L4957A_06 STMICROELECTRONICS | Alldatasheet

Document overview

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Technical content

Datasheet sections

  • 1 Block diagram and typical application
  • 2 Pin description
  • 2.1 Pin connection
  • 2.2 Pin description
  • 3 Maximum ratings
  • 3.1 Absolute maximum ratings
  • 3.2 Thermal data
  • 4 Electrical characteristics
  • 5 Package mechanical data
  • 6 Revision history

Up to 5A ULDO linear regulator General features ■ 1.5V, 1.8V, 2.5V and 3.3V fixed output voltage ■ 3V to 14V input voltage range ■ 200mΩ RDS(on) typical @ tJ = 125°C ■ 0.6V max. drop-out at 2A ■ Excellent load regulation ■ 0.6mA quiescent current at any load ■ Short circuit protection ■ Thermal shutdown

Applications

■ Mother boards ■ Processor I/O & supplies ■ Low voltage memory & chip set supplies ■ Graphic & sound cards ■ Low voltage logic supplies ■ Post regulator for SMPS

Description

The L4957AD devices are Ultra Low Drop Output linear regulators with an internal N-channel MOSFET of 200mΩ particulary suitable for low voltage/low dropout applications. Operating with a input voltage from 3V to 14V they are capable to deliver up to 5A. The devices are ideal for use as one of the suppliesrequired by processor, for example they are the cost effective and efficient solution for conversion from 3.3V (rail bus) to 2.5V @ 2.5A or to 1.5V with high current rating. Fast response transient minimise the output capacitor value. A minimum of 22 µF assures the stability in all load conditions. The on-chip trimming technique offers a tighter voltage reference tolerance (with ± 2% including line and load variation) beside to ensure a controlled short circuit current. Thermal shutdown provides protection against overload conditions that creates excessive junction temperature D2PAK Order codes Part number Tube Tape and Reel L4957AD1.5 L4957AD1.5TR L4957AD1.8 L4957AD1.8TR L4957AD2.5 L4957AD2.5TR L4957AD3.3 L4957AD3.3TR

1 Block diagram and typical application

Figure 1. Block diagram Figure 2. Typical application

2 Pin description

2.1 Pin connection

Figure 3. Pin connection (top view)

2.2 Pin description

Table 1. Pin description

1 IN Unregulated input voltage; this pin must be bypassed with a capacitor larger

3 Maximum ratings

3.1 Absolute maximum ratings

3.2 Thermal data

Table 2. Absolute maximum ratings Table 3. Thermal data

4 Electrical characteristics

Table 4. Electrical Characteristcs (TJ = 25°C, VIN = 5V, unless otherwise specified)

  1. Specifications referred to T J from 0°C to +125°C.

Figure 8. Ripple rejection vs. frequency Figure 9. Output voltage vs. output Figure 10. Maximum output current vs.

6.3 IOUT(A)

5 Package mechanical data

In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a Lead-free second level interconnect . The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com

Table 5. D2PAK Mechanical data Figure 11. Package dimensions

6 Revision history

Table 6. Revision history