XRD8799AIQ Exar Corporation, XRD8799AIQ Datasheet - Page 12

• Manufacturer Part Number: XRD8799AIQ
• Description: IC ADC 10BIT 2MSPS 44PQFP
• Manufacturer: Exar Corporation

Specifications of XRD8799AIQ

• Number Of Bits: 10
• Sampling Rate (per Second): 2M
• Data Interface: Parallel
• Number Of Converters: 8
• Power Dissipation (max): 450mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-BQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS Compliant

xr
xr
F
F
The XRD8799 includes a 8-Channel analog input
multiplexer. The relationship between the clock, the
multiplexer address, the
shown in Figure 12.
F
1.4 A
IGURE
IGURE
IGURE
DB0-DB9
Address
CLOCK
CLOCK
Clock
DATA
DATA
Old Address
WR
Sample N
t
10. R
11. A
NALOG
12. MUX A
CLKS2
t
AS
N-2 Valid
A
IN
N
ELATIONSHIP OF
NALOG
Note: t
I
NPUT
t
WR
AV
a. Continuous sampling
b. Single sampling
DD
CLKS2
Old Address
DDRESS
New Address
N-1 Valid
Sample M
I
N+1
M
N
NPUT
t
= t
CLKH2
t
AH
ULTIPLEXER
CLKH2
LOW POWER, 2 MSPS, 10-BIT, A/D CONVERTER WITH 8-CHANNEL MUX
10 pF
Control
WR
= 0
E
R Series
T
200
and the output data is
QUIVALENT
IMING
D
N
ATA TO
Old Address
N Valid
BALANCE
Sample
M+1
1 pF
4
N+1
N
C
C
Selection
LOCK
Channel
IRCUIT
8
New Address
M Valid
R MUX
200
10 pF
12
The XRD8799 has very flexible input range character-
istics. The user may set V
fixed voltages and then vary the input DC and AC lev-
els to match the VREF range. Another method is to
first design the analog input circuitry and then adjust
the reference voltages for the analog input range.
One advantage is that this approach may eliminate
the need for external gain and offset adjust circuitry
which may be required by fixed input range A/Ds.
The XRD8799's performance is optimized by using
analog input circuitry that is capable of driving the A
input. Figure 11 shows the equivalent circuit for A
F
The input/output relationship is a function of V
A system can increase total gain by reducing V
1.3 A
1.5 R
IGURE
A
V
DATA = 1024 * (A
(Internal Signal)
IN
REF
80
50
= V
A2, A1, A0
= V
NALOG
13. A
EFERENCE
MUXEN
IN
REF(+)
WR
- V
NALOG
REF(-)
I
NPUT
- V
V
S
IN
OLTAGES
REF(-)
MUX T
/V
S
REF
REF(+)
)
1 pF
t
IMING
AS
10 pF
B
t
and V
WR
t
MUXEN1
160
+
REF(-)
1/2 [ V
+ V
XRD8799
REF(-)
REF(+)
t
AH
to two
REV. 1.00
]
REF
REF
:
IN
.
.
IN