5

AT83C5127

7519A–SCR–04/05

D+

29

29

DVCC

I/O

USB Positive Data Upstream Port

This pin requires an external serial resistor of 33

Ω and a 1.5 K

up to

D-

28

28

DVCC

I/O

USB Negative Data Upstream Port

This pin requires an external serial resistor of 33

Ω

30

30

AVCC

O

USB Voltage Reference: 3.0 <

voltage is controlled by software.

XTAL1

14

14

VCC

I

Input to the on-chip inverting oscillator amplifier

To use the internal oscillator, a crystal or an external oscillator must be

connected to this pin.

XTAL2

15

15

VCC

O

Output of the on-chip inverting oscillator amplifier

To use the internal oscillator, a crystal circuit must be connected to

this pin. If an external oscillator is used, leave XTAL2 unconnected.

PLLF

26

26

AVCC

O

PLL Low Pass Filter input

Receives the RC network of the PLL low pass filter.

AVCC

27

27

PWR

Analog Supply Voltage

AVCC is used to supply the internal 3.3V analog regulator which

supplies the internal USB driver

VCC

12

12

PWR

Supply Voltage

VCC is used to supply the internal 3.3V digital regulator which

supplies the PLL, CPU core and internal I/O’s

LI

10

10

PWR

DC/DC Input

LI supplies the current for the charge pump of the DC/DC converter.

- LI tied directly to VCC : the DC/DC converter must be configured in

regulator mode.

- LI tied to VCC through an external 10µH coil : the DC/DC converter

can be configured either in regulator or in pump mode.

CVCC

9

9

PWR

Card Supply Voltage

CVCC is the ouput of internal DC/DC converter which supplies the

Smart Card Interface. It must be connected to an external decoupling

capacitor of 10 µF with the lowest ESR as this parameter influences

on the CVCC noise

DVCC

1

1

PWR

Digital Supply Voltage

DVCC is the output of the internal analog 3.3V regulator which

supplies the USB driver. This pin must be connected to an external

680nF decoupling capacitor if the USB interface is used.

CVSS

11

11

GND

DC/DC Ground

CVSS is used to sink high shunt currents from the external coil

VSS

8

8

GND

Digital Ground

VSS is used to supply the PLL, buffer ring and the digital core

AVSS

25

25

GND

Analog Ground

AVSS is used to supply the USB driver.

Table 1. Pin Description (Continued)

Port

Internal

Power

Supply ESD

I/O

Reset

Level

Alt

Reset

Config

Conf 1

Conf 2

Conf 3

Led