Avago Technologies PEX 8605 - Manual (Page 7)

PEX8605
© PLX Technology, www.plxtech.com Page 7 of 13 2 May 2013, version 1.7
2.8 Serial EEPROM
As of this writing, a serial configuration EEPROM is not required for the PEX8605. Use of a serial
configuration EEPROM in systems designs is optional. However, we highly recommend including the serial
EEPROM circuit as a stuffing option, to allow inclusion of EEPROM-based performance enhancements
and/or errata workarounds that may become available in the future.
2.8.1 Serial EEPROM Type
If implementing serial EEPROM, use Microchip Technology, Inc. p/n 25AA128 or equivalent for
programming the PEX8605. Be sure to specify the ‘-1.8’ version of the part, which can support operation at
VCC voltage of 2.5Volts. Power the device from the VDD_IO supply, bypassed with 0.1 uF.
2.8.2 Serial EEPROM Interface
– 4 Pins
Signal Name Dual-
Row
QFN
Pkg.
Pin # TQFP
Package
Pin # Signal
Type Checked Recommendations
EE_CS# B32 73 O
YES
NO
UNKNOWN
Serial EEPROM Chip Select Output.
Connect to EEPROM CS# input. Can be left floating if
not used.
EE_DI A36 71 O
YES
NO
UNKNOWN
Serial EEPROM Data Input (Write Data)
Connect to EEPROM serial data input, SI. Can be left
floating if not used.
Note: This signal requires an external pull-up when
connecting to serial EEPROM. Recommend 4.7K – 10K
Ohms. Rise time of this signal is dependent on the
strength of the external pull-up.
EE_DO B33 75 I/PU
YES
NO
UNKNOWN
Serial EEPROM Data Output (Read Data)
Connect to EEPROM serial data output, SO. Weakly
pulled up. Should be externally pulled high to VDD25
EE_SK A38 74 O
YES
NO
UNKNOWN
Serial EEPROM Clock Output
Connect to EEPROM clock input, SCK. Can be left
floating if not used.
2.8.3 Additional EEPROM Signals
 WP#:
Tie to EEPROM VCC if not used, else jumper to GND to enable write-protect.
 HOLD#:
Tie to EEPROM VCC