Datasheet

MAX1421
12-Bit, 40Msps, 3.3V, Low-Power ADC
with Internal Reference
_______________________________________________________________________________________ 5
Note 1: Internal reference, REFIN bypassed to AGND with a combination of 0.22µF in parallel with 1nF capacitor.
Note 2: External 2.048V reference applied to REFIN.
Note 3: Internal reference disabled. V
REFIN
= 0, V
REFP
= 2.162V, V
CML
= 1.65V, and V
REFN
= 1.138V.
Note 4: IMD is measured with respect to either of the fundamental tones.
Note 5: Specifies the common-mode range of the differential input signal supplied to the MAX1421.
Note 6: V
DIFF
= V
REFP
- V
REFN
.
Note 7: Input bandwidth is measured at a 3dB level.
Note 8: V
REFIN
is internally biased to 2.048V through a 10kΩ resistor.
Note 9: Measured as the ratio of the change in mid-scale offset voltage for a ± 5% change in V
AVDD
using the internal reference.
ELECTRICAL CHARACTERISTICS (continued)
(V
AVDD
= V
DVDD
= 3.3V, AGND = DGND = 0, V
IN
= ±1.024V, differential input voltage at -0.5dB FS, internal reference,
f
CLK
= 40MHz (50% duty cycle), digital output load C
L
≈ 10pF, T
A
≥ +25°C guaranteed by production test, T
A
< +25°C guarnateed
by design and characterization. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX UNITS
Pipeline Delay (Latency) Figure 5 7
f
CLK
cycles
Aperture Delay t
AD
Figure 9 2 ns
Aperture Jitter t
AJ
Figure 9 2 ps
Data Output Delay t
OD
Figure 5 5 10 14 ns
Bus Enable Time t
BE
Figure 4 5 ns
Bus Disable Time t
BD
Figure 4 5 ns
Typical Operating Characteristics
(V
AVDD
= V
DVDD
= 3.3V, AGND = DGND = 0, V
IN
= ±1.024V, differential input voltage, f
CLK
= 40MHz (50% duty cycle), digital output
load C
L
= 10pF, T
A
= T
MIN
to T
MAX,
unless otherwise noted. Typical values are at T
A
= +25°C.)
-120
-80
-100
-40
-60
-20
0
01051520
FFT PLOT, 4096-POINT RECORD,
DIFFERENTIAL INPUT
MAX1421 toc01
ANALOG INPUT FREQUENCY (MHz)
AMPLITUDE (dB)
f
IN
= 7.54MHz
A
IN
= -0.45dB FS
HD3
HD2
-120
-80
-100
-40
-60
-20
0
01051520
FFT PLOT, 4096-POINT RECORD,
DIFFERENTIAL INPUT
MAX1421 toc02
ANALOG INPUT FREQUENCY (MHz)
AMPLITUDE (dB)
f
IN
= 19.90MHz
A
IN
= -0.50dB FS
HD2
HD3
f
IN
-120
-80
-100
-40
-60
-20
0
01051520
FFT PLOT, 4096-POINT RECORD,
DIFFERENTIAL INPUT
MAX1421 toc03
ANALOG INPUT FREQUENCY (MHz)
AMPLITUDE (dB)
f
IN
= 38.54MHz
A
IN
= -0.49dB FS
HD3
HD2