參數(shù)資料
型號: MAX197
廠商: Maxim Integrated Products, Inc.
英文描述: Multi-Range Single +5V, 12-Bit DAS with 8+4 Bus Interface(8通道,100ksps,并行,12位A/D轉(zhuǎn)換器)
中文描述: 多量程(±10V, ±5V, +10V, +5V)、單+5V、12位數(shù)DAS,8+4總線接口
文件頁數(shù): 8/16頁
文件大?。?/td> 165K
代理商: MAX197
M
Multi-Range (±10V, ±5V, +10V, +5V ),
S ingle +5V, 12-Bit DAS with 8+4 Bus Interfac e
8
_______________________________________________________________________________________
_______________Detailed Desc ription
Converter Operation
The MAX197, a multi-range, fault-tolerant ADC, uses
successive approximation and internal input track/hold
(T/H) circuitry to convert an analog signal to a 12-bit
digital output. The parallel-output format provides easy
interface to microprocessors (μPs). Figure 3 shows the
MAX197 in its simplest operational configuration.
Analog-Input T rac k/Hold
In the internal acquisition control mode (control bit D5
set to 0), the T/H enters its tracking mode on WR’s ris-
ing edge, and enters its hold mode when the internally
timed (6 clock cycles) acquisition interval ends. A low
impedance input source, which settles in less than
1.5μs, is required to maintain conversion accuracy at
the maximum conversion rate.
In the external acquisition control mode (D5 = 1), the
T/H enters its tracking mode on the first WR rising edge
and enters its hold mode when it detects the second WR
rising edge with D5 = 0. See the External Acquisition
section.
Input Bandwidth
The ADC’s input tracking circuitry has a 5MHz small-
signal bandwidth. When using the internal acquisition
mode with an external clock frequency of 2MHz, a
100ksps throughput rate can be achieved. It is possible
to digitize high-speed transient events and measure
periodic signals with bandwidths exceeding the ADC’s
sampling rate by using undersampling techniques. To
avoid high-frequency signals being aliased into the fre-
quency band of interest, anti-alias filtering is recom-
mended (MAX274/MAX275 continuous-time filters).
Input Range and Protec tion
Figure 4 shows the equivalent input circuit. With V
REF
=
4.096V, the MAX197 can be programmed for input
ranges of ±10V, ±5V, 0V to 10V, or 0V to 5V by setting the
appropriate control bits (D3, D4) in the control byte (see
Tables 2 and 3). The full-scale input voltage depends on
the voltage at REF (Table 1). When an external reference
is applied at REFADJ , the voltage at REF is given by V
REF
= 1.6384 x V
REFADJ
(2.4V < V
REF
< 4.18V).
DGND
V
DD
REF
REFADJ
INT
CH7
CH6
CH5
CH4
CH3
CH2
CH1
CH0
AGND
28
27
26
25
4.7
μ
F
0.1
μ
F
+5V
+4.096V
OUTPUT STATUS
24
23
22
21
20
19
17
16
1
2
μ
P
CONTROL
INPUTS
3
4
5
6
7
CLK
CS
WR
RD
HBEN
SHDN
D7
D6
D5
D4
D3/D11
D2/D10
D1/D9
D0/D8
100pF
μ
P DATA BUS
15
8
9
10
11
12
13
14
ANALOG
INPUTS
MAX197
Figure 3. Operational Diagram
5.12k
8.67k
12.5k
CH_
S1
S2
S3
S4
BIPOLAR
UNIPOLAR
VOLTAGE
REFERENCE
T/H
OUT
HOLD
TRACK
TRACK
HOLD
OFF
ON
C
HOLD
S1 = BIPOLAR/UNIPOLAR SWITCH
S2 = INPUT MUX SWITCH
S3, S4 = T/H SWITCH
Figure 4. Equivalent Input Circuit
RANGE (V)
ZERO SCALE
(V) -FULL SCALE +FULL SCALE
0 to 5
0
0 to 10
0
±5
-V
REF
x 1.2207
±10
-V
REF
x 2.4414
V
REF
x 1.2207
V
REF
x 2.4414
V
REF
x 1.2207
V
REF
x 2.4414
Table 1. Full Scale and Zero Scale
相關(guān)PDF資料
PDF描述
MAX197BCWI ECONOLINE: RJ & RG - Dual Output from a Single Input Rail - 3kVDC & 4kVDC Isolation - Optional Continuous Short Circuit Protected - Custom Solutions Available - UL94V-0 Package Material - Efficiency to 84%
MAX197AENI Multi-Range (【10V, 【5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus Interface
MAX197AEWI Multi-Range (【10V, 【5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus Interface
MAX197BCNI Multi-Range (【10V, 【5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus Interface
MAX197BENI Multi-Range (【10V, 【5V, +10V, +5V), Single +5V, 12-Bit DAS with 8+4 Bus Interface
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