LTC2274 Linear Technology, LTC2274 Datasheet - Page 13

• Manufacturer Part Number: LTC2274
• Description: 105Msps Serial Output ADC
• Manufacturer: Linear Technology

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SENSE (Pin 38): Reference Mode Select and External
Reference Input. Tie SENSE to V
2.5V bandgap reference. An external reference of 2.5V or
1.25V may be used; both reference values will set a full
scale ADC range of 2.25V (PGA = 0).
PIN FUNCTIONS
BLOCK DIAGRAM
A
A
SENSE
V
IN
IN
CM
0.5x
+
–
DITHER SIGNAL
REFERENCE
GENERATOR
CONTROL
+
–
AND PGA
S/H
REFERENCE
2.5V
1x OR 2x
STAGE
FIRST
WITH DUTY CYCLE
CLOCK DRIVER
ADC
REFERENCE
CONTROL
ENC
SECOND
DD
STAGE
+
to select the internal
PIPELINED ADC STAGES
ENC
–
THIRD
STAGE
Figure 1. Functional Block Diagram
PGA
CONTROL LOGIC
FOURTH
STAGE
DITH
MSBINV
V
common mode. Must be bypassed to ground with a
minimum of 2.2μF . Ceramic chip capacitors are recom-
mended.
GND (Exposed Pad) (Pin 41): ADC Power Ground. The
Exposed Pad on the bottom of the package needs to be
soldered to ground.
CM
STAGE
FIFTH
(Pin 39): 1.25V Output. Optimum voltage for input
SHDN
CORRECTION
LOGIC
PAT1
SCRAMBLER/
GENERATOR
PATTERN
PAT0
16
ENCODER
8B/10B
SCRAM
FAM
20
SERIALIZER
SRR1
PLL
LTC2274
20X CLK
22743 BD
SRR0
CMLOUT
CMLOUT
SYNC
SYNC
GND
13
OV
V
DD
DD
+
–
+
–
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