Datasheet

6
LTC1420
1420fa
TYPICAL PERFOR A CE CHARACTERISTICS
UW
I
DD
vs Clock Frequency
CLOCK FREQUENCY (MHz)
0
40
I
DD
(mA)
42
44
46
48
50
52
2468
1420 G10
10
V
REF
= 4.096V
V
REF
= 2.048V
CLOCK FREQUENCY (MHz)
0
1.0
1.2
1.4
86
1420 G11
0.8
0.6
24 10
0.4
0.2
0
I
SS
(mA)
I
SS
vs Clock Frequency
CMRR vs Input Frequency
INPUT FREQUENCY (MHz)
0.01
0
CMRR (dB)
10
30
40
50
1
90
1420 G12
20
0.1 10
60
70
80
+A
IN
(Pin 1): Positive Analog Input.
–A
IN
(Pin 2): Negative Analog Input.
V
CM
(Pin 3): 2.5V Reference Output.Optional input com-
mon mode for single supply operation. Bypass to GND
with a 1µF to 10µF ceramic.
SENSE (Pin 4): Reference Programming Pin. Ground
selects V
REF
= 4.096V. Short to V
REF
for 2.048V. Connect
SENSE to V
DD
to drive V
REF
with an external reference.
V
REF
(Pin 5): DAC Reference. Bypass to GND with a 1µF to
10µF ceramic.
GND (Pin 6): DAC Reference Ground.
V
DD
(Pin 7): Analog 5V Supply. Bypass to GND with a 1µF
to 10µF ceramic.
GND (Pin 8): Analog Power Ground.
D11 to D0 (Pins 9 to 20): Data Outputs. The output format
is two’s complement.
OGND (Pin 21): Output Logic Ground. Tie to GND.
OV
DD
(Pin 22): Positive Supply for the Output Logic.
Connect to Pin 23 for 5V logic. If not shorted to Pin 23,
bypass to GND with a 1µF ceramic.
PIN FUNCTIONS
UUU
LTC1420 Nonaveraged 4096 Point FFT
FREQUENCY (MHz)
0
–120
AMPLITUDE (dB)
–100
–80
–60
–40
–20
0
1234
1420 G13
5
f
SAMPLE
= 10Msps
f
IN
= 5.048828125MHz
SFDR = 83.2dB
SINAD = 71dB
V
IN
= 4V
P-P
±5V SUPPLIES