Micrel, Inc.
KSZ9021RL/RN
Pin Number
Pin Name
Type(1)
Pin Function
56
RESET_N
Ipu
Chip Reset (active low)
Hardware pin configurations are strapped-in at the de-assertion (rising edge) of
RESET_N. See “Strapping Options” section for more details.
57
LDO_O
O
On-chip 1.2V LDO Controller Output
This pin drives the input gate of a P-channel MOSFET to generate 1.2V for the
chip’s core voltages. If 1.2V is provided by the system and this pin is not used, it
can be left floating.
58
59
AVDDL_PLL
XO
P
1.2V analog VDD for PLL
O
25MHz Crystal feedback
This pin is a no connect if oscillator or external clock source is used.
Crystal / Oscillator / External Clock Input
25MHz +/-50ppm tolerance
60
XI
I
61
62
AVDDH
ISET
P
3.3V analog VDD
I/O
Set transmit output level
Connect a 4.99KΩ 1% resistor to ground on this pin.
Analog ground
63
64
AGNDH_BG
AVDDH
Gnd
P
3.3V analog VDD
E-PAD
E-PAD
Gnd
Exposed Pad on bottom of chip
Connect E-PAD to ground.
Note:
1. P = Power supply.
Gnd = Ground.
I = Input.
O = Output.
I/O = Bi-directional.
Ipu = Input with internal pull-up.
Ipu/O = Input with internal pull-up / Output.
M9999-101309-1.1
October 2009
13
MICREL [ MICREL SEMICONDUCTOR ]
