- 您現在的位置：買賣IC網 > PDF目錄372193 > SP574BA 12-Bit Sampling A/D Converters PDF資料下載
參數資料
| 型號： | SP574BA |
| 元件分類： | 串行ADC |
| 英文描述： | 12-Bit Sampling A/D Converters |
| 中文描述： | 12位采樣的A / D轉換器 |
| 文件頁數： | 7/15頁 |
| 文件大?。?/td> | 172K |
| 代理商： | SP574BA |
SP574B/674B/1674B/774B
12–Bit Sampling A/D Converters
7
Copyright 2000 Sipex Corporation
2
28
STS
VLOGIC
DGND
12/8
CS
A0
R/C
CE
THREE–STATE BUFFERS AND CONTROL
NIBBLE A
NIBBLE B
NIBBLE C
27
26
25
24
23
22
21 20
19 18
17 16
OUTPUT BITS
MSB
LSB
3
4
5
6
CLOGIC
OSCILLATOR
12–BITS
12–BITS
SAMPLE/HOLD
CDAC
LSB
MSB
TOFFSET/GAIN
REF
REF
1
+
15
+5V
7
11
VCC
VEE
9
AGND
+15V
N.C.
8
10
OUT
VIN
R2
100
R1
100K
100K
-15V
+15V
100
10V
IN
20V
IN
BIP
OFF
13
14
12
ANALOG
INPUTS
0 TO 10V
0 TO 20V
12–BIT SAR
COMP
STROBE
10μF
0.1μF
10μF
0.1μF
+
Figure 2. Unipolar Input Connections
signals between ground traces and cross digital
lines at right angles only.
Grounding Considerations
Any ground path from the analog and digital
ground should be as low resistance as possible to
accommodate the ground currents present with
this device.
The analog ground current is approximately
6mA DC while the digital ground is 3mA DC.
The analog and digital common pins should be
tied together as close to the package as possible
to guarantee best performance. The code–de-
pendent currents flow through the V
and
V
terminals and not through the analog and
digital common pins.
Power Supplies
The supply voltages for the
SPx74B
must be kept
as quiet as possible from noise pickup and also
regulated from transients or drops. Because the
part has 12–bit accuracy, voltage spikes on the
supply lines can cause several LSB deviations on
the output. Switching power supply noise can be a
problem. Careful filtering and shielding should be
employed to prevent the noise from being picked
up by the converter.
Capacitor bypass pairs are needed from each sup-
ply pin to its respective ground to filter noise and
counter the problems caused by the variations in
supply current. A 10
μ
F tantalum and a 0.1
μ
F
ceramic type in parallel between V
LOGIC
(pin 1) and
digital common (pin15), and V
analog common (pin 9) is sufficient. V
is gener-
ated internally so pin 11 may be grounded or
connected to a negative supply if the
SPx74B
is
being used to upgrade an already existing design.
CALIBRATION AND CONNECTION
PROCEDURES
Unipolar
The calibration procedure consists of adjusting the
converter’s most negative output to its ideal value for
offset adjustment, and then adjusting the most positive
output to its ideal value for gain adjustment.
Starting with offset adjustment and referring to
Figure 2
, the midpoint of the first LSB increment
should be positioned at the origin to get an output
code of all 0s. To do this, an input of +
1
LSB or
+1.22mV for the 10V range and +2.44mV for the
20V range should be applied to the
SPx74B
.
Adjust the offset potentiometer R
for code transi-
tion flickers between 0000 0000 0000 and 0000
0000 0001.
相關PDF資料 |
PDF描述 |
|---|---|
| SP574BB | 12-Bit Sampling A/D Converters |
| SP574BJ | 12-Bit Sampling A/D Converters |
| SP574BK | 12-Bit Sampling A/D Converters |
| SP574BS | 12-Bit Sampling A/D Converters |
| SP574BT | 12-Bit Sampling A/D Converters |
相關代理商/技術參數 |
參數描述 |
|---|---|
| SP574BB | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:12-Bit Sampling A/D Converters |
| SP574BJ | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:12-Bit Sampling A/D Converters |
| SP574BK | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:12-Bit Sampling A/D Converters |
| SP574BKP | 制造商:Exar Corporation 功能描述: |
| SP574BS | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:12-Bit Sampling A/D Converters |
發(fā)布緊急采購，3分鐘左右您將得到回復。