MC7448VU1700LD Freescale Semiconductor, MC7448VU1700LD Datasheet - Page 52

• Manufacturer Part Number: MC7448VU1700LD
• Description: IC MPU RISC 32BIT 360-FCCBGA
• Manufacturer: Freescale Semiconductor

Specifications of MC7448VU1700LD

• Processor Type: MPC74xx PowerPC 32-Bit
• Speed: 1.7GHz
• Voltage: 1.3V
• Mounting Type: Surface Mount
• Package / Case: 360-FCCBGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

System Design Information
9.7.4
The MPC7448 has a temperature diode on the microprocessor that can be used in conjunction with other
system temperature monitoring devices (such as Analog Devices, ADT7461™). These devices use the
negative temperature coefficient of a diode operated at a constant current to determine the temperature of
the microprocessor and its environment. For proper operation, the monitoring device used should
auto-calibrate the device by canceling out the V
The following are the specifications of the MPC7448 on-board temperature diode:
V
V
Operating range 2–300 μA
Diode leakage < 10 nA @ 125°C
Ideality factor over 5–150 μA at 60°C: n = 1.0275 ± 0.9%
Ideality factor is defined as the deviation from the ideal diode equation:
Another useful equation is:
Where:
The ratio of I
52
f
f
> 0.40 V
< 0.90 V
V
V
I
I
V
V
V
V
I
I
q = Charge of electron (1.6 x 10
n = Ideality factor (normally 1.0)
K = Boltzman’s constant (1.38 x 10
T = Temperature (Kelvins)
H
H
fw
s
H
L
d
f
H
L
– V
I
= Smaller diode bias current
= Saturation current
= Larger diode bias current
fw
– V
= Voltage forward biased
= Voltage at diode
= Forward current
= Diode voltage while I
= Diode voltage while I
L
= I
Temperature Diode
= 1.986 × 10
L
H
= n
s
to I
L
e
KT
__
q
is usually selected to be 10:1. The previous equation simplifies to the following:
___
nKT
qV
MPC7448 RISC Microprocessor Hardware Specifications, Rev. 4
ln
f
–4
__
– 1
I
× nT
I
L
H
L
H
is flowing
is flowing
– 1
–19
–23
C)
Joules/K)
BE
variation of each MPC7448’s internal diode.
Freescale Semiconductor