參數(shù)資料
型號: HI3318
廠商: Intersil Corporation
英文描述: RELAY SSR SPST 120MA 4-DIP
中文描述: 8位,15 MSPS的,閃光的A / D轉(zhuǎn)換器
文件頁數(shù): 9/12頁
文件大?。?/td> 109K
代理商: HI3318
4-1460
1
/
4
Point Trims
The
1
/
4
,
1
/
2
and
3
/
4
points on the reference ladder are
brought out for linearity adjusting or if the user wishes to
create a nonlinear transfer function. The
1
/
4
points can be
driven by the reference drivers shown (Figure 12) or by 2-K
pots connected between V
REF
+ and V
REF
-. The
1
/
2
(mid-)
point should be set first by applying an input of 257/512 x
(V
REF
) and adjusting for an output changing from 128 to
129. Similarly the
1
/
4
and
3
/
4
points can be set with inputs of
129/512 and 385/512 x (V
REF
) and adjusting for counts of
192 to 193 and 64 to 65. (Note that the points are actually
1
/
4
,
1
/
2
and
3
/
4
of full scale +1 LSB.)
9-Bit Resolution
To obtain 9-bit resolution, two HI3318s can be wired together.
Necessary ingredients include an open-ended ladder net-
work, an overflow indicator, three-state outputs, and chip-
enable controls, all of which are available on the HI3318.
The first step for connecting a 9-bit circuit is to totem-pole
the ladder networks, as illustrated in Figure 13. Since the
absolute resistance value of each ladder may vary, external
trim of the mid-reference voltage may be required.
The overflow output of the lower device now becomes the
ninth bit. When it goes high, all counts must come from the
upper device. When it goes low, all counts must come from
the lower device. This is done simply by connecting the lower
overflow signal to the CE1 control of the lower A/D converter
and the CE2 control of the upper A/D converter. The three-
state outputs of the two devices (bits 1 through 8) are now
connected in parallel to complete the circuitry. The complete
circuit for a 9-bit A/D converter is shown in Figure 14.
Grounding/Bypassing
The analog and digital supply grounds of a system should be
kept separate and only connected at the A/D. This keeps
digital ground noise out of the analog data to be converted.
Reference drivers, input amps, reference taps, and the V
AA
supply should be bypassed at the A/D to the analog side of
the ground. See Figure 15 for a block diagram of this con-
cept. All capacitors shown should be low impedance 0.1
μ
F
ceramics and should be mounted as close to the A/D as pos-
sible. If V
AA
+ is derived from V
DD
, a small (10
resistor or
inductor and additional filtering (4.7
μ
F tantalum) may be
used to keep digital noise out of the analog system.
Input Loading
The HI3318 outputs a current pulse to the V
lN
terminal at the
start of every sample period. This is due to capacitor charg-
ing and switch feedthrough and varies with input voltage and
sampling rate. The signal source must be capable of recov-
ering from the pulse before the end of the sample period to
guarantee a valid signal for the A/D to convert. Suitable high
speed amplifiers include the HA-5033, HA-2542; and
CA3450. Figure 16 is an example of an amplifier which
recovers fast enough for sampling at 15MHz.
Output Loading
The CMOS digital output stage, although capable of driving
large loads, will reflect these loads into the local ground. It is
recommended that a local QMOS buffer such as
CD74HC541 E be used to isolate capacitive loads.
Definitions
Dynamic Performance Definitions
Fast Fourier Transform (FFT) techniques are used to evaluate
the dynamic performance of the converter. A low distortion sine
wave is applied to the input, it is sampled, and the output is
stored in RAM. The data is then transformed into the frequency
domain with a 4096 point FFT and analyzed to evaluate the
dynamic performance of the A/D. The sine wave input to the
part is -0.5dB down from full scale for all these tests.
Signal-to-Noise (SNR)
SNR is the measured RMS signal to RMS noise at a speci-
fied input and sampling frequency. The noise is the RMS
sum of all of the spectral components except the fundamen-
tal and the first five harmonics.
Signal-to-Noise + Distortion Ratio (SINAD)
SINAD is the measured RMS signal to RMS sum of all
other spectral components below the Nyquist frequency
excluding DC.
Effective Number of Bits (ENOB)
The effective number of bits (ENOB) is derived from the
SINAD data. ENOB is calculated from:
ENOB = (SINAD - 1.76 + V
CORR
)/6.02,
where:
V
CORR
= 0.5dB.
Total Harmonic Distortion (THD)
THD is the ratio of the RMS sum of the first 5 harmonic com-
ponents to the RMS value of the measured input signal.
10
3
/
4
REF
(PIN 23)
10
1
/
2
REF
(PIN 20)
10
1
/
4
REF
(PIN 10)
CW
CW
CW
V
REF
+
(PIN 22)
1K
POT
510
+10V TO +30V
3
4
11
2
1
1K
POT
1K
POT
510
7
8
5
6
10
9
+
-
+
-
+
-
NOTES:
1. All Op Amps =
3
/
4
CA324E.
2. Bypass all reference points to analog ground near A/D with 0.1
μ
F
ceramic caps.
3. Adjust V
REF+
first, then
1
/
3
,
3
/
4
and
1
/
4
points.
FIGURE 12. TYPICAL
1
/
4
POINT DRIVERS FOR ADJUSTING
LINEARITY (USE FOR MAXIMUM LINEARITY)
HI3318
相關PDF資料
PDF描述
HI3318JIB 8-Bit, 15 MSPS, Flash A/D Converter
HI3318JIP 8-Bit, 15 MSPS, Flash A/D Converter
HI5703 10-Bit, 40 MSPS A/D Converter
HI5703KCB 10-Bit, 40 MSPS A/D Converter
HI5703EVAL 10-Bit, 40 MSPS A/D Converter
相關代理商/技術(shù)參數(shù)
參數(shù)描述
HI3318JIB 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:8-Bit, 15 MSPS, Flash A/D Converter
HI3318JIP 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:8-Bit, 15 MSPS, Flash A/D Converter
HI3338 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:8-Bit, CMOS R2R D/A Converter
HI3338_04 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:8-Bit, CMOS R2R D/A Converter
HI3338KIB 功能描述:IC DAC 8BIT CMOS R-R 16-SOIC RoHS:否 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 數(shù)模轉(zhuǎn)換器 系列:- 標準包裝:2,400 系列:- 設置時間:- 位數(shù):18 數(shù)據(jù)接口:串行 轉(zhuǎn)換器數(shù)目:3 電壓電源:模擬和數(shù)字 功率耗散(最大):- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:36-TFBGA 供應商設備封裝:36-TFBGA 包裝:帶卷 (TR) 輸出數(shù)目和類型:* 采樣率(每秒):*