Datasheet

LTC1863/LTC1867
5
18637fa
TIMING CHARACTERISTICS
Note 4: When these pin voltages are taken below GND, they will be
clamped by internal diodes. This product can handle input currents of
greater than 100mA below GND without latchup. These pins are not
clamped to V
DD
.
Note 5: V
DD
= 5V, f
SAMPLE
= 200ksps at 25°C, t
r
= t
f
= 5ns and
V
IN
– = 2.5V for bipolar mode unless otherwise specifi ed.
Note 6: Linearity, offset and gain error specifi cations apply for both
unipolar and bipolar modes. The INL and DNL are tested in bipolar mode.
Note 7: Integral nonlinearity is defi ned as the deviation of a code from a
straight line passing through the actual endpoints of the transfer curve.
The deviation is measured from the center of the quantization band.
Integral Nonlinearity vs
Output Code
Differential Nonlinearity vs
Output Code
Histogram for 4096 Conversions
4096 Points FFT Plot (f
IN
= 1kHz)
4096 Points FFT Plot (f
IN
= 1kHz,
REFCOMP = External 5V)
Crosstalk vs Input Frequency
FREQUENCY (kHz)
0
0
–20
–40
–60
–80
–100
–120
–140
75
18637 G04
25 50 100
AMPLITUDE (dB)
FREQUENCY (kHz)
0
0
–20
–40
–60
–80
–100
–120
–140
75
18637 G05
25 50 100
AMPLITUDE (dB)
ACTIVE CHANNEL INPUT FREQUENCY (kHz)
1
RESULTING AMPLITUDE ON
SELECTED CHANNEL (dB)
–80
–90
–100
–110
–120
–130
–140
10 100 1000
18637 G06
ADJACENT PAIR
NONADJACENT PAIR
SNR = 88.8dB
SINAD = 87.9dB
THD = 95dB
f
SAMPLE
= 200ksps
INTERNAL REFERENCE
SNR = 90dB
SINAD = 88.5dB
THD = 94dB
f
SAMPLE
= 200ksps
V
REF
= 0V
REFCOMP = EXT 5V
OUTPUT CODE
0
INL (LSB)
49152
18637 GO1
16384 32768 65536
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
OUTPUT CODE
0
DNL (LSB)
4915216384 32768 65536
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
18637 GO2
CODE
–4
COUNTS
4
18637 GO3
–2–3
0–1
321
2500
2000
1500
1000
500
0
1
26
276
2152
579
122
5
0
935
TYPICAL PERFORMANCE CHARACTERISTICS
(LTC1867)
Note 8: Unipolar offset is the offset voltage measured from +1/2LSB
when the output code fl ickers between 0000 0000 0000 0000 and
0000 0000 0000 0001 for LTC1867 and between 0000 0000 0000 and
0000 0000 0001 for LTC1863. Bipolar offset is the offset voltage measured
from –1/2LSB when output code fl ickers between 0000 0000 0000 0000
and 1111 1111 1111 1111 for LTC1867, and between
0000 0000 0000 and 1111 1111 1111 for LTC1863.
Note 9: Recommended operating conditions. The input range of ±2.048V
for bipolar mode is measured with respect to V
IN
– = 2.5V.
Note 10: Guaranteed by design, not subject to test.
Note 11: t
2
of 25ns maximum allows f
SCK
up to 20MHz for rising capture
with 50% duty cycle and f
SCK
up to 40MHz for falling capture (with 3ns
setup time for the receiving logic).
The l denotes the specifi cations which apply over the full operating temperature
range, otherwise specifi cations are at T
A
= 25°C. (Note 5)