PRELIMINARY
CM3121
Application Information
Other Applications
V
output internally tracks the V
output very
TT
DDQ
closely due to the matched on-chip resistors R that tap
down from the V rail, and the low offset voltage of
The CM3121 can be used without any external resis-
tors if a V
voltage of 2.5V is required by connecting
DDQ
DDQ
the V regulator. It is recommended that the V
the SENSE_V
pin to GND.
TT
REF
DDQ
trace be connected directly to the V pin, to eliminate
TT
Also in applications where a reference voltage (V
)
REF
noise and ripple on the V line caused by current
TT
is required, a PCB trace directly from the V pin can
TT
switching
be used. The V output pin has an error relative to
TT
.
V
/2 of up to +/-25mV, which is well within most
DDQ
DDR system specs of +/-50mV. This is because the
V
CC
2.8V to 3.6V
V
DDQ
REGULATOR
CCC
V
REF
VDDQ
SENSE
VDDQ
CDDQ
EN_DDR
Enable DDR
Memory #
DDR
MEMORY
V
TT
V
V
=1.25V
REF
R
REGULATOR
=1.25V
VTT
TT
R
SENSE VTT
CTT
CPU
CORE
+ I/O
CURRENT LIMIT
OVERTEMP
LOW INPUT
FAULT
GND
Figure 4. Typical Application for the CM3121
© 2004 California Micro Devices Corp. All rights reserved.
11/12/04 430 N. McCarthy Blvd., Milpitas, CA 95035-5112
●
Tel: 408.263.3214
●
Fax: 408.263.7846
●
www.calmicro.com
9
CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
