PRODUCT DATASHEET
AAT2610
7-Channel PMU for Digital Still Cameras
The power dissipation for the synchronous buck channel
in CCM (Continuous Conduction Mode) can be calculated
by the following equation:
Output Diode
A Schottky diode is suitable in the three non-synchronous
step-up channels for its low forward voltage and fast
recovery time. 20V rated Schottky diodes are recom-
mended for outputs less than 10V, while 30V rated
Schottky diodes are recommended for outputs greater
than 10V. Table 5 shows suggested diode part numbers.
VINBUCK
VOUTBUCK
VINBUCK
VOUTBUCK
2
PSyn-BUCK = IOUTBUCK · RDS(ON)P
·
+ RDS(ON)N · 1 -
Where:
PSyn-BUCK = Synchronous Buck Channel Power Dissipation
IOUTBUCK = Synchronous Buck Channel Output Current
VOUTBUCK = Synchronous Buck Channel Output Voltage
VINBUCK = Synchronous Buck Channel Input Voltage
RDS(ON)x = Synchronous Buck Channel PMOS or NMOS
Drain-Source On Resistance
Using SEQ for Power Sequence
Power sequence delay is designed to connect the loads
to Main channel output after its normal startup. Use the
SEQ output signal to control an external PMOSFET con-
nected between Main output and loads. The SEQ output
is high impedance lasted for 10ms when startup, then
pulled low after both the SD1 and SD2 converters com-
pleted soft-start and achieved output regulation. When
SD1 and SD2 are disabled, SEQ is also pulled low after
10ms when Main channel achieves regulation.
The power dissipation for the synchronous boost channel
in CCM can be calculated by the following equation:
VINBOOST
VOUTBOOST
VINBOOST
VOUTBOOST
2
PSyn-BOOST = IINBOOST · RDS(ON)P
·
+ RDS(ON)N · 1 -
Where:
Using SCF for Full-Load Startup
PSyn-BOOST = Synchronous Boost Channel Power
Dissipation
SCF goes high (high impedance, open drain) when over-
load protection occurs. Under normal operation, SCF
pulls low. It can be used to drive a P-channel MOSFET
switch that turns off the load of a selected supply in the
event of an overload. Or, it can remove the load until the
supply reaches regulation, effectively allowing full load
startup.
IINBOOST = Synchronous Boost Channel Input Current
VOUTBOOST = Synchronous Boost Channel Output Voltage
VINBOOST = Synchronous Boost Channel Input Voltage
RDS(ON)x = Synchronous Boost Channel PMOS or NMOS
Drain-Source On Resistance
The power dissipation for the non-synchronous boost
channel can be calculated by the following equation:
Thermal Considerations
Thermal design is an important aspect of power manage-
ment IC applications and PCB layout. The AAT2610
TQFN55-40L package can provide up to 2W of power dis-
sipation when it is properly soldered onto a printed circuit
board with thermal vias. The package has a maximum
thermal resistance of 25°C/W. The maximum power dis-
sipation in a given ambient condition can be calculated:
VINBOOST
VOUTBOOST
2
PNonsyn-BOOST = IINBOOST · RDS(ON)N · 1 -
Where:
PNonsyn-BOOST = Non-Synchronous Boost Channel Power
Dissipation
IINBOOST = Non-Synchronous Boost Channel Input
Current
VOUTBOOST = Non-Synchronous Boost Channel Output
Voltage
(TJ(MAX) - TA)
PD(MAX)
=
θJA
Where:
VINBOOST = Non-Synchronous Boost Channel Input
Voltage
RDS(ON)N = Non-Synchronous Boost Channel internal
NMOS Drain-Source On Resistance
PD(MAX) = Maximum Power Dissipation (W)
θJA = Package Thermal Resistance (°C/W)
TJ(MAX) = Maximum Device Junction Temperature (°C)
[150°C]
TA = Ambient Temperature (°C)
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ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
