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SELECTING BETWEEN ROM, FASTROM AND OTP FOR A MICROCONTROLLER

3 TYPICAL MANUFACTURING LEAD TIME FOR ROM AND OTP

The complexity of all the operations needed to manufacture a component implies a certain

time period. Understanding STMicroelectronics’ MCU manufacturing cycle is important in

order to establish good relationships with customers. The numbers given here are typical and

subject to change in the future

Figure 2. Typical Fabrication Leadtime in weeks.

In order to limit lead time on ROM products, STMicroelectronics has introduced pre-diffusion

technology on selected products. This allows a two weeks reduction in total cycle time. Also

notice that MCU devices have to be ordered in specified minimum quantities for ROM version.

Figure 3. Typical Leadtime for Standard Products

5*

7

1

1

1

1

1

Transit Time**

Wafer Fabrication

Standard Wafers*

*Pre-diffused Wafers (Selected Products)

Wafer

Probing

Assembly

Final Test

Shipment

**Wafer and assembly sites are typically located in different countries.

Typical

Leadtime

for

Standard

Product

0 - 5,000 units

> 5,000 units

Min. Quantity

4

10

12

ROM

Standard

ROM

Pre-

diffused

Flash

2*

(weeks)

12

4

ROM

FAST

* Gold Standard products

> 5,000/10000 units