參數(shù)資料
型號: AD9235BRUZRL7-65
廠商: Analog Devices Inc
文件頁數(shù): 9/40頁
文件大?。?/td> 0K
描述: IC ADC 12BIT SGL 65MSPS 28TSSOP
標(biāo)準(zhǔn)包裝: 1,000
位數(shù): 12
采樣率(每秒): 65M
數(shù)據(jù)接口: 并聯(lián)
轉(zhuǎn)換器數(shù)目: 3
功率耗散(最大): 300mW
電壓電源: 單電源
工作溫度: -40°C ~ 85°C
安裝類型: 表面貼裝
封裝/外殼: 28-TSSOP(0.173",4.40mm 寬)
供應(yīng)商設(shè)備封裝: 28-TSSOP
包裝: 帶卷 (TR)
輸入數(shù)目和類型: 2 個(gè)單端,單極;1 個(gè)差分,單極
Data Sheet
AD9235
Rev. D | Page 17 of 40
High speed, high resolution ADCs are sensitive to the quality of
the clock input. The degradation in SNR at a given full-scale
input frequency (fINPUT) due only to aperture jitter (tJ) can be
calculated by
SNR Degradation = 20 × log10[2π × fINPUT × tJ]
In the equation, the rms aperture jitter, tJ, represents the root-
sum square of all jitter sources, which include the clock input,
analog input signal, and ADC aperture jitter specification.
Undersampling applications are particularly sensitive to jitter.
The clock input should be treated as an analog signal in cases
where aperture jitter may affect the dynamic range of the
AD9235. Power supplies for clock drivers should be separated
from the ADC output driver supplies to avoid modulating the
clock signal with digital noise. Low jitter, crystal-controlled
oscillators make the best clock sources. If the clock is generated
from another type of source (by gating, dividing, or other
methods), it should be retimed by the original clock at the last
step.
POWER DISSIPATION AND STANDBY MODE
As shown in Figure 38, the power dissipated by the AD9235 is
proportional to its sample rate. The digital power dissipation
does not vary substantially between the three speed grades
because it is determined primarily by the strength of the digital
drivers and the load on each output bit. The maximum DRVDD
current can be calculated as
IDRVDD = VDRVDD × CLOAD × fCLK × N
where N is the number of output bits, 12 in the case of the
AD9235. This maximum current occurs when every output bit
switches on every clock cycle, i.e., a full-scale square wave at the
Nyquist frequency, fCLK/2. In practice, the DRVDD current is
established by the average number of output bits switching,
which is determined by the encode rate and the characteristics
of the analog input signal.
02461-038
SAMPLE RATE (MSPS)
60
0
10
20
30
40
50
TOTAL
POWER
(mW)
325
300
275
250
225
200
175
150
125
100
75
50
AD9235-20
AD9235-40
AD9235-65
Figure 38. Total Power vs. Sample Rate with fIN = 10 MHz
For the AD9235-20 speed grade, the digital power consumption
can represent as much as 10% of the total dissipation. Digital
power consumption can be minimized by reducing the capaci-
tive load presented to the output drivers. The data in Figure 38
was taken with a 5 pF load on each output driver.
The analog circuitry is optimally biased so that each speed
grade provides excellent performance while affording reduced
power consumption. Each speed grade dissipates a baseline
power at low sample rates that increases linearly with the clock
frequency.
By asserting the PDWN pin high, the AD9235 is placed in
standby mode. In this state, the ADC typically dissipates 1 mW
if the CLK and analog inputs are static. During standby, the
output drivers are placed in a high impedance state. Reasserting
the PDWN pin low returns the AD9235 into its normal
operational mode.
Low power dissipation in standby mode is achieved by shutting
down the reference, reference buffer, and biasing networks. The
decoupling capacitors on REFT and REFB are discharged when
entering standby mode and then must be recharged when
returning to normal operation. As a result, the wake-up time is
related to the time spent in standby mode, and shorter standby
cycles result in proportionally shorter wake-up times. With the
recommended 0.1 F and 10 F decoupling capacitors on REFT
and REFB, it takes approximately 1 sec to fully discharge the
reference buffer decoupling capacitors and 3 ms to restore full
operation.
相關(guān)PDF資料
PDF描述
AD9235BCPZRL7-65 IC ADC 12BIT SGL 65MSPS 32LFCSP
AD9238BSTZRL-40 IC ADC 12BIT DUAL 40MSPS 64LQFP
SP3249EEY-L/TR IC TXRX RS232 INTELLIGNT 24TSSOP
CXS3106A188P CONN PLUG 8POS STRGHT PIN
D6MBAU CONN RCPT MALE 6PIN BLACK/GOLD
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD9235XCP-65 制造商:Analog Devices 功能描述:12-BIT 3V 20 MSPS ADC - Bulk
AD9236 制造商:AD 制造商全稱:Analog Devices 功能描述:12-Bit, 80 MSPS, 3 V A/D Converter
AD9236BCP-80 制造商:Analog Devices 功能描述:ADC Single Pipelined 80Msps 12-bit Parallel 32-Pin LFCSP EP 制造商:Analog Devices 功能描述:IC 12BIT ADC 3V 80MSPS SMD 9236
AD9236BCP-80EB 制造商:Analog Devices 功能描述:Evaluation Board For 12-Bit, 80 MSPS, 3 V A/D Converter 制造商:Analog Devices 功能描述:EVAL BD FOR 12-BIT, 80 MSPS, 3V A/D CNVRTR - Bulk
AD9236BCPRL7-80 制造商:Analog Devices 功能描述:ADC Single Pipelined 80Msps 12-bit Parallel 32-Pin LFCSP EP T/R