasheet - Page 8

• Manufacturer Part Number: L5983TR
• Description: IC REG SW 1.5A STEPDOWN 8-VFQFPN
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of L5983TR

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 0.6 ~ 18 V
• Current - Output: 1.5A
• Frequency - Switching: 250kHz ~ 1MHz
• Voltage - Input: 2.9 ~ 18 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-VFQFN, 8-VFQFPN
• Power - Output: 1.5W
• For Use With: 497-6386 - BOARD EVAL FOR L5983
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6860-2; L5983TR

Functional description
4
8/43
Functional description
The L5983 is based on a “voltage mode”, constant frequency control. The output voltage
V
an error signal that, compared to a fixed frequency sawtooth, controls the ON and OFF time
of the power switch.
The main internal blocks are shown in the block diagram in
●
●
●
●
●
●
●
●
●
Figure 3.
OUT
A fully integrated oscillator that provides sawtooth to modulate the duty cycle and the
synchronization signal. Its switching frequency can be adjusted by an external resistor.
The voltage and frequency feed forward are implemented.
The soft-start circuitry to limit inrush current during the start-up phase
The voltage mode error amplifier
The pulse width modulator and the relative logic circuitry necessary to drive the internal
power switch
The high-side driver for embedded p-channel power MOSFET switch
The peak current limit sensing block, to handle over load and short-circuit conditions
A voltage regulator and internal reference. It supplies internal circuitry and provides a
fixed internal reference.
A voltage monitor circuitry (UVLO) that checks the input and internal voltages
A thermal shutdown block, to prevent thermal run-away
is sensed by the feedback pin (FB) compared to an internal reference (0.6 V) providing
Block diagram
Doc ID 13005 Rev 7
Figure
3. They are:
L5983