NCV70522MN(2012) Просмотр технического описания (PDF) - ON Semiconductor

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производитель

NCV70522MN
(Rev.:2012)

Micro-Stepping Motor Driver

ON Semiconductor 

NCV70522MN

PACKAGE THERMAL CHARACTERISTICS

The 522 is available in a NQFP32 package. For cooling

optimizations, the NQFP has an exposed thermal pad which

has to be soldered to the PCB ground plane. The ground

plane needs thermal vias to conduct the heat to the bottom

layer. Figure 3 gives an example for good power distribution

solutions.

For precise thermal cooling calculations the major

thermal resistances of the device are given. The thermal

media to which the power of the devices has to be given are:

• Static environmental air (via the case)

• PCB board copper area (via the exposed pad)

The thermal resistances are presented in Table 5: DC

Parameters.

The major thermal resistances of the device are the Rth

from the junction−to−ambient (Rthja) and the overall Rth

from the junction−to−exposed pad (Rthjp). In the table

below one can find the values for the Rthja and Rthjp,

simulated according to JESD−51:

The Rthja for 2S2P is simulated conform JEDEC JESD−51

as follows:

• A 4−layer printed circuit board with inner power planes

and outer (top and bottom) signal layers is used

• Board thickness is 1.46 mm (FR4 PCB material)

• The 2 signal layers: 70 mm thick copper with an area of

5500 mm2 copper and 20% conductivity

• The 2 power internal planes: 36 mm thick copper with

an area of 5500 mm2 copper and 90% conductivity

The Rthja for 1S0P is simulated conform JEDEC JESD−51

as follows:

• A 1−layer printed circuit board with only 1 layer

• Board thickness is 1.46 mm (FR4 PCB material)

• The layer has a thickness of 70 mm copper with an area

of 5500 mm2 copper and 20% conductivity

ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎNÎÎÎÎQFPÎÎÎÎ−32ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ

Figure 3. Example of NQFP−32 PCB Ground Plane Layout in Top View (Preferred Layout at Top and Bottom)

ELECTRICAL SPECIFICATION

Recommended Operation Conditions

Operating ranges define the limits for functional

operation and parametric characteristics of the device. A

mission profile (Note 5) is a substantial part of the operation

conditions, hence the Customer must contact ON

Semiconductor in order to mutually agree in writing on the

allowed missions profile(s) in the application. Note that the

functionality of the chip outside these operating ranges is not

guaranteed. Operating outside the recommended operating

ranges for extended periods of time may affect device

reliability.

Table 4. OPERATING RANGES

Symbol

Parameter

Min

Max

Unit

VBB

Analog DC supply

VDD

Logic supply output voltage

TJ

Junction temperature

+6

+30

V

4.5

5.5

V

−40

+172

°C

(Note 5)

5. A mission profile describes the application specific conditions such as, but not limited to, the cumulative operating conditions over life

time, the system power dissipation, the system’s environmental conditions, the thermal design of the customer’s system, the modes,

in which the device is operated by the customer, etc.

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