AS1364-BTDT-33-1k ams, AS1364-BTDT-33-1k Datasheet - Page 11

• Manufacturer Part Number: AS1364-BTDT-33-1k
• Description: Low Dropout Controllers - LDO
• Manufacturer: ams

Specifications of AS1364-BTDT-33-1k

• Rohs: yes
• Input Voltage Max: 5.5 V
• Output Voltage: 3.3 V
• Output Current: 1 A
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TDFN-8
• Input Voltage Min: 2 V
• Minimum Operating Temperature: - 40 C

AS1364
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
9.1 Dropout Voltage
Dropout is the input to output voltage difference, below which the linear regulator ceases to regulate. At this point, the output voltage change
follows the input voltage change. Dropout voltage may be measured at different currents and, in particular at the regulator maximum one. From
this is obtained the MOSFET maximum series resistance over temperature etc. More generally:
Dropout is probably the most important specification when the regulator is used in a battery application. The dropout performance of the
regulator defines the useful “end of life” of the battery before replacement or re-charge is required.
Figure 18. Graphical Representation of Dropout Voltage
Figure 18
V
regulated output voltage of the LDO is that obtained when there is 500mV (or greater) input-output voltage differential.
9.2 Efficiency
Low quiescent current and low input-output voltage differential are important in battery applications amongst others, as the regulator efficiency is
directly related to quiescent current and dropout voltage. Efficiency is given by:
Where:
I
www.austriamicrosystems.com
Q
IN
= Quiescent current of LDO
) measured at the point where the LDO output voltage has fallen by 100mV below the nominal, fully regulated output value. The nominal
shows the variation of V
OUT
V
as V
OUT
V
IN
IN
is varied for a certain load current. The practical value of dropout is the differential voltage (V
Efficiency =
V
V
OUT
DROPOUT
-------------------------------------- -
V
V
IN
LOAD
=

I
Dropout
Voltage
Q
I
LOAD
+
Revision 1.8

I
I
LOAD
LOAD

R

SERIES

100
V
100mV
IN
V
V
= V
%
IN
OUT
OUT(TYP)
V
IN
+ 0.5V
11 - 19
(EQ 3)
(EQ 4)
OUT
-