AOZ1034DI Alpha & Omega Semiconductor Inc, AOZ1034DI Datasheet - Page 9

• Manufacturer Part Number: AOZ1034DI
• Description: IC BUCK SYNC ADJ 4A 8DFN
• Manufacturer: Alpha & Omega Semiconductor Inc
• Series: EZBuck™r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of AOZ1034DI

• Featured Product: The AOZ103x Family Synchronous Buck Regulator
• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.8 V ~ 18 V
• Current - Output: 4A
• Frequency - Switching: 500kHz
• Voltage - Input: 4.5 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-VDFN Exposed Pad
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 785-1254-2

For reliable operation and best performance, the input
capacitors must have current rating higher than I
at worst operating conditions. Ceramic capacitors are
preferred for input capacitors because of their low ESR
and high current rating. Depending on the application
circuits, other low ESR tantalum capacitor may also be
used. When selecting ceramic capacitors, X5R or X7R
type dielectric ceramic capacitors should be used for
their better temperature and voltage characteristics. Note
that the ripple current rating from capacitor manufactures
are based on certain amount of life time. Further de-
rating may be necessary in practical design.
Inductor
The inductor is used to supply constant current to output
when it is driven by a switching voltage. For given input
and output voltage, inductance and switching frequency
together decide the inductor ripple current, which is:
The peak inductor current is:
High inductance gives low inductor ripple current but
requires larger size inductor to avoid saturation. Low
ripple current reduces inductor core losses. It also
reduces RMS current through inductor and switches,
which results in less conduction loss. Usually, peak to
peak ripple current on inductor is designed to be 20%
to 30% of output current.
ΔI
I
I
CIN_RMS
Lpeak
Rev. 1.1 September 2010
L
I
O
=
(m)
Figure 2. I
---------- -
f
=
V
×
O
I
L
0.5
0.4
0.3
0.2
0.1
O
0
×
+
0
⎛
⎜
⎝
1
ΔI
------- -
CIN
2
–
L
-------- -
V
V
vs. Voltage Conversion Ratio
IN
O
⎞
⎟
⎠
0.5
m
CIN_RMS
www.aosmd.com
1
When selecting the inductor, make sure it is able to
handle the peak current without saturation even at the
highest operating temperature.
The inductor takes the highest current in a buck circuit.
The conduction loss on inductor need to be checked for
thermal and efficiency requirements.
Surface mount inductors in different shape and styles are
available from Coilcraft, Elytone and Murata. Shielded
inductors are small and radiate less EMI noise. But they
cost more than unshielded inductors. The choice
depends on EMI requirement, price and size.
Table 2 lists some inductors for typical output voltage
design.
Table 2.
Output Capacitor
The output capacitor is selected based on the DC output
voltage rating, output ripple voltage specification and
ripple current rating.
The selected output capacitor must have a higher rated
voltage specification than the maximum desired output
voltage including ripple. De-rating needs to be
considered for long term reliability.
Vout
5.0V
3.3V
1.8V
1.2V
0.8V
Unshielded, 4.7μH
LQH55DN4R7M03
Shielded, 4.7μH
LQH66SN4R7M03
Shield, 5.8μH
ET553-5R8
Un-shielded, 4.7μH
DO3316P-472MLD
Unshielded, 1.5μH
LQH55DN1R5M03
Shield, 1.5μH
LQH66SN1R5M03
Shield, 2.2μH
ET553-2R2
Un-shielded, 1.5μH
DO3316P-152MLD
Un-shielded, 1.5μH
DO1813P-152HC
L1
Manufacturer
AOZ1034
ELYTONE
ELYTONE
Page 9 of 18
MURATA
MURATA
MURATA
MURATA
Coilcraft
Coilcraft
Coilcraft