L6935 STMicroelectronics, L6935 Datasheet - Page 11

• Manufacturer Part Number: L6935
• Description: High performance 3 A ULDO linear regulator
• Manufacturer: STMicroelectronics

Specifications of L6935

• Adjustable Output Voltage: 0.5 V to 3.0 V
• Excellent Load And Line Regulation: 1 % accuracy (over temperature)

Device description
5
5.1
11/20
Device description
Soft-start
L6935 implements a soft-start feature to smoothly charge the output filter avoiding high in-
rush currents to be required to the input power supply.
The soft-start process begins as soon as V
A constant current I
capacitor (C
clamps the E.A. reference, resulting in a controlled slope for the output voltage. As the
voltage on C
In this way, the soft-start process lasts for:
where C
If the device is disabled (ENABLE low) and the VBIAS is still present, the SS pin is clamped
to GND for a fixed time of about 50 µs. in order to discharge the residual charge present on
C
again.
Figure 9
Figure 9.
ENABLE
SS
Vbias
Vout
ADJ
: in this way, the device will be ready for a new SS process as ENABLE is asserted
SS
describes a typical soft-start process.
is the external capacitor [F] and T
~50µsec
SS
SS
Soft start process diagram (left) and measured (right)
) to this pin a voltage ramp is implemented; the voltage ramp internally
reaches the V
Programmed Tss
SS
= 1.0 µA is sourced through the SS pin: connecting an external
Programmed Vout
>1.1V
>0.7V
0.5V
T
REF
SS
=
value the internal clamp is released.
C
SS
⋅
V
------------- -
I
REF
SS
BIAS
SS
=
reaches UVLO and ENABLE is asserted.
is the soft-start time [sec.].
5 10
⋅
5
⋅
C
SS
F [ ]
L6935