ADSP-BF607 datasheet(102/112 Pages) AD

102 / 112 page

Rev. 0

Page 102 of 112

June 2013

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

Thermal Diode

The processor incorporates a thermal diode to monitor the die

temperature. The thermal diode is a grounded collector, PNP

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

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

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

temperature sensor (such as the ADM 1021A or the 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:

nQ = multiplication factor close to 1, depending on process

variations

k = Boltzmann’s constant

T = temperature (°Kelvin)

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 69 contains the thermal diode specifications using the

transistor model. Note that Measured Ideality Factor already

takes into effect variations in beta (Β).

V

------

In(N)



Table 69. Thermal Diode Parameters—Transistor Model

Symbol

Parameter

Min

Typ

Max

Unit

IFW

Forward Bias Current

300

A

Emitter Current

300

A

2, 3

Transistor Ideality

1.006

2, 4

Series Resistance

2.8



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 × (exp(qVBE/nQkT– 1), where IS = saturation current, 

q = electrical 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) 102 Page - Analog Devices

ADSP-BF607 Datasheet(HTML) 102 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 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL