WM8310GEB/V Wolfson Microelectronics, WM8310GEB/V Datasheet - Page 13

• Manufacturer Part Number: WM8310GEB/V
• Description: POWER MANAGEMENT SUBSYSTEM, 169BGA
• Manufacturer: Wolfson Microelectronics

Specifications of WM8310GEB/V

• Supply Voltage: 7V
• No. Of Step-down Dc - Dc Converters: 4
• No. Of Ldo Regulators: 11
• Digital Ic Case Style: BGA
• No. Of Pins: 169
• No. Of Regulated Outputs: 13
• Operating Temperature Range: -40°C To
• Rohs Compliant: Yes
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Pre-Production
4
w
THERMAL CHARACTERISTICS
Thermal analysis must be performed in the intended application to prevent the WM8310 from
exceeding maximum junction temperature. Several contributing factors affect thermal performance
most notably the physical properties of the mechanical enclosure, location of the device on the PCB
in relation to surrounding components and the number of PCB layers. Connecting the GND balls
through thermal vias and into a large ground plane will aid heat extraction.
Three main heat transfer paths exist to surrounding air:
The temperature rise T
The junction temperature T
The worst case conditions are when the WM8310 is operating in a high ambient temperature, with
low supply voltage, high duty cycle and high output current. Under such conditions, it is possible that
the heat dissipated could exceed the maximum junction temperature of the device. Care must be
taken to avoid this situation. An example calculation of the junction temperature is given below.
The minimum and maximum operating junction temperatures for the WM8310 are quoted in
Section 5. The maximum junction temperature is 125°C. Therefore, the junction temperature in the
above example is within the operating limits of the WM8310.
-
-
-
-
-
-
-
-
-
-
-
-
-
Package top to air (radiation).
Package bottom to PCB (radiation).
Package leads to PCB (conduction).
P
Ө
and is therefore a measure of heat transfer from the die to surrounding air.
For WM8310, Ө
The quoted Ө
box, still air, with specific PCB stack-up and tracking rules). Note that this is not
guaranteed to reflect all typical end applications.
T
P
Ө
T
T
T
A
R
A
J
D
D
JA
JA
, is the ambient temperature.
= T
= P
is the power dissipated by the device.
= 85°C (example figure)
= 500mW (example figure)
is the thermal resistance from the junction of the die to the ambient temperature
= 45°C/W
A
D
R
+T
* Ө
is given by T
R
JA
J
= 107.5°C
is given by T
JA
= 22.5°C
JA
is based on testing to the EIA/JEDEC-51-2 test environment (ie. 1ft
= 45°C/W
R
= P
J
D
= T
* Ө
A
JA
+ T
R
PP, December 2009, Rev 3.0
WM8310
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