AOZ1036DI Alpha & Omega Semiconductor Inc, AOZ1036DI Datasheet - Page 11

• Manufacturer Part Number: AOZ1036DI
• Description: IC BUCK SYNC ADJ 5A 8DFN
• Manufacturer: Alpha & Omega Semiconductor Inc
• Series: EZBuck™r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of AOZ1036DI

• 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: 5A
• 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: 785-1255-2

The compensation capacitor C
make a zero. This zero is put somewhere close to the
dominate pole f
crossover frequency. C
The equation above can also be simplified to:
An easy-to-use application software which helps to
design and simulate the compensation loop can be found
at www.aosmd.com.
Thermal Management and Layout
Consideration
In the AOZ1036 buck regulator circuit, high pulsing
current flows through two circuit loops. The first loop
starts from the input capacitors, to the VIN pin, to the
LX pin, to the filter inductor, to the output capacitor
and load, and then return to the input capacitor through
ground. Current flows in the first loop when the high side
switch is on. The second loop starts from inductor, to the
output capacitors and load, to the low side NMOSFET.
Current flows in the second loop when the low side
NMOSFET is on.
In PCB layout, minimizing the two loops area reduces the
noise of this circuit and improves efficiency. A ground
plane is strongly recommended to connect input
capacitor, output capacitor, and PGND pin of the
AOZ1036.
In the AOZ1036 buck regulator circuit, the major power
dissipating components are the AOZ1036 and the output
inductor. The total power dissipation of converter circuit
can be measured by input power minus output power.
The power dissipation of inductor can be approximately
calculated by output current and DCR of inductor.
P
P
C
C
Rev. 1.1 September 2010
inductor_loss
total_loss
C
C
=
=
-----------------------------------
2π R
C
---------------------
O
R
×
×
C
=
1.5
R
p1
C
V
L
=
IN
×
but lower than 1/5 of selected
I
O
f
×
P1
2
I
×
IN
C
R
can is selected by:
–
inductor
V
O
C
×
and resistor R
I
O
×
1.1
C
together
www.aosmd.com
The actual junction temperature can be calculated with
power dissipation in the AOZ1036 and thermal
impedance from junction to ambient.
The maximum junction temperature of AOZ1036 is
150ºC, which limits the maximum load current capability.
Please see the thermal de-rating curves for maximum
load current of the AOZ1036 under different ambient
temperature.
The thermal performance of the AOZ1036 is strongly
affected by the PCB layout. Extra care should be taken
by users during design process to ensure that the IC will
operate under the recommended environmental
conditions.
Several layout tips are listed below for the best electric
and thermal performance.
1. The LX pins are connected to internal PFET and
2. Do not use thermal relief connection to the VIN and
3. Input capacitor should be connected to the VIN pin
4. A ground plane is preferred. If a ground plane is not
5. Make the current trace from LX pins to L to Co to the
6. Pour copper plane on all unused board area and
7. Keep sensitive signal trace far away from the LX
T
junction
NFET drains. They are low resistance thermal
conduction path and most noisy switching node.
Connected a large copper plane to LX pin to help
thermal dissipation.
the PGND pin. Pour a maximized copper area to the
PGND pin and the VIN pin to help thermal
dissipation.
and the PGND pin as close as possible.
used, separate PGND from AGND and connect them
only at one point to avoid the PGND pin noise
coupling to the AGND pin.
PGND as short as possible.
connect it to stable DC nodes, like VIN, GND or
VOUT.
pins.
=
(
P
total_loss
–
P
inductor_loss
) Θ
AOZ1036
×
Page 11 of 17
JA