Datasheet
Table 4.5 Power and Ground Signals
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| ACTIVE |
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NAME | DIRECTION | LEVEL | DESCRIPTION |
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VDD3.3 | N/A | N/A | 3.3V Supply. Provides power for USB 2.0 Transceiver, UTMI+ |
(V33) |
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| Digital, Digital I/O, and Regulators. |
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|
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|
REG_EN | Input | High | |
(REN) |
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| both of the on chip (VDDA1.8 and VDD1.8) regulators. When |
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| regulators are disabled: |
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| External 1.8V must be supplied to VDDA1.8 and VDD1.8 pins. |
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| When the regulators are disabled, VDDA1.8 may be connected |
|
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| to VDD1.8 and a bypass capacitor (0.1μF recommended) |
|
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| should be connected to each pin. |
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| The voltage at VDD3.3 must be at least 2.64V (0.8 * 3.3V) |
|
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| before voltage is applied to VDDA1.8 and VDD1.8. |
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VDD1.8 | N/A | N/A | 1.8V Digital Supply. Supplied by |
(V18) |
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| REG_EN is active. Low ESR 4.7uF minimum capacitor |
|
|
| requirement when using internal regulators. Do not connect |
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| VDD1.8 to VDDA1.8 when using internal regulators. When the |
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| regulators are disabled, VDD1.8 may be connected to VDD1.8A. |
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|
VSS | N/A | N/A | Common Ground. |
(GND) |
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VDDA1.8 | N/A | N/A | 1.8V Analog Supply. Supplied by |
(V18A) |
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| REG_EN is active. Low ESR 4.7uF minimum capacitor |
|
|
| requirement when using internal regulators. Do not connect |
|
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| VDD1.8A to VDD1.8 when using internal regulators. When the |
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| regulators are disabled, VDD1.8A may be connected to VDD1.8. |
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SMSC USB3280 | 11 | Revision 1.5 |
| DATASHEET |
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