Datasheet
OUT FB
R1 R1
V = V 1 + = 0.8 V 1 +
R2 R2
æ ö æ ö
´ ´
ç ÷ ç ÷
è ø è ø
FB
FB
V
0.8 V
R2 = = 160 kΩ
I 5 μA
»
OUT OUT
FB
V V
R1 = R2 1 = R2 1
V 0.8V
æ ö
æ ö
´ - ´ -
ç ÷
ç ÷
è ø
è ø
Vout
1.8V/3A
Vin
2.5V to 5.5V
PVIN
PVIN
EN
FB
C1
22mF
L1
1 Hm
C2
22mF
R1
200k
SW
TLV62090
SW
Power Good
AVIN
R2
160k
SS
R3
500k
AGND
PG
C4
10nF
VOS
DEF
CP
CN
C3
10nF
1
2
13
4
5
6
PGND PGND
7
8
9
10
11
12
3
14 15
16
TLV62090
SLVSBB9B –MARCH 2012–REVISED APRIL 2012
www.ti.com
Input and Output Capacitor Selection
For best output and input voltage filtering, low ESR ceramic capacitors are recommended. The input capacitor
minimizes input voltage ripple, suppresses input voltage spikes and provides a stable system rail for the device.
A 22 µF or larger input capacitor is recommended. The output capacitor value can range from 10 µF up to 150
µF and beyond. The recommended typical output capacitor value is 22 µF and can vary over a wide range as
outline in the output filter selection table.
Setting the Output Voltage
The output voltage is set by an external resistor divider according to the following equations:
(9)
(10)
(11)
When sizing R2, in order to achieve low quiescent current and acceptable noise sensitivity, use a minimum of 5
µA for the feedback current I
FB
. Larger currents through R2 improve noise sensitivity and output voltage
accuracy.
Layout Guideline
It is recommended to place all components as close as possible to the IC. The VOS connection is noise sensitive
and needs to be routed as short and directly to the output terminal of the inductor. The exposed thermal pad of
the package, analog ground (pin 6) and power ground (pin 14, 15) should have a single joint connection at the
exposed thermal pad of the package. This minimizes switch node jitter. The charge pump capacitor connected to
CP and CN should be placed close to the IC to minimize coupling of switching waveforms into other traces and
circuits. See the evaluation module User Guide (SLVU670) for an example of component placement, routing and
thermal design.
TYPICAL APPLICATIONS
Figure 21. 1.8 V Adjustable Version
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Product Folder Link(s): TLV62090