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L6935TR

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
May 2008 Rev 1 1/20
20
L6935
High performance 3 A ULDO linear regulator
Features
■ Up to 5 V input voltage range
■ 60 mΩ max R
DS(on)
■
35 µA shut-down current
■ 3 A maximum output current
■ Split bias and power supplies
■ Adjustable output voltage: 0.5 V to 3.0 V
■ Excellent load and line regulation: 1 %
accuracy (over temperature)
■ MLCC supported
■ Programmable soft-start
■ Short-circuit protection
■ 3.5 A overcurrent protection
■ Thermal shut-down
■ VFQFPN20 4 x 4 x 1.0 mm package
Applications
■ Motherboard
■ Mobile PC
■ Hand-held instruments
■ PCMCIA cards
■ Processors I/O
■ Chipset and RAM supply
Description
L6935 is an ultra low drop output linear regulator
operating up to 5 V input and is able to support
output current up to 3 A. Designed with an
internal low-R
DS(on)
N-channel MOSFET, it can
be used for on-board DC-DC conversions saving
in real estate, list of components and power
dissipation.
Bias input and power input are split to allow linear
conversion from buses lower than 1.2 V
minimizing power losses.
L6935 provides the application with an adjustable
voltage from 0.5 V to 3.0 V with a voltage
regulation accuracy of 1 %. soft-start is available
to program the output voltage rise-time according
to the external capacitor connected.
Enable and Power Good functions make L6935
suitable for complex systems and programmable
start-up sequencing.
The current limit at 3 A protects the system during
a short circuit. The current is sensed in the power
DMOS in order to limit the power dissipation.
Thermal shut down limits the internal temperature
at 150 °C with a hysteresis of 20 °C.
VFQFPN20
(4.0 x 4.0 x 1.0 mm)
Table 1. Device summary
Order codes Package Packing
L6935
VFQFPN20
Tu be
L6935TR Tape and reel
www.st.com
Contents L6935
2/20
Contents
1 Typical application circuit and block diagram . . . . . . . . . . . . . . . . . . . . 3
1.1 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Pins description and connection diagrams . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 Typical performances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5 Device description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1 Soft-start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.2 Power Good . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3 VIN vs VBIAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4 Protections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4.1 Over-current protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4.2 Thermal protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.1 Components selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.1.1 Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.1.2 Output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.2 VIN, VBIAS and sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7 Demonstration board description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8 VFQFPN20 mechanical data and package dimensions . . . . . . . . . . . . 18
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Typical application circuit and block diagram L6935
3/20
1 Typical application circuit and block diagram
1.1 Application circuit
Figure 1. Typical application circuit - VIN = VBIAS
Figure 2. Typical application circuit - VIN
≠ VBIAS
C
SS
L6935 Reference Schematic
V
IN
C
IN
C
OUT
R
1
R
2
V
OUT
= 0.5V to 3.0V
EN
PGOOD
L6935
VIN
SS GND PGOOD
VOUT
ADJ
EN
VBIAS
PAD
C
SS
L6935 Reference Schematic
V
IN
= 0.75V to V
BIAS
C
IN
C
OUT
R
1
R
2
V
OUT
> 0.5V (*)
PGOOD
L6935
VIN
SS GND PGOOD
VOUT
ADJ
EN
VBIAS
PAD
V
BIAS
(*) Vin may decrease until the minimum drop is reached. Conversely, Vout can rise untile the minimum drop is reached.
EN
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20

L6935TR

Mfr. #:
Buy L6935TR
Manufacturer:
STMicroelectronics
Description:
LDO Voltage Regulators High Perf 3A Uldo Reg
Lifecycle:
New from this manufacturer.
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