ADSP-BF607 datasheet(35/44 Pages) AD

35 / 44 page

Preliminary Technical Data

Rev. PrD

Page 35 of 44

March 2012

ADSP-BF606/ADSP-BF607/ADSP-BF608/ADSP-BF609

ENVIRONMENTAL CONDITIONS

To determine the junction temperature on the application

printed circuit board use:

where:

TJ = Junction temperature (°C)

TCASE = Case temperature (°C) measured by customer at top

center of package.

JT = From Table 13

PD = Power dissipation (see Total Power Dissipation on Page 34

for the method to calculate PD)

Values of

θJA are provided for package comparison and printed

circuit board design considerations.

θJA can be used for a first

order approximation of TJ by the equation:

where:

TA = Ambient temperature (°C)

Values of

θJC are provided for package comparison and printed

circuit board design considerations when an external heat sink

is required.

In Table 13, airflow measurements comply with JEDEC stan-

dards JESD51-2 and JESD51-6. The junction-to-case

measurement complies with MIL-STD-883 (Method 1012.1).

All measurements use a 2S2P JEDEC test board.

Thermal Diode

The processor incorporates thermal diode/s to monitor the die

temperature. The thermal diode is a grounded collector, PNP

Bipolar Junction Transistor (BJT). The SYS_TDA pin is con-

nected to the emitter and the SYS_TDK pin is connected to the

base of the transistor. These pins can be used by an external

temperature sensor (such as ADM 1021A or LM86 or others) to

read the die temperature of the chip.

The technique used by the external temperature sensor is to

measure the change in VBE when the thermal diode is operated

at two different currents. This is shown in the following

equation:

where:

n = multiplication factor close to 1, depending on process

variations

k = Boltzmann’s constant

T = temperature (°C)

q = charge of the electron

N = ratio of the two currents

The two currents are usually in the range of 10 micro Amperes

to 300 micro Amperes for the common temperature sensor

chips available.

Table 14 contains the thermal diode specifications using the

transistor model. Note that Measured Ideality Factor already

takes into effect variations in beta (

Β).

Table 13. Thermal Characteristics

Parameter

Condition

Typical

Unit

θJA

0 linear m/s air flow

16.7

°C/W

θJMA

1 linear m/s air flow

14.6

°C/W

θJMA

2 linear m/s air flow

13.9

°C/W

θJC

4.41

°C/W

ΨJT

0 linear m/s air flow

0.11

°C/W

ΨJT

1 linear m/s air flow

0.24

°C/W

ΨJT

2 linear m/s air flow

0.25

°C/W

TCASE

()

ΔV

------

In(N)

Table 14. Thermal Diode Parameters – Transistor Model

Symbol

Parameter

Min

Typ

Max

Unit

IFW

Forward Bias Current

TBD

μA

Emitter Current

TBD

μA

2, 3

Transistor Ideality

TBD

3, 4

Series Resistance

TBD

1 Analog Devices does not recommend operation of the thermal diode under reverse bias.

2 Not 100% tested. Specified by design characterization.

3 The ideality factor, nQ, represents the deviation from ideal diode behavior as exemplified by the diode equation: IC = IS × (e qVBE/nqkT –1), where IS = saturation current,

q = electronic charge, VBE = voltage across the diode, k = Boltzmann Constant, and T = absolute temperature (Kelvin).

4 The series resistance (RT) can be used for more accurate readings as needed.

ADSP-BF607 Datasheet(PDF) 35 Page - Analog Devices

ADSP-BF607 Datasheet(HTML) 35 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

Datasheet Download

Link URL