AN1322 datasheet(2/9 Pages) STMICROELECTRONICS

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MIGRATING AN APPLICATION FROM ST7263 REV.B TO ST7263B

3 HARDWARE CHANGES

For a summary of hardware modifications, please refer to Table 2.

3.1 PULL UP VALUE IN RESET PIN

The value of the weak pull-up resistor for the RESET pin changes from 30 k

Ω for the ST7263

Rev. B to 100 k

Ω for the ST7263B.

3.2 POWER SUPPLY

In ST7263 Rev.B, the operating power supply can lie between 3.0 V to 5.5 V without USB and

4.0 V to 5.5V with USB, while for the ST7263B, the operating supply is fixed at 4.0 V to 5.5 V

(with or without USB ).

3.3 LOW VOLTAGE DETECTOR (LVD)

The LVD generates a Reset when VDD is:

– below 4.00 V for ST7263B (4.00V for ST7263 Rev. B) when VDD is rising,

– below 3.80V for ST7263B (3.70 V for ST7263 Rev.B) when VDD is falling.

Table 2. Hardware Comparison Chart

Please refer to the corresponding datasheet for all electrical characteristics.

ST7263 Rev. B

ST7263B

RESET Pull-up Value

30K

Ω

100K

Ω

Power Supply

3.0 to 5.5V (when USB is Disabled)

4.0 to 5.5 (when USB is enabled)

4.0 to 5.5 V (with or without USB)

LVD Reset Generation

4.00 V when VDD is rising

3.70 V when VDD is falling

3.80 V when VDD is falling

AN1322 数据表(PDF) 2 Page - STMicroelectronics