Datasheet

9
LTC1744
1744f
SENSE (Pin 1): Reference Sense Pin. Ground selects
±1V. V
DD
selects ±1.6V. Greater than 1V and less than
1.6V applied to the SENSE pin selects an input range of
±V
SENSE
, ±1.6V is the largest valid input range.
V
CM
(Pin 2): 2.5V Output and Input Common Mode Bias.
Bypass to ground with 4.7µF ceramic chip capacitor.
GND (Pins 3, 6, 9, 12, 13, 16, 19, 21, 36, 37): ADC
Power Ground.
A
IN
+
(Pin 4): Positive Differential Analog Input.
A
IN
–
(Pin 5): Negative Differential Analog Input.
V
DD
(Pins 7, 8, 17, 18, 20): 5V Supply. Bypass to AGND
with 1µF ceramic chip capacitor.
REFLB (Pin 10): ADC Low Reference. Bypass to Pin 11 with
0.1µF ceramic chip capacitor. Do not connect to Pin␣ 14.
REFHA (Pin 11): ADC High Reference. Bypass to Pin 10 with
0.1µF ceramic chip capacitor, to Pin 14 with a 4.7µF ceramic
capacitor and to ground with 1µF ceramic capacitor.
REFLA (Pin 14): ADC Low Reference. Bypass to Pin 15 with
0.1µF ceramic chip capacitor, to Pin 11 with a 4.7µF ceramic
capacitor and to ground with 1µF ceramic capacitor.
REFHB (Pin 15): ADC High Reference. Bypass to Pin 14 with
0.1µF ceramic chip capacitor. Do not connect to Pin␣ 11.
PI FU CTIO S
UUU
MSBINV (Pin 22): MSB Inversion Control. Low inverts
the MSB, 2’s complement output format. High does not
invert the MSB, offset binary output format.
ENC (Pin 23): Encode Input. The input sample starts on
the positive edge.
ENC (Pin 24): Encode Complement Input. Conversion
starts on the negative edge. Bypass to ground with 0.1µF
ceramic for single-ended encode signal.
OE (Pin 25): Output Enable. Low enables outputs. Logic
high makes outputs Hi-Z.
CLKOUT (Pin 26): Data Valid Output. Latch data on the
rising edge of CLKOUT.
OGND (Pins 27, 38, 47): Output Driver Ground.
D0-D3 (Pins 28 to 31): Digital Outputs. D0 is the LSB.
OV
DD
(Pins 32, 43): Positive Supply for the Output Driv-
ers. Bypass to ground with 0.1µF ceramic chip capacitor.
D4-D6 (Pins 33 to 35): Digital Outputs.
D7-D10 (Pins 39 to 42): Digital Outputs.
D11-D13 (Pins 44 to 46): Digital Outputs. D13 is the MSB.
OF (Pin 48): Over/Under Flow Output. High when an over
or under flow has occurred.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
(Note 5)
FREQUENCY (MHz)
0
AMPLITUDE (dB)
–60
–30
0.5
–10
–20
–40
–50
–70
–80
–100
–110
–130
–140
816
24.99
1744 G36
–90
–120
–150
246
10 12 14
18 20 22 24
T
A
= 25°C
FREQUENCY (MHz)
0
AMPLITUDE (dB)
–60
–30
0.5
–10
–20
–40
–50
–70
–80
–100
–110
–130
–140
816
24.99
1744 G37
–90
–120
–150
246
10 12 14
18 20 22 24
T
A
= 25°C
Input = 5MHz, –25dBFS, No Dither
Input = 5MHz, –25dBFS,
Dither Applied