lan8710a Standard Microsystems Corp., lan8710a Datasheet - Page 70

• Manufacturer Part Number: lan8710a
• Description: Small Footprint Mii/rmii 10/100 Ethernet Transceiver With Hp Auto-mdix And Flexpwr Technology
• Manufacturer: Standard Microsystems Corp.

Revision 1.2 (08-10-10)
5.5.3
Configuration Strap
Configuration Strap
Pins Output Drive
SYMBOL
t
t
Power Supplies
t
purstd
purstv
t
t
t
t
odad
otaa
rstia
css
csh
All External
Pins Input
Power-On nRST & Configuration Strap Timing
This diagram illustrates the nRST reset and configuration strap timing requirements in relation to
power-on. A hardware reset (nRST assertion) is required following power-up. For proper operation,
nRST must be asserted for no less than t
not be deasserted before t
operating levels. In order for valid configuration strap values to be read at power-up, the t
timing constraints must be followed. Refer to
information.
Note: nRST deassertion must be monotonic.
Note: Device configuration straps are latched as a result of nRST assertion. Refer to
Note 5.14 20 clock cycles for 25MHz, or 40 clock cycles for 50MHz.
External power supplies at 80% to nRST deassertion
External power supplies at 80% to nRST valid
nRST input assertion time
Configuration strap pins setup to nRST deassertion
Configuration strap pins hold after nRST deassertion
Output tri-state after nRST assertion
Output drive after nRST deassertion
nRST
"Configuration Straps," on page 35
low and must not be driven as inputs.
Table 5.7 Power-On nRST & Configuration Strap Timing Values
Figure 5.3 Power-On nRST & Configuration Strap Timing
80%
DESCRIPTION
purstd
t
purstv
after all external power supplies have reached 80% of their nominal
DATASHEET
Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR
70
rstia
for details. Configuration straps must only be pulled high or
t
purstd
. The nRST pin can be asserted at any time, but must
Section 3.8.5, "Resets," on page 40
t
otaa
t
rstia
MIN
100
200
25
0
1
2
t
css
TYP
t
t
odad
csh
SMSC LAN8710A/LAN8710Ai
(Note
MAX
800
50
5.14)
for additional
Section 3.7,
css
Datasheet
®
UNITS
and t
Technology
mS
μ S
nS
nS
nS
nS
nS
csh