CS485xx Family Data Sheet

32-bit Audio Decoder DSP Family

DS734F3

Copyright 2009 Cirrus Logic, Inc.

11

CONFIDENTIAL

5.4 Power Supply Characteristics

(Measurements performed under operating conditions)

5.5 Thermal Data (48-Pin LQFP)

1. Two-layer board is specified as a 76 mm X 114 mm, 1.6 mm thick FR-4 material with 1-oz. copper covering 20 % of the top &

bottom layers.

2. Four-layer board is specified as a 76 mm X 114 mm, 1.6 mm thick FR-4 material with 1-oz. copper covering 20 % of the top &

bottom layers and 0.5-oz. copper covering 90 % of the internal power plane & ground plane layers.

3. To calculate the die temperature for a given power dissipation

T

θ

4. To calculate the case temperature for a given power dissipation

T

ψ

Parameter

Min

Typ

Max

Unit

Operational Power Supply Current:

VDDA: PLL operating

VDDIO: With most ports operating

Total Operational Power Dissipation:

Standby Power Supply Current:

VDD: Core and I/O not clocked

VDDA: PLL halted

VDDIO: All connected I/O pins 3-stated by other ICs in system

Total Standby Power Dissipation:

1. Dependent on application firmware and DSP clock speed.

-

-

-

-

-

-

-

203

8

27

480

100

1

50

348

-

-

-

-

-

-

-

mA

mA

mA

mW

μA

μA

μA

μW

Parameter

Symbol

Min

Typ

Max

Unit

Junction Temperature

-

-

125

°C

Thermal Resistance (Junction to Ambient)

Two-layer Board1

Four-layer Board2

θ

ja

-

-

63.5

54

-

-

°C / Watt

Thermal Resistance (Junction to Top of Package)

Two-layer Board3

Four-layer Board4

ψ

jt

-

-

0.70

0.64

-

-

°C / Watt