ADS7863A [TI]

双路、2MSPS、12 位、2+2 或 3+3 通道、同步采样 SAR ADC;
ADS7863A
型号: ADS7863A
厂家: TEXAS INSTRUMENTS    TEXAS INSTRUMENTS
描述:

双路、2MSPS、12 位、2+2 或 3+3 通道、同步采样 SAR ADC

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中文:  中文翻译
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ADS7863A  
www.ti.com.cn  
ZHCSBW2 DECEMBER 2013  
双路,2 每秒百万次采样 (MSPS)12 位,2 + 2 3 + 3 通道  
同步采样模数转换器  
查询样片: ADS7863A  
1
特性  
描述  
2
四个完全或六个伪差分输入  
ADS7863A 是一款双路,12 位,2MSPS,模数转换  
(ADC),此模数转换器具有被分成两组的四个全差  
分或六个伪差分输入通道,以实现高速、同时信号采  
集。 到采样保持 (S/H) 放大器的输入为全差分,并且  
ADC 输入保持为差分信号。 这个架构在 100kHz  
时提供值为 72dB 的出色共模抑制,这在嘈杂环境中是  
一个关键的性能特性。  
信噪比 (SNR)71dB  
总谐波失真 (THD)-81dB  
可编程和经缓冲内部 2.5V 基准  
灵活的节电特性  
可变电源范围:2.7V 5.5V  
低功耗运行:5V 时为 45mW  
工作温度范围:  
-40°C +125°C  
此器件与 ADS7861 引脚兼容,但是提供诸如可编程基  
准输出,灵活电源电压(AVDD BVDD 2.7V 至  
5.5V),每个 ADC 上具有三通道的伪差分输入复用器  
和几个节电特性。  
ADS7861 ADS8361(窄间距小外形尺寸  
(SSOP) 封装)引脚兼容  
应用范围  
此器件采用紧缩小型封装(SSOP)-24 4mm × 4mm  
四方扁平无引线(QFN)-24 封装。 此器件在 -40℃ 至  
+125℃ 的扩展工作温度范围内额定运行。  
电机控制  
多轴定位系统  
三相电源控制  
SAR  
BVDD  
AVDD  
SDOA  
SDOB  
M0  
CHA0+  
CHA0-  
Input  
MUX  
CDAC  
S/H  
CHA1+  
M1  
Comparator  
SDI  
CHA1-  
CLOCK  
CHB0+  
CS  
RD  
CHB0-  
Input  
MUX  
CDAC  
S/H  
CHB1+  
BUSY  
CHB1-  
Comparator  
CONVST  
REFIN  
BGND  
SAR  
REFOUT  
AGND  
10-Bit DAC  
2.5-V Reference  
功能方框图  
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of  
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.  
2
All trademarks are the property of their respective owners.  
PRODUCTION DATA information is current as of publication date.  
Products conform to specifications per the terms of the Texas  
Instruments standard warranty. Production processing does not  
necessarily include testing of all parameters.  
Copyright © 2013, Texas Instruments Incorporated  
English Data Sheet: SBAS610  
 
ADS7863A  
ZHCSBW2 DECEMBER 2013  
www.ti.com.cn  
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with  
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.  
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more  
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.  
ORDERING INFORMATION(1)  
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or visit the  
device product folder at www.ti.com.  
ABSOLUTE MAXIMUM RATINGS(1)  
Over operating free-air temperature range, unless otherwise noted.  
VALUE  
–0.3 to +6  
UNIT  
V
AVDD to AGND  
BVDD to BGND  
BVDD to AVDD  
Supply voltage  
–0.3 to +6  
V
1.5 × AVDD  
V
Analog and reference input voltage with respect to AGND  
Digital input voltage with respect to BGND  
AGND – 0.3 to AVDD + 0.3  
BGND – 0.3 to BVDD + 0.3  
0.3  
V
V
Ground voltage difference  
|AGND – BGND|  
V
Input current to any pin except supply pins  
Maximum virtual junction temperature, TJ  
–10 to +10  
mA  
°C  
+150  
Human body model (HBM),  
JEDEC standard 22, test method  
A114-C.01, all pins  
±4000  
±1500  
V
V
Electrostatic discharge (ESD) ratings  
Charged device model (CDM),  
JEDEC standard 22, test method  
C101, all pins  
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings  
only, and do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended  
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.  
RECOMMENDED OPERATING CONDITIONS  
Over operating free-air temperature range, unless otherwise noted.  
PARAMETER  
AVDD to AGND  
MIN  
2.7  
NOM  
MAX  
5.5  
UNIT  
V
5.0  
Supply voltage  
BVDD to BGND, low voltage levels  
BVDD to BGND, 5-V logic levels  
2.7  
3.6  
V
4.5  
5.0  
2.5  
5.5  
V
Reference input voltage on REFIN  
Analog differential input voltage  
0.5  
2.525  
+VREF  
+125  
V
(CHXX+) – (CHXX–)  
–VREF  
–40  
V
Operating ambient temperature range, TA  
°C  
THERMAL INFORMATION  
ADS7863A  
THERMAL METRIC(1)  
DBQ (SSOP)  
24 PINS  
80.9  
RGE (QFN)  
UNITS  
24 PINS  
35.0  
36.1  
12.8  
0.5  
θJA  
Junction-to-ambient thermal resistance  
θJCtop  
θJB  
Junction-to-case (top) thermal resistance  
Junction-to-board thermal resistance  
44.6  
34.2  
°C/W  
ψJT  
Junction-to-top characterization parameter  
Junction-to-board characterization parameter  
Junction-to-case (bottom) thermal resistance  
9.2  
ψJB  
33.8  
12.8  
4.1  
θJCbot  
n/a  
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.  
2
Copyright © 2013, Texas Instruments Incorporated  
ADS7863A  
www.ti.com.cn  
ZHCSBW2 DECEMBER 2013  
ELECTRICAL CHARACTERISTICS  
At TA = –40°C to +125°C, entire power-supply range, VREF = 2.5 V (internal), fCLK = 32 MHz, and tDATA = 2 MSPS, unless  
otherwise noted.  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP(1)  
MAX  
UNIT  
RESOLUTION  
Resolution  
ANALOG INPUT  
12  
Bits  
FSR  
VIN  
Full-scale differential input range  
Absolute input voltage  
(CHxx+) – (CHxx–)  
–VREF  
–0.1  
+VREF  
V
CHxx+ or CHxx+ to AGND  
CHxx+ or CHxx– to AGND  
AVDD + 0.1  
V
CIN  
Input capacitance  
2
4
pF  
pF  
nA  
dB  
CID  
Differential input capacitance  
Input leakage current  
IIL  
–1  
+1  
CMRR  
Common-mode rejection ratio  
Both ADCs, dc to 100 kHz  
72  
DC ACCURACY  
–40°C < TA < +125°C  
–40°C < TA < +85°C  
–1.25  
–1  
±0.6  
±0.5  
±0.5  
±0.5  
±0.5  
±3  
+1.25  
+1  
LSB  
LSB  
LSB  
LSB  
LSB  
μV/°C  
INL  
Integral nonlinearity  
DNL  
VOS  
Differential nonlinearity  
Input offset error  
–1  
+1  
–3  
+3  
VOS match  
–3  
+3  
dVOS/dT  
GERR  
Input offset thermal drift  
Gain error  
Referred to voltage at REFIN  
–0.5%  
–0.5%  
+0.5%  
+0.5%  
GERR match  
±0.1%  
±1  
GERR/dT  
PSRR  
Gain error thermal drift  
Power-supply rejection ratio  
Referred to voltage at REFIN  
AVDD = 5.5 V  
ppm/°C  
dB  
70  
AC ACCURACY  
SINAD  
SNR  
Signal-to-noise + distortion  
VIN = 5 VPP at 100 kHz  
VIN = 5 VPP at 100 kHz  
VIN = 5 VPP at 100 kHz  
VIN = 5 VPP at 100 kHz  
69.8  
70  
71  
71.5  
–81  
84  
dB  
dB  
dB  
dB  
Signal-to-noise ratio  
THD  
Total harmonic distortion  
Spurious-free dynamic range  
–76  
SFDR  
76  
SAMPLING DYNAMICS  
tCONV  
tACQ  
tDATA  
tA  
Conversion time per ADC  
1 MHz < fCLK 32 MHz  
1 MHz < fCLK 32 MHz  
16  
2
tCLK  
tCLK  
kSPS  
ns  
Acquisition time  
Data rate  
62.5  
2000  
6
Aperture delay  
tA match  
50  
50  
ps  
tAJIT  
fCLK  
TCLK  
Aperture jitter  
Clock frequency on CLOCK  
Clock period  
ps  
1
32  
MHz  
ns  
31.25  
1000  
INTERNAL VOLTAGE REFERENCE  
Resolution  
VREFOUT  
Reference output DAC resolution  
10  
Bits  
V
Over 20% to 100% DAC range  
0.2 VREFOUT  
VREFOUT  
2.515  
DAC = 3FFh,  
–40°C < TA < +125°C  
Reference output voltage  
2.485  
2.495  
2.500  
V
DAC = 3FFh at +25°C  
2.500  
±10  
2.505  
V
ppm/°C  
mV  
dVREFOUT/dT Reference voltage drift  
–9.76  
–4  
±2.44  
±1  
9.76  
4
DNLDAC  
INLDAC  
VOSDAC  
DAC differential nonlinearity  
DAC integral nonlinearity  
DAC offset error  
LSB  
mV  
–9.76  
–4  
±1.22  
±0.5  
±2.44  
±1  
9.76  
4
LSB  
mV  
–9.76  
–4  
9.76  
4
VREFOUT = 0.5 V  
LSB  
dB  
PSRR  
Power-supply rejection ratio  
Reference output dc current  
73  
IREFOUT  
–2  
+2  
mA  
(1) All typical values are at TA = +25°C.  
Copyright © 2013, Texas Instruments Incorporated  
3
ADS7863A  
ZHCSBW2 DECEMBER 2013  
www.ti.com.cn  
ELECTRICAL CHARACTERISTICS (continued)  
At TA = –40°C to +125°C, entire power-supply range, VREF = 2.5 V (internal), fCLK = 32 MHz, and tDATA = 2 MSPS, unless  
otherwise noted.  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP(1)  
MAX  
UNIT  
INTERNAL VOLTAGE REFERENCE (continued)  
IREFSC  
tREFON  
Reference output short-circuit current(2)  
50  
mA  
ms  
Reference output settling time  
0.5  
VOLTAGE REFERENCE INPUT  
VREF Reference input voltage range  
IREF  
0.5  
2.525  
V
Reference input current  
50  
10  
μA  
pF  
CREF  
Reference input capacitance  
DIGITAL INPUTS (Logic Family: CMOS with Schmitt-Trigger)  
VIH  
VIL  
IIN  
High-level input voltage  
Low-level input voltage  
Input current  
0.7 × BVDD  
–0.3  
BVDD + 0.3  
0.3 × BVDD  
+50  
V
V
VIN = BVDD to BGND  
–50  
nA  
pF  
CIN  
Input capacitance  
5
5
DIGITAL OUTPUTS (Logic Family: CMOS)  
VOH  
VOL  
High-level output voltage  
Low-level output voltage  
High-impedance-state output current  
Output capacitance  
BVDD = 4.5 V, IOH = –100 μA  
BVDD = 4.5 V, IOH = 100 μA  
BVDD – 0.2  
–50  
V
V
0.2  
IOZ  
+50  
nA  
pF  
pF  
COUT  
CLOAD  
Load capacitance  
30  
POWER SUPPLY  
AVDD  
BVDD  
Analog supply voltage  
AVDD to AGND  
2.7  
2.7  
5.0  
3.0  
4.5  
6.5  
1.1  
1.4  
5.5  
5.5  
V
Buffer I/O supply voltage  
BVDD to BGND  
V
AVDD = 2.7 V  
6
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mA  
mW  
mW  
AVDD = 5.0 V  
8
AVDD = 2.7 V, NAP power-down  
AVDD = 5.0 V, NAP power-down  
AVDD = 2.7 V, deep power-down  
AVDD = 5.0 V, deep power-down  
BVDD = 2.7 V, CLOAD = 10 pF  
BVDD = 3.3 V, CLOAD = 10 pF  
AVDD = 2.7 V, BVDD = 2.7 V  
AVDD = 5.0 V, BVDD = 3.3 V  
1.5  
AIDD  
Analog supply current  
2.0  
0.001  
0.001  
1.3  
0.5  
0.9  
BIDD  
Buffer I/O supply current  
Power dissipation  
1.6  
13.5  
35.5  
19.7  
45.3  
PDISS  
(2) Reference output current is not limited internally.  
PARAMETRIC MEASUREMENT INFORMATION  
EQUIVALENT INPUT CIRCUIT  
RSER = 200 W  
RSW = 50 W  
CHxx+  
CPAR = 5 pF  
CS = 2 pF  
CS = 2 pF  
CPAR = 5 pF  
CHxx-  
RSER = 200 W  
RSW = 50 W  
Figure 1. Equivalent Input Circuit  
4
Copyright © 2013, Texas Instruments Incorporated  
 
ADS7863A  
www.ti.com.cn  
ZHCSBW2 DECEMBER 2013  
TIMING CHARACTERISTICS  
Conversion 1  
tCKH  
Conversion 2  
tCKL  
13  
0
1
2
3
4
5
6
7
8
9
10  
11  
12  
14  
15  
16  
1
2
3
4
CLOCK  
t1  
t6  
CONVST  
t10  
t11  
tACQ  
tCONV  
BUSY  
t4  
t5  
t7  
RD  
t3  
DP  
t2  
A2  
SDI  
C1  
C0  
P1  
P0  
N
AN  
RP  
S4  
A1  
A0  
C1  
C0  
P1  
t12  
CS  
t8  
t9  
Serial  
0
0
0
0
D11 D10  
D9  
D8  
D8  
D7  
D7  
D6  
D6  
D5  
D4  
D4  
D3  
D2  
D2  
D1  
D0  
0
0
0
0
0
D11  
D11  
Data A  
Serial  
D11 D10 D9  
D5  
D3  
D1  
D0  
0
Data B  
Figure 2. Detailed Timing Diagram (Mode I)  
CLOCK  
Cycle 1  
5 ns  
Cycle 2  
5 ns  
10 ns  
10 ns  
CONVST  
A
B
C
NOTE: All CONVST commands that occur more than 10 ns before the cycle 1 rising edge of the external clock (region A) initiate a  
conversion on the cycle 1 rising edge. All CONVST commands that occur 5 ns after the cycle 1 rising edge or 10 ns before the cycle 2 rising  
edge (region B) initiate a conversion on the cycle 2 rising edge. All CONVST commands that occur 5 ns after the cycle 2 rising edge (region  
C) initiate a conversion on the rising edge of the next clock period.  
The CONVST pin should never be switched from low to high in the region 10 ns prior to the CLOCK rising edge and 5 ns after the rising edge  
(gray areas). If CONVST is toggled in this gray area, the conversion could begin on either the same CLOCK rising edge or the following  
edge.  
Figure 3. CONVST Timing  
Copyright © 2013, Texas Instruments Incorporated  
5
 
 
 
ADS7863A  
ZHCSBW2 DECEMBER 2013  
www.ti.com.cn  
TIMING REQUIREMENTS(1)  
Over recommended operating free-air temperature range at –40°C to +125°C, AVDD = 5 V, and BVDD = 2.7 V to 5 V, unless  
otherwise noted.  
PARAMETER  
Conversion time  
COMMENTS  
fCLOCK = 32 MHz  
MIN  
406.25  
62.5  
1
MAX  
UNIT  
ns  
tCONV  
tACQ  
fCLOCK  
tCLOCK  
tCKL  
tCKH  
t1  
Acquisition time  
fCLOCK = 32 MHz  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
See Figure 2  
ns  
CLOCK frequency  
32  
MHz  
ns  
CLOCK period  
31.25  
9.4  
9.4  
20  
1000  
CLOCK low time  
ns  
CLOCK high time  
ns  
CONVST high time  
ns  
t2  
SDI setup time to CLOCK falling edge  
SDI hold time to CLOCK falling edge  
RD high setup time to CLOCK falling edge  
RD high hold time to CLOCK falling edge  
CONVST low time  
10  
ns  
t3  
5
ns  
t4  
10  
ns  
t5  
5
ns  
t6  
1
tCLOCK  
tCLOCK  
ns  
t7  
RD low time relative to CLOCK falling edge  
CS low to SDOx valid  
1
t8  
13  
See Figure 2,  
2.7 V BVDD 3.6 V  
4
3
11  
9
ns  
ns  
CLOCK rising edge to DATA valid delay  
(MIN = minimum hold time of current data;  
MAX = maximum delay to new data valid)  
t9  
See Figure 2,  
4.5 V BVDD 5.5 V  
t10  
t11  
t12  
CONVST rising edge to BUSY high delay(2)  
CLOCK rising edge to BUSY low delay  
CS low to RD high delay  
See Figure 2  
See Figure 2  
See Figure 2  
3
3
ns  
ns  
ns  
10  
(1) All input signals are specified with tR = tF = 1.5 ns (10% to 90% of BVDD) and timed from a voltage level of (VIL + VIH) / 2.  
(2) Not applicable in auto-NAP power-down mode.  
6
Copyright © 2013, Texas Instruments Incorporated  
ADS7863A  
www.ti.com.cn  
ZHCSBW2 DECEMBER 2013  
PIN CONFIGURATIONS  
DBQ PACKAGE  
SSOP-24  
(Top View)  
RGE PACKAGE  
4-mm × 4-mm QFN-24  
(TOP VIEW)  
BGND  
CHB1+  
CHB1-  
CHB0+  
CHB0-  
CHA1+  
CHA1-  
CHA0+  
CHA0-  
1
2
3
4
5
6
7
8
9
24 BVDD  
23 SDOA  
22 SDOB  
21 BUSY  
20 CLOCK  
19 CS  
1
2
3
4
5
6
18  
17  
16  
15  
14  
13  
CHA0-  
REFIN  
CHB1+  
BGND  
BVDD  
REFOUT  
18 RD  
AGND  
AVDD  
SDOA  
SDOB  
BUSY  
17 CONVST  
16 SDI  
M1  
REFIN 10  
REFOUT 11  
AGND 12  
15 M0  
14 M1  
13 AVDD  
PIN DESCRIPTIONS  
PIN NUMBER  
NAME  
SSOP  
QFN  
4
DESCRIPTION  
Analog ground. Connect to analog ground plane.  
AGND  
AVDD  
12  
13  
1
5
Analog power supply, 2.7 V to 5.5 V. Decouple to AGND with a 1-μF ceramic capacitor.  
BGND  
17  
Buffer I/O ground. Connect to digital ground plane.  
ADC busy indicator. BUSY goes high when the inputs are in hold mode and returns to low after the  
conversion finishes.  
BUSY  
21  
13  
BVDD  
24  
9
16  
1
Buffer I/O supply, 2.7 V to 5.5 V. Decouple to BGND with a 1-μF ceramic capacitor.  
Inverting analog input channel A0  
CHA0–  
CHA0+  
CHA1–  
CHA1+  
CHB0–  
CHB0+  
CHB1–  
CHB1+  
CLOCK  
8
24  
23  
22  
21  
20  
19  
18  
12  
Noninverting analog input channel A0  
Inverting analog input channel A1  
7
6
Noninverting analog input channel A1  
Inverting analog input channel B0  
5
4
Noninverting analog input channel B0  
Inverting analog input channel B1  
3
2
Noninverting analog input channel B1  
External clock input  
20  
Conversion start. The ADC switches from sample mode into hold mode on the CONVST rising edge,  
independent of the CLOCK status. The conversion starts with the next CLOCK rising edge.  
CONVST  
17  
9
CS  
M0  
19  
15  
14  
18  
10  
11  
11  
7
Chip select. When low, the SDOx outputs are active; when high, the SDOx outputs 3-state.  
Mode pin 0. Selects between analog input channels (see Table 8).  
M1  
6
Mode pin 1. Selects between the SDOx digital outputs (see Table 8).  
RD  
10  
2
Read data. Synchronization pulse for the SDOx outputs and SDI input. RD only triggers when CS is low.  
Reference voltage input. A 470-nF ceramic capacitor (min) is required at this terminal.  
Reference voltage output. The programmable internal voltage reference output is available on this pin.  
REFIN  
REFOUT  
3
Serial data input. This pin allows the additional device features to be used but SDI can also be used in an  
ADS7861-compatible manner.  
SDI  
16  
8
Serial data output for converter A. When M1 is high, both SDOA and SDOB are active. Data are valid on  
the falling CLOCK edge.  
SDOA  
SDOB  
23  
22  
15  
14  
Serial data output for converter B. Data are valid on the falling CLOCK edge.  
Copyright © 2013, Texas Instruments Incorporated  
7
ADS7863A  
ZHCSBW2 DECEMBER 2013  
www.ti.com.cn  
TYPICAL CHARACTERISTICS  
Over the entire supply voltage range, VREF = 2.5 V (internal), fCLK = 32 MHz, and tDATA = 2 MSPS, unless otherwise noted.  
1
0.8  
1
0.75  
0.5  
Positive  
0.6  
Positive  
0.4  
0.25  
0
0.2  
0
-0.2  
-0.4  
-0.6  
-0.8  
-0.25  
-0.5  
-0.75  
-1  
Negative  
Negative  
-1  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
0.5  
0.75  
1
1.25  
1.5  
1.75  
2
Temperature (°C)  
Data Rate (MSPS)  
Figure 4. INTEGRAL NONLINEARITY vs DATA RATE  
Figure 5. INTEGRAL NONLINEARITY vs TEMPERATURE  
1
1
0.75  
0.5  
0.75  
0.5  
0.25  
0
0.25  
0
-0.25  
-0.5  
-0.75  
-1  
-0.25  
-0.5  
-0.75  
-1  
0
512 1024 1536 2048 2560 3072 3584 4096  
0
512 1024 1536 2048 2560 3072 3584 4096  
Code  
Code  
Figure 6. INTEGRAL NONLINEARITY vs CODE  
Figure 7. DIFFERENTIAL NONLINEARITY vs CODE  
1
1
0.8  
0.6  
0.75  
0.5  
Positive  
0.4  
Positive  
0.25  
0
0.2  
0
-0.2  
-0.4  
-0.6  
-0.8  
-1  
-0.25  
-0.5  
-0.75  
-1  
Negative  
Negative  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
0.5  
0.75  
1
1.25  
Data Rate (MSPS)  
Figure 8. DIFFERENTIAL NONLINEARITY vs DATA RATE  
1.5  
1.75  
2
Temperature (°C)  
Figure 9. DIFFERENTIAL NONLINEARITY vs  
TEMPERATURE  
8
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TYPICAL CHARACTERISTICS (continued)  
Over the entire supply voltage range, VREF = 2.5 V (internal), fCLK = 32 MHz, and tDATA = 2 MSPS, unless otherwise noted.  
1
2
1.5  
1
0.8  
0.6  
0.4  
Offset Match  
Offset  
0.5  
0
0.2  
Offset Match  
0
-0.2  
-0.4  
-0.6  
-0.8  
-0.5  
-1  
Offset  
-1.5  
-2  
-1  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
Temperature (°C)  
2.7  
3
3.3  
3.6  
3.9  
4.2  
4.5  
4.8  
5.1  
5.5  
AVDD (V)  
Figure 10. OFFSET ERROR AND OFFSET MATCH  
vs ANALOG SUPPLY VOLTAGE  
Figure 11. OFFSET ERROR AND OFFSET MATCH  
vs TEMPERATURE  
0.1  
0.05  
0
0.2  
0.15  
0.1  
Gain Match  
Gain Match  
Gain  
0.05  
0
Gain  
-0.05  
-0.1  
-0.15  
-0.2  
-0.05  
-0.1  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
2.7  
3
3.3  
3.6  
3.9  
4.2  
4.5  
4.8  
5.1  
5.5  
Temperature (°C)  
AVDD (V)  
Figure 12. GAIN ERROR AND GAIN MATCH  
vs ANALOG SUPPLY VOLTAGE  
Figure 13. GAIN ERROR AND GAIN MATCH  
vs TEMPERATURE  
74  
73.5  
73  
74  
73.5  
73  
72.5  
72  
72.5  
72  
71.5  
71  
71.5  
71  
70.5  
70.5  
70  
70  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
2.7  
3
3.3  
3.6  
3.9  
4.2  
4.5  
4.8  
5.1  
5.5  
Temperature (°C)  
AVDD (V)  
Figure 14. COMMON-MODE REJECTION RATIO  
vs ANALOG SUPPLY VOLTAGE  
Figure 15. COMMON-MODE REJECTION RATIO  
vs TEMPERATURE  
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TYPICAL CHARACTERISTICS (continued)  
Over the entire supply voltage range, VREF = 2.5 V (internal), fCLK = 32 MHz, and tDATA = 2 MSPS, unless otherwise noted.  
0
0
-20  
-20  
-40  
-40  
-60  
-60  
-80  
-80  
-100  
-120  
-140  
-100  
-120  
-140  
0
200k  
400k  
600k  
800k  
1M  
0
100  
200  
300  
400  
500  
600  
700 750  
Frequency (Hz)  
Frequency (kHz)  
Figure 16. FREQUENCY SPECTRUM  
(4096-Point FFT; fIN = 100 kHz)  
Figure 17. FREQUENCY SPECTRUM  
(4096-Point FFT; fIN = 100 kHz, fSAMPLE = 1.5 MSPS)  
74  
73  
72  
71  
70  
69  
73  
72.5  
72  
AVDD = 5 V  
AVDD = 5 V  
AVDD = 2.7 V  
71.5  
71  
AVDD = 2.7 V  
70.5  
68  
70  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
20  
40  
60  
80  
100 120 140 160 180 200  
fIN (kHz)  
Temperature (°C)  
Figure 18. SIGNAL-TO-NOISE RATIO AND DISTORTION  
vs INPUT SIGNAL FREQUENCY  
Figure 19. SIGNAL-TO-NOISE RATIO AND DISTORTION  
vs TEMPERATURE  
74  
73  
73  
72  
71  
70  
69  
68  
72.5  
AVDD = 5 V  
AVDD = 5 V  
72  
AVDD = 2.7 V  
AVDD = 2.7 V  
71.5  
71  
70.5  
70  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
20  
40  
60  
80  
100 120 140 160 180 200  
fIN (kHz)  
Temperature (°C)  
Figure 20. SIGNAL-TO-NOISE RATIO  
vs INPUT SIGNAL FREQUENCY  
Figure 21. SIGNAL-TO-NOISE RATIO vs TEMPERATURE  
10  
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TYPICAL CHARACTERISTICS (continued)  
Over the entire supply voltage range, VREF = 2.5 V (internal), fCLK = 32 MHz, and tDATA = 2 MSPS, unless otherwise noted.  
-76  
-78  
-80  
-82  
-84  
-86  
-88  
-90  
-78  
-80  
-82  
-84  
-86  
-88  
-90  
AVDD = 5 V  
AVDD = 2.7 V  
AVDD = 2.7 V  
AVDD = 5 V  
-92  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
20  
40  
60  
80  
100 120 140 160 180 200  
fIN (kHz)  
Temperature (°C)  
Figure 22. TOTAL HARMONIC DISTORTION  
vs INPUT SIGNAL FREQUENCY  
Figure 23. TOTAL HARMONIC DISTORTION  
vs TEMPERATURE  
92  
90  
88  
86  
84  
82  
80  
78  
90  
88  
86  
84  
82  
80  
AVDD = 2.7 V  
AVDD = 5 V  
AVDD = 5 V  
AVDD = 2.7 V  
76  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
20  
40  
60  
80  
100 120 140 160 180 200  
fIN (kHz)  
Temperature (°C)  
Figure 24. SPURIOUS-FREE DYNAMIC RANGE  
vs INPUT SIGNAL FREQUENCY  
Figure 25. SPURIOUS-FREE DYNAMIC RANGE  
vs TEMPERATURE  
8
7
6
5
4
3
2
1
0
1
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
AVDD = 5 V  
BVDD = 3.3 V  
AVDD = 2.7 V  
BVDD = 2.7 V  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
Temperature (°C)  
Temperature (°C)  
Figure 26. ANALOG SUPPLY CURRENT vs TEMPERATURE  
Figure 27. DIGITAL SUPPLY CURRENT vs TEMPERATURE  
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TYPICAL CHARACTERISTICS (continued)  
Over the entire supply voltage range, VREF = 2.5 V (internal), fCLK = 32 MHz, and tDATA = 2 MSPS, unless otherwise noted.  
6
5
4
3
2
1
1.4  
1.2  
1
AVDD = 5 V  
Reference ON  
AVDD = 2.7 V  
0.8  
0.6  
0.4  
0.2  
0
Reference OFF  
0
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
Temperature (°C)  
0
500  
1000  
1500  
2000  
Data Rate (kSPS)  
Figure 28. ANALOG SUPPLY CURRENT vs DATA RATE  
(Auto-NAP Mode)  
Figure 29. ANALOG SUPPLY CURRENT vs TEMPERATURE  
(Auto-NAP Mode)  
1400  
2.505  
2.504  
2.503  
2.502  
2.501  
2.5  
1200  
1000  
800  
600  
400  
200  
0
Clock ON  
2.499  
2.498  
2.497  
2.496  
2.495  
Clock OFF  
40  
-40 -25 -10  
5
20 35 50 65 80 95 110 125  
0
10  
20  
30  
50  
60  
70  
Temperature (°C)  
Data Rate (kSPS)  
Figure 30. ANALOG SUPPLY CURRENT vs DATA RATE  
(Deep Power-Down Mode)  
Figure 31. REFERENCE OUTPUT VOLTAGE  
vs TEMPERATURE  
12  
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APPLICATIONS INFORMATION  
GENERAL DESCRIPTION  
The ADS7863A includes two 12-bit, analog-to-digital converters (ADCs) that operate based on the successive-  
approximation register (SAR) principle. The ADCs sample and convert simultaneously. Conversion time can be  
as low as 406.25 ns. Adding the 62.5-ns acquisition time and an additional clock cycle for setup and hold time  
requirements and skew results in a maximum conversion rate of 2 MSPS.  
Each ADC has a fully-differential, 2:1 multiplexer front-end. In many common applications, all negative input  
signals remain at the same constant voltage (for example, 2.5 V). In this type of application, the multiplexer can  
be used in a pseudo-differential 3:1 mode, where CHx0– functions as a common-mode input and the remaining  
three inputs (CHx0+, CHx1–, and CHx1+) operate as separate inputs referred to the common-mode input.  
The ADS7863A also includes a 2.5-V internal reference. The reference drives a 10-bit digital-to-analog converter  
(DAC), allowing the voltage at the REFOUT pin to be adjusted via the serial interface in 2.44-mV steps. A low-  
noise operational amplifier with unity gain buffers the DAC output voltage and drives the REFOUT pin.  
The ADS7863A offers a serial interface that is compatible with the ADS7861. However, instead of the A0 pin of  
the ADS7861 controlling channel selection, the ADS7863A offers a serial data input (SDI) pin that supports  
additional functions described in the Digital section (see also the ADS7861 Compatibility section).  
ANALOG  
This section addresses the analog input circuit, the ADCs, and the reference design of the device.  
Analog Inputs  
Each ADC is fed by an input multiplexer, as shown in Figure 32. Each multiplexer is either used in a fully-  
differential 2:1 configuration (as described in Table 1) or a pseudo-differential 3:1 configuration (as shown in  
Table 2). The channel selection is performed using bits C1 and C0 in the SDI register (see also the Serial Data  
Input section).  
CHx1+  
CHx1-  
ADC+  
Input  
MUX  
ADC-  
CHx0+  
CHx0-  
Figure 32. Input Multiplexer Configuration  
The input path for the converter is fully differential and provides a common-mode rejection of 72 dB at 100 kHz.  
The high CMRR also helps suppress noise in harsh industrial environments.  
Table 1. Fully Differential 2:1 Multiplexer Configuration  
C1  
0
C0  
0
ADC+  
CHx0+  
CHx1+  
ADC–  
CHx0–  
CHx1–  
1
1
Table 2. Pseudo-Differential 3:1 Multiplexer Configuration  
C1  
0
C0  
0
ADC+  
CHx0+  
CHx1–  
CHx1+  
ADC–  
CHx0–  
CHx0–  
CHx0–  
0
1
1
0
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Each 2-pF sample-and-hold capacitor (defined as CS in Figure 1) is connected via switches to the multiplexer  
output. Opening the switches holds the sampled data during the conversion process. After finishing the  
conversion, both capacitors are pre-charged for the duration of one clock cycle to the voltage present at the  
REFIN pin. After the pre-charging, the multiplexer outputs are connected to the sampling capacitors again. The  
voltage at the analog input pin is usually different from the reference voltage; therefore, the sample capacitors  
must be charged to within one-half LSB for 12-bit accuracy during the acquisition time tACQ (see the Timing  
Characteristics).  
Acquisition time is indicated with the BUSY signal being held low. tACQ starts by closing the input switches (after  
finishing the previous conversion and pre-charging) and finishes with the rising edge of the CONVST signal. If  
the ADS7863A operates at full speed, the acquisition time is typically 62.5 ns.  
The minimum –3-dB bandwidth of the driving operational amplifier can be calculated as shown in Equation 1:  
ln(2) ´ (n + 1)  
f
=
-3dB  
2p ´ tACQ  
where:  
n = 12 is the device resolution  
(1)  
With tACQ = 62.5 ns, the minimum bandwidth of the driving amplifier is 23 MHz. The required bandwidth can be  
lower if the application allows a longer acquisition time.  
A gain error occurs if a given application does not fulfill the settling requirement shown in Equation 1. As a result  
of pre-charging the capacitors, linearity and THD are not directly affected, however.  
The OPA365 from Texas Instruments is recommended as a driver; in addition to offering the required bandwidth,  
the OPA365 provides a low offset and also offers excellent THD performance.  
The phase margin of the driving operational amplifier is usually reduced by the ADC sampling capacitor. A  
resistor placed between the capacitor and amplifier limits this effect; therefore, an internal 200-resistor (RSER  
is placed in series with the switch. The switch resistance (RSW) is typically 50 (see Figure 1).  
)
The differential input voltage range of the ADC is ±VREF, the voltage at the REFIN pin.  
The voltage to all inputs must be kept within the 0.3-V limit below AGND and above AVDD while not allowing dc  
current to flow through the inputs. Current is only necessary to recharge the sample-and-hold capacitors.  
Analog-to-Digital Converter (ADC)  
The ADS7863A includes two SAR-type, 2-MSPS, 12-bit ADCs (see the functional block diagram on the front  
page of this data sheet).  
CONVST  
The analog inputs are held with the rising edge of the CONVST (conversion start) signal. The CONVST setup  
time referred to the next rising edge of CLOCK (system clock) is 10 ns (minimum). The conversion automatically  
starts with the rising CLOCK edge. CONVST should not be issued during a conversion, that is, when BUSY is  
high.  
RD (read data) and CONVST can be shorted to minimize necessary software and wiring. The RD signal is  
triggered by the ADS7863A on the falling CLOCK edge. Therefore, the combined signals must be activated with  
the rising CLOCK edge. The conversion then starts with the subsequent rising CLOCK edge.  
CLOCK  
The ADC uses an external clock in the range of 1 MHz to 32 MHz. 12 clock cycles are needed for a complete  
conversion; the following clock cycle is used for pre-charging the sample capacitors and a minimum of two clock  
cycles are required for the sampling. With a minimum of 16 clocks used for the entire process, one clock cycle is  
left for the required setup and hold times along with some margin for delay caused by layout. The clock input can  
remain low between conversions (after applying the 16th falling edge to complete a running conversion). The  
input can also remain low after applying the 14th falling edge during a DAC register write access if the device is  
not required to perform a conversion on CHBx (for example, during an initiation phase after power-up).  
The CLOCK duty cycle should be 50%. However, the ADS7863A functions properly with a duty cycle between  
30% and 70%.  
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RESET  
The ADS7863A features an internal power-on-reset (POR) function. When the device is powered up, the POR  
sets the device in default mode when AVDD reaches 1.8 V. An external software reset can be issued using the  
SDI register bits A[2:0] (see the Digital section).  
REFIN  
The reference input is not buffered and is directly connected to the ADC. The converter generates spikes on the  
reference input voltage because of internal switching. Therefore, an external capacitor to the analog ground  
(AGND) should be used to stabilize the reference input voltage. This capacitor should be at least 470 nF.  
Ceramic capacitors (X5R type) with values up to 1 μF are commonly available as SMD in 0402 size.  
REFOUT  
The ADS7863A includes a low-drift, 2.5-V internal reference source. This source feeds a 10-bit string DAC that is  
controlled via the serial interface. As a result of this architecture, the voltage at the REFOUT pin is programmable  
in 2.44-mV steps and can be adjusted to specific application requirements without the use of additional external  
components.  
However, the DAC output voltage should not be programmed below 0.5 V to ensure the correct functionality of  
the reference output buffer. This buffer is connected between the DAC and the REFOUT pin, and is capable of  
driving the capacitor at the REFIN pin. A minimum of 470 nF is required to keep the reference stable (see the  
REFIN section). For applications that use an external reference source, the internal reference can be disabled  
using bit RP in the SDI register (see the Digital section). The settling time of the REFOUT pin is 500 μs  
(maximum) with the reference capacitor connected. The default value of the REFOUT pin after power-up is 2.5 V.  
For operation with a 2.7-V analog supply and a 2.5-V reference, the internal reference buffer requires a rail-to-rail  
input and output. Such buffers typically contain two input stages; when the input voltage passes the mid-range  
area, a transition occurs at the output because of switching between the two input stages. In this voltage range,  
rail-to-rail amplifiers generally show a very poor power-supply rejection.  
As a result of this poor performance, the ADS7863A buffer has a fixed transition at DAC code 509 (1FDh). At this  
code, the DAC may show a jump of up to 10 mV in the transfer function.  
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DIGITAL  
This section addresses the timing and control of the ADS7863A serial interface.  
Serial Data Input (SDI)  
The serial data input or SDI pin is coupled to RD and clocked into the ADS7863A on each falling CLOCK edge.  
The data word length of the SDI register is 12 bits. Table 3 shows the register structure. Data must be  
transferred MSB-first. Table 4 through Table 6 describe specific bits of this register. The default value of this  
register after power-up is 000h.  
Table 3. SDI Register Contents  
SDI REGISTER BIT  
11  
10  
9
8
7
6
5
4
3
2
1
0
C1  
C0  
P1  
P0  
DP  
N
AN  
RP  
S4  
A2  
A1  
A0  
Table 4. C1 and C0: Channel Selection  
ADC A, B  
POSITIVE INPUT  
C1  
C0  
NEGATIVE INPUT  
CHA0–, CHB0–  
CHA0–, CHB0–  
CHA0–, CHB0–  
CHA1–, CHB1–  
0
0
1
1
0
1
0
1
CHA0+, CHB0+  
CHA1–, CHB1–  
CHA1+, CHB1+  
CHA1+, CHB1+  
Table 5. P1 and P0: Additional Features Enable  
P1  
P0  
0
FUNCTION  
0
0
1
1
Additional features are not changed  
Update additional features  
1
0
Reserved for factory test (do not use)  
Additional features are not changed  
1
DP:  
N:  
Deep power-down enable (1 = device in deep power-down mode)  
NAP power-down enable (1 = device in NAP power-down mode)  
AN:  
RP:  
S4:  
AutoNAP power-down enable (1 = device in AutoNAP power-down mode)  
Reference power-down(1 = reference turned off)  
Special read mode for Modes II and IV (1 = special mode enabled)  
Table 6. A2, A1, and A0: DAC Control and Device Reset  
A2  
0
A1  
0
A0  
0
FUNCTION  
No action  
0
0
1
DAC write with next access  
No action  
0
1
0
0
1
1
DAC read with next access  
No action  
1
0
0
1
0
1
Device reset  
1
1
0
No action  
1
1
1
No action  
16  
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All additional features become active with the rising edge of the 12th CLOCK signal after issuing the RD pulse.  
The reference DAC is controlled by the 12-bit DAC register that can also be accessed using the SDI pin (refer to  
Figure 41 for details). Table 7 shows the content of this register; the default value after power-up is 3FFh.  
Table 7. DAC Register Contents  
DAC REGISTER CONTENT  
11  
10  
9
8
7
6
5
4
3
2
1
0
X(1)  
X
MSB  
Bit 8  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(1) X = don't care.  
Serial Data Output (SDOx)  
Converted data on the SDOx pins become valid with the third falling CLOCK edge after generating an RD pulse.  
The following sections explain the different modes of operation in detail.  
The digital output code format of the ADS7863A is binary twos complement, as shown in Table 9. Conversion  
results can be read out multiple times until a new conversion is issued from the CONVST input.  
Timing and Control  
IMPORTANT:  
Consider the detailed timing diagram (Figure 2) and CONVST timing diagram (Figure 3) within the Timing  
Characteristics section. For maximum data throughput, the descriptions and diagrams given in this data sheet  
assume that the CONVST and RD pins are tied together. Note that these pins can also be controlled  
independently.  
Device operation can be configured in four different modes by using the M0 and M1 mode pins, as shown in  
Table 8.  
Pin M0 sets either manual or automatic channel selection. In manual mode, the SDI register bits C[1:0] are used  
to select between channels CHx0 and CHx1; in automatic operation, the SDI register bits C[1:0] are ignored and  
channel selection is controlled by the device after each conversion. Pin M1 selects between serial data being  
transmitted simultaneously on both outputs SDOA and SDOB for each channel respectively, or using only the  
SDOA output for transmitting data from both channels (see Figure 33 through Figure 40 and the associated text  
for more information).  
Table 8. M0, M1 Truth Table  
M0  
0
M1  
0
CHANNEL SELECTION  
Manual (via SDI)  
SDOx USED  
SDOA and SDOB  
0
1
Manual (via SDI)  
Automatic  
SDOA only  
1
0
SDOA and SDOB  
SDOA only  
1
1
Automatic  
Additionally, the SDI pin is used for controlling device functionality; see the Serial Data Input section for details.  
Table 9. ADS7863A Output Data Format  
DIFFERENTIAL INPUT VOLTAGE  
(CHxx+) – (CHxx–)  
INPUT VOLTAGE AT CHxx+  
(CHxx– = VREF = 2.5 V)  
HEXADECIMAL  
CODE  
DESCRIPTION  
Positive full-scale  
Mid-scale  
BINARY CODE  
0111 1111 1111  
0000 0000 0000  
1111 1111 1111  
VREF  
0V  
5 V  
2.5 V  
7FF  
000  
FFF  
Mid-scale – 1LSB  
–VREF / 4096  
2.49878 V  
Negative full-  
scale  
–VREF  
0 V  
1000 0000 0000  
800  
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Mode I  
With the M0 and M1 pins are both set to '0', the device enters manual channel control operation and outputs data  
on both SDOA and SDOB, respectively. The SDI pin switches between the channels. A conversion is initiated by  
bringing CONVST high.  
16 clock cycles are required to perform a single conversion. With the CONVST rising edge, the ADS7863A  
switches asynchronously to the external CLOCK from sample to hold mode.  
After a delay (t12), the BUSY output pin goes high and remains high for the duration of the conversion cycle. On  
the falling edge of the second CLOCK cycle, the ADS7863A latches in the channel for the next conversion cycle,  
depending on the status of the SDI register bits C[1:0]. CS must be brought low to enable both serial outputs.  
Data are valid on the falling edge of every 16 clock cycles per conversion. The first two bits are set to '0'. The  
subsequent data contain the 12-bit conversion result (the most significant bit is transferred first), followed by two  
'0's (see Figure 2 and Figure 33).  
1
16  
1
16  
CLOCK  
CONVST  
SDI  
C[1:0] = 11 ® Convert CHx1 Next  
C[1:0] = 00 ® Convert CHx0 Next  
C[1:0] = 00 ® Convert CHx0 Next  
P[1:0] = 11 ® SDI Features Not Used  
P[1:0] = 00 ® SDI Features Not Used  
P[1:0] = 00 ® SDI Features Not Used  
M0  
M1  
RD  
CS  
High-Z  
High-Z  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
SDOA  
Previous 12-Bit Data CHAx  
12-Bit Data CHA1  
0
SDOB  
BUSY  
Previous 12-Bit Data CHBx  
12-Bit Data CHB1  
Previous Conversion of Both CHxx  
Conversion of Both CHx1  
Conversion of Both CHx0  
0 ms  
0.5 ms  
1.0 ms  
Figure 33. Mode I Timing Diagram (M0 = 0, M1 = 0)  
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Mode II  
With M0 = 0 and M1 = 1, the device also operates in manual channel control mode and outputs data on the  
SDOA pin only when SDOB is set to 3-state. All other pins function in the same manner as they do in Mode I.  
Because 32 clock cycles are required to output the results from both ADCs (instead of 16 cycles, if M1 = 0), the  
device requires 1.0 μs to perform a complete conversion or read cycle. If the CONVST signal is issued every 0.5  
μs (required for the RD signal) as in Mode I, every second pulse is ignored, as shown in Figure 34.  
Output data consist of a '0' followed by an ADC indicator ('0' for CHAx or '1' for CHBx), 12 bits of conversion  
results, and another '00'.  
16  
1
16  
1
16  
1
16  
1
16  
1
1
1
CLOCK  
CONVST  
SDI  
Every 2nd  
Every 2nd  
Every 2nd  
CONVST  
Is Ignored  
CONVST  
Is Ignored  
CONVST  
Is Ignored  
C[1:0] = 00 ® CHx0 Next  
C[1:0] Is Ignored  
C[1:0] = 11 ® CHx1 Next  
C[1:0] Is Ignored  
C[1:0] = 00 ® CHx0 Next  
C[1:0] Is Ignored  
P[1:0] = 00 ® No Features  
P[1:0] = 00 ® No Features  
P[1:0] = 11 ® No Features  
P[1:0] = 11 ® No Features  
P[1:0] = 00 ® No Features  
P[1:0] = 00 ® No Features  
M0  
M1  
RD  
CS  
CHx  
B
B
Previous 12-Bit  
Data CHAx  
12-Bit  
A
12-Bit  
12-Bit  
A
12-Bit  
12-Bit  
A
SDOA  
SDOB  
BUSY  
Data CHA0  
Data CHB0  
Data CHA1  
Data CHB1  
Data CHA0  
CHx  
High-Z  
Previous 12-Bit  
Data CHBx  
No Conversion,  
No Conversion,  
Previous Conversion  
of Both CHxx  
Conversion  
Conversion  
Conversion  
Read Access Only  
Read Access Only  
of Both CHx0  
of Both CHx1  
of Both CHx0  
0 ms  
0.5 ms  
1.0 ms  
1.5 ms  
2.0 ms  
2.5 ms  
3.0 ms  
Figure 34. Mode II Timing Diagram (M0 = 0, M1 = 1)  
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Mode III  
With M0 = 1 and M1 = 0, the device automatically cycles between the differential inputs (ignoring the SDI register  
bits C[1:0]) while offering the conversion result of CHAx on SDOA and the conversion result of CHBx on SDOB  
(as shown in Figure 35).  
Output data consist of a channel indicator ('0' for CHx0 or '1' for CHx1), followed by a '0', 12 bits of conversion  
results, and another '00'.  
1
16  
1
16  
CLOCK  
CONVST  
SDI  
C[1:0] is ignored  
P[1:0] = 00 ® SDI features are not used  
C[1:0] is ignored  
P[1:0] = 11 ® SDI features are not used  
C[1:0] is ignored  
P[1:0] = 11 ® SDI features are not used  
Both channel 0s are converted first,  
followed by conversion of both channel 1s.  
M0  
M1  
RD  
CS  
CH1  
SDOA  
Previous 12-Bit Data CHAx  
CH0  
CH0  
12-Bit Data CHA0  
12-Bit Data CHA1  
CH1  
SDOB  
BUSY  
Previous 12-Bit Data CHBx  
12-Bit Data CHB0  
12-Bit Data CHB1  
Previous Conversion of Both CHxx  
Conversion of Both CHx0  
Conversion of Both CHx1  
0 ms  
0.5 ms  
1.0 ms  
Figure 35. Mode III Timing Diagram (M0 = 1, M1 = 0)  
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Mode IV  
In the same way as Mode II, Mode IV uses the SDOA output line exclusively to transmit data while the  
differential channels are switched automatically. Following the first conversion after M1 goes high, the SDOB  
output 3-states (as shown in Figure 36).  
Output data consist of a channel indicator ('0' for CHx0 or '1' for CHx1), followed by the ADC indicator ('0' for  
CHAx or '1' for CHBx), 12 bits of conversion results, and end with '00'.  
16  
1
16  
1
16  
1
16  
16  
1
1
1
1
CLOCK  
Every 2nd  
CONVST  
Is Ignored  
Every 2nd  
CONVST  
Is Ignored  
Every 2nd  
CONVST  
Is Ignored  
CONVST  
SDI  
C[1:0] is Ignored  
P[1:0] = 00 ® No Features  
C[1:0] is Ignored  
P[1:0] = 00 ® No Features  
C[1:0] is Ignored  
P[1:0] = 00 ® No Features  
C[1:0] is Ignored  
P[1:0] = 00 ® No Features  
C[1:0] is Ignored  
P[1:0] = 00 ® No Features  
C[1:0] is Ignored  
P[1:0] = 00 ® No Features  
M0  
M1  
Both channel 0s are converted first,  
followed by conversion of both channel 1s.  
RD  
CS  
CHx  
0 A  
0 B  
1 A  
1 B  
0 A  
Previous 12-Bit  
Data CHAx  
12-Bit  
12-Bit  
12-Bit  
12-Bit  
12-Bit  
SDOA  
Data CHA0  
Data CHB0  
Data CHA1  
Data CHB1  
Data CHA0  
CHx  
High-Z  
Previous 12-Bit  
Data CHBx  
SDOB  
BUSY  
Previous Conversion  
of Both CHxx  
Conversion  
No Conversion,  
Read Access Only  
Conversion  
No Conversion,  
Read Access Only  
Conversion  
of Both CHx0  
of Both CHx1  
of Both CHx0  
0 ms  
0.5 ms  
1.0 ms  
1.5 ms  
2.0 ms  
2.5 ms  
3.0 ms  
Figure 36. Mode IV Timing Diagram (M0 = 1, M1 = 1)  
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Special Mode II (Not ADS7861-Compatible)  
For Mode II, a special read mode is available in the ADS7863A where both data results can be read out,  
triggered by a single RD pulse. To activate this mode, bit S4 in the SDI register must be set to '1' (see also the  
Serial Data Input section).  
The CONVST and RD pins can remain tied together, but do not need to be issued every 16 CLOCK cycles.  
Output data are presented on both terminals, SDOA and SDOB. Figure 37 illustrates the special read mode.  
16  
1
16  
1
16  
1
16  
1
16  
1
1
1
CLOCK  
CONVST  
SDI  
C[1:0] = 00 ® CHx0  
C[1:0] = 11 ® CHx1  
C[1:0] = 11 ® CHx1  
C[1:0] = 11 ® CHx1  
P[1:0] = 11 ® No Updates  
® S4 Still = 1  
P[1:0] = 01 ® Features ON  
® S4 = 1  
P[1:0] = 11 ® No Updates  
® S4 Still = 1  
P[1:0] = 11 ® No Updates  
® S4 Still = 1  
M0  
M1  
RD  
CS  
B
B
Previous 12-Bit  
Data CHAx  
12-Bit  
A
12-Bit  
12-Bit  
A
12-Bit  
12-Bit  
SDOA  
SDOB  
BUSY  
A
Data CHA0  
Data CHB0  
Data CHA1  
Data CHB1  
Data CHA1  
High-Z  
Previous 12-Bit  
Data CHBx  
Previous Conversion  
of Both CHxx  
Conversion  
No Conversion,  
Read Access Only  
Conversion  
No Conversion,  
Read Access Only  
Conversion  
of Both CHx1  
of Both CHx0  
of Both CHx1  
0 ms  
0.5 ms  
1.0 ms  
1.5 ms  
2.0 ms  
2.5 ms  
3.0 ms  
Figure 37. Special Mode II Timing Diagram (M0 = 0, M1 = 1, S4 = 1)  
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Special Mode IV (Not ADS7861-Compatible)  
Analogous to Special Mode II, the device also offers a special read mode for Mode IV in which both data results  
of a conversion can be read, triggered by a single RD pulse. In this case as well, bit S4 in the SDI register must  
be set to '1' while the CONVST and RD pins can still be tied together .  
As with Special Mode II, these two pins do not need to be issued every 16 CLOCK cycles. Data are available on  
the SDOA pin.  
This special read mode (shown in Figure 38) is not available in Mode I or Mode III.  
16  
1
16  
1
16  
1
16  
1
16  
1
1
1
CLOCK  
CONVST  
SDI  
C[1:0] is Ignored  
C[1:0] is Ignored  
C[1:0] is Ignored  
C[1:0] is Ignored  
P[1:0] = 01 ® Features ON  
® S4 = 1  
P[1:0] = 11 ® No Updates  
® S4 Still = 1  
P[1:0] = 11 ® No Updates  
® S4 Still = 1  
P[1:0] = 11 ® No Updates  
® S4 Still = 1  
M0  
M1  
Both channel 0s are converted first,  
followed by conversion of both channel 1s.  
RD  
CS  
CHX  
CHX  
0 A  
0 B  
1 A  
1 B  
0 A  
Previous 12-Bit  
Data CHAx  
12-Bit  
12-Bit  
12-Bit  
12-Bit  
12-Bit  
SDOA  
Data CHA0  
Data CHB0  
Data CHA1  
Data CHB1  
Data CHA0  
High-Z  
Previous 12-Bit  
Data CHBx  
SDOB  
BUSY  
Previous Conversion  
of Both CHxx  
Conversion  
No Conversion,  
Read Access Only  
Conversion  
No Conversion,  
Read Access Only  
Conversion  
of Both CHx0  
of Both CHx1  
of Both CHx0  
0 ms  
0.5 ms  
1.0 ms  
1.5 ms  
2.0 ms  
2.5 ms  
3.0 ms  
Figure 38. Special Mode IV Timing Diagram (M0 = 1, M1 = 1, S4 = 1)  
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Pseudo-Differential Mode I (Not ADS7861-Compatible)  
In Mode I, the device input multiplexers can also operate in a pseudo-differential manner. In this case, the SDI  
bits (C[1:0]) are used to choose the channels accordingly.  
For more details, see the Serial Data Input section. Data are available on both output terminals, SDOA and  
SDOB.  
The input multiplexer cannot be used for pseudo-differential signals in Mode III or Mode IV.  
16  
1
16  
1
16  
1
16  
1
16  
1
1
1
CLOCK  
CONVST  
SDI  
C[1:0] = 00 ® CHx0+, CHx0- C[1:0] = 01 ® CHx1-, CHx0- C[1:0] = 10 ® CHx1+, CHx0- C[1:0] = 00 ® CHx0+, CHx0- C[1:0] = 01 ® CHx1-, CHx0- C[1:0] = 10 ® CHx1+, CHx0-  
P[1:0] = 00 ® Features OFF  
P[1:0] = 11 ® Features OFF  
P[1:0] = 00 ® Features OFF  
P[1:0] = 00 ® Features OFF  
P[1:0] = 11 ® Features OFF  
P[1:0] = 00 ® Features OFF  
M0  
M1  
RD  
CS  
12-Bit Data  
12-Bit Data  
12-Bit Data  
12-Bit Data  
12-Bit Data  
Previous 12-Bit  
Data CHAx  
SDOA  
CHA0+, CHA0-  
CHA1-, CHA0-  
CHA1+, CHA0-  
CHA0+, CHA0-  
CHA1-, CHA0-  
12-Bit Data  
12-Bit Data  
12-Bit Data  
12-Bit Data  
12-Bit Data  
Previous 12-Bit  
Data CHBx  
SDOB  
BUSY  
CHB0+, CHB0-  
CHB1-, CHB0-  
CHB1+, CHB0-  
CHB0+, CHB0-  
CHB1-, CHB0-  
Conversion of Both  
Conversion of Both  
Conversion of Both  
Conversion of Both  
Conversion of Both  
Previous Conversion  
of Both CHxx  
CHx0+, CHx0-  
CHx1-, CHx0-  
CHx1+, CHx0-  
CHx0+, CHx0-  
CHx1-, CHx0-  
0 ms  
0.5 ms  
1.0 ms  
1.5 ms  
2.0 ms  
2.5 ms  
3.0 ms  
Figure 39. Pseudo-Differential Mode I (M0 = 0, M1 = 0)  
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Pseudo-Differential Mode II (Not ADS7861-Compatible)  
In Mode II, the device input multiplexers can also operate in a pseudo-differential configuration. In this case,  
output data are available on terminal SDOA only, while SDOB is held in 3-state.  
Channel switching is performed by setting the C[1:0] bits in the SDI register accordingly (see also the Serial Data  
Input section).  
The input multiplexer cannot be used for pseudo-differential signals in Mode III or Mode IV.  
16  
1
16  
1
16  
1
16  
1
16  
1
1
1
CLOCK  
CONVST  
SDI  
Every 2nd  
Every 2nd  
Every 2nd  
CONVST  
Is Ignored  
CONVST  
Is Ignored  
CONVST  
Is Ignored  
C[1:0] = 00 ® CHx0+, CHx0- C[1:0] Is Ignored  
C[1:0] = 01 ® CHx1-, CHx0- C[1:0] Is Ignored  
C[1:0] = 10 ® CHx1+, CHx0- C[1:0] Is Ignored  
P[1:0] = 00 ® Features OFF  
P[1:0] = 00 ® Features OFF  
P[1:0] = 11 ® Features OFF  
P[1:0] = 11 ® Features OFF  
P[1:0] = 00 ® Features OFF  
P[1:0] = 00 ® Features OFF  
M0  
M1  
RD  
CS  
B
B
12-Bit Data  
A
12-Bit Data  
12-Bit Data  
12-Bit Data  
12-Bit Data  
A
Previous 12-Bit  
Data CHAx  
SDOA  
SDOB  
BUSY  
A
CHA0+, CHA0-  
CHB0+, CHB0-  
CHA1-, CHA0-  
CHB1-, CHB0-  
CHA1+, CHA0-  
High-Z  
Previous 12-Bit  
Data CHBx  
Conversion of Both  
Conversion of Both  
Conversion of Both  
Previous Conversion  
of Both CHxx  
No Conversion,  
Read Data Only  
No Conversion,  
Read Data Only  
CHx0+, CHx0-  
CHx1-, CHx0-  
CHx1+, CHx0-  
0 ms  
0.5 ms  
1.0 ms  
1.5 ms  
2.0 ms  
2.5 ms  
3.0 ms  
Figure 40. Pseudo-Differential Mode II (M0 = 0, M1 = 1)  
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Programming the Reference DAC (Not ADS7861-Compatible)  
The internal reference DAC can be set by issuing an RD pulse while providing an SDI word with P[1:0] = 01 and  
A[2:0] = 001. Thereafter, a second RD pulse must be generated with an SDI word starting with the first two bits  
ignored, followed by the actual 10-bit DAC value (as shown in Figure 41).  
To verify the DAC setting, an RD pulse must be generated while providing an SDI word containing P[1:0] = 01  
and A[2:0] = 011 to initialize the DAC read access. Triggering the RD line again causes the SDOA output to send  
'0000' followed by the 10-bit DAC value and another '00'. During the second RD access, data present on SDI are  
ignored, while in Mode I and Mode III valid conversion data for channel B are present on SDOB; the conversion  
results of channel A are lost. The default value of the DAC register after power-up is 3FFh, corresponding to a  
2.5-V reference voltage on the REFOUT pin.  
16  
1
16  
1
16  
1
16  
1
16  
1
1
1
CLOCK  
CONVST  
10-Bit  
SDI  
DAC Value  
C[1:0] = 00 ® CHx0 is Next  
C[1:0] = 11 ® CHx1 is Next  
Data Interpreted as  
DAC Value Only  
C[1:0] = 00 ® CHx0 is Next C[1:0] = '00' ® CHx0 is Next  
P[1:0] = 01 ® Features ON  
A[2:0] = 001 ® Write DAC  
P[1:0] = 01 ® Features ON  
A[2:0] = 011 ® Read DAC  
SDI Data Ignored  
P[1:0] = 00 ® No Features  
P[1:0] = '00’ ® No Features  
M0  
M1  
RD  
CS  
Previous 12-Bit  
Data CHAx  
12-Bit  
Data CHA0  
12-Bit  
Data CHA0  
10-Bit  
DAC Value  
12-Bit  
Data CHA1  
12-Bit  
Data CHA0  
SDOA  
Previous 12-Bit  
Data CHBx  
12-Bi  
Data CHB0  
12-Bit  
Data CHB0  
12-Bit  
Data CHB1  
12-Bit  
Data CHB1  
12-Bit  
Data CHB0  
SDOB  
BUSY  
Previous Conversion  
of Both CHxx  
Conversion of  
Both CHx0  
Conversion of  
Both CHx0  
Conversion of  
Both CHx1  
Conversion of  
Both CHx1  
Conversion of  
Both CHx0  
0 ms  
0.5 ms  
1.0 ms  
1.5 ms  
2.0 ms  
2.5 ms  
3.0 ms  
Figure 41. DAC Write and Read Access Timing Diagram  
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Power-Down Modes and Reset (Not ADS7861-Compatible)  
The device has a comprehensive built-in power-down feature. There are three power-down modes: deep power-  
down, NAP power-down, and auto-NAP power-down. All three power-down modes are activated with the 12th  
falling CLOCK edge of the SDI access, during which the related bit asserts (DP = 1, N = 1, or AN = 1). All modes  
are deactivated by de-asserting the respective bit in the SDI register. The SDI register contents are not affected  
by the power-down modes. Any ongoing conversion aborts when deep or NAP power-down is initiated. Table 10  
lists the differences among the three power-down modes.  
In deep power-down mode, all functional blocks except the digital interface are disabled. The bias currents of the  
analog block are turned off. In this mode, power dissipation reduces to 1 μA within 2 μs. The wake-up time from  
deep power-down mode is 1 μs.  
In NAP power-down mode, the device turns off the biasing of the comparator and the mid-voltage buffer within  
200 ns. The device goes into NAP power-down mode regardless of the conversion state.  
The auto-NAP power-down mode is very similar to NAP mode. The only differences are the methods of powering  
down and waking up the device. The SDI register bit AN is only used to enable or disable this feature. If the auto-  
NAP mode is enabled, the device turns off the biasing automatically after finishing a conversion; thus, the end of  
conversion actually activates the auto-NAP power-down. The device powers down within 200 ns in this mode, as  
well. Triggering a new conversion by applying a CONVST pulse puts the device back into normal operation and  
automatically starts a new conversion six CLOCK cycles later. Therefore, a complete conversion cycle takes 19  
CLOCK cycles; thus, the maximum throughput rate in auto-NAP power-down mode is reduced to 1.68 MSPS.  
To issue a device reset, an RD pulse must be generated along with an SDI word containing A[2:0] = 101. With  
the 12th falling edge after generating the RD pulse, the entire device (including the serial interface) is forced into  
reset. After approximately 500 ns, the serial interface becomes active again.  
Table 10. Power-Down Modes  
POWER-DOWN  
TYPE  
ENABLED  
BY  
ACTIVATION  
TIME  
RESUMED  
BY  
DISABLED  
BY  
ACTIVATED BY  
13th clock  
REACTIVATION TIME  
Deep  
NAP  
DP = 1  
N = 1  
2μs  
DP = 0  
N = 0  
1 μs  
DP = 0  
N = 0  
13th clock  
200ns  
3 clocks  
Each end of  
conversion  
Auto-NAP  
AN = 1  
200ns  
CONVST pulse  
3 clocks  
AN = 0  
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ADS7861 COMPATIBILITY  
The ADS7863AIDBQ is pin-compatible with the ADS7861E, ADS7861EB, and ADS7861EG4. However, there are  
some differences between the two devices that must be considered when migrating from the ADS7861 to the  
ADS7863A in an existing design.  
SDI versus A0  
One of the differences is that pin 16 (A0), which updates the internal SDI register of the ADS7863A, is used in  
conjunction with M0 to select the input channel on the ADS7861.  
In an existing design, if the ADS7861 is used in two-channel mode (M0 = 0) and the status of the A0 pin is  
unchanged within the first four clock cycles after issuing a conversion start (CONVST rising edge), the  
ADS7863A acts similarly to the ADS7861 and converts either channels CHx0 (if SDI is held low during the entire  
period) or channels CHx1 (if SDI is held high during the entire period). Figure 34 describes the behavior of the  
ADS7863A in such a situation.  
The ADS7863A can also be used to replace the ADS7861 when run in four-channel mode (M0 = 1). In this case,  
the A0 pin is held static (high or low) which is also required in the case of SDI to prevent accidentally updating  
the SDI register.  
In both cases, the additional features of the ADS7863A (pseudo-differential input mode, programmable reference  
voltage output, and the different power-down modes) cannot be accessed but the hardware and software remain  
backward-compatible to the ADS7861.  
REFIN  
The ADS7863A offers an unbuffered REFIN input with a code-dependent input impedance while featuring a  
programmable and buffered reference output (REFOUT). The ADS7861 offers a high-impedance (buffered)  
reference input. If an existing ADS7861-based design uses the internal reference of the device and relies on an  
external resistor divider to adjust the input voltage range of the ADC, migration to ADS7863A requires one of the  
following conditions:  
a software change to setup the internal reference DAC properly via SDI while removing the external resistors,  
or  
an additional external buffer between the resistor divider and the required 470-nF (minimum) capacitor on the  
REFIN input.  
In the latter case, while the capacitor stabilizes the reference voltage during the entire conversion, the buffer  
must recharge the capacitor by providing an average current only. The required minimum bandwidth of the buffer  
can be calculated using Equation 2:  
ln(2) ´ 2  
f
=
-3dB  
2p ´ 16 ´ TCLK  
(2)  
The buffer must also be capable of driving the 470-nF load while maintaining stability.  
Timing  
The only timing requirement that may cause the ADS7863A to malfunction in an existing ADS7861-based design  
is the CONVST high time (t1) which is specified to be 20 ns minimum while the ADS7861 works properly with a  
pulse as short as 15 ns. All other required minimum setup and hold times are specified to be either the same as  
or lower than the ADS7863A; therefore, there are no conflicts with the ADS7861 requirements.  
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APPLICATION INFORMATION  
The absolute minimum configuration of the ADS7863A is shown in Figure 42. In this case, the ADS7863A is  
used in dual-channel mode only, with the default settings of the device after power up.  
The input signal for the amplifiers must fulfill the common-mode voltage requirements of the ADS7863A in this  
configuration. The actual values of the resistors and capacitors depend on the bandwidth and performance  
requirements of the application.  
BVDD  
1 mF  
0.1 mF  
ADS7863A  
AVDD  
1
2
3
4
5
6
7
8
9
BGND  
BVDD 24  
SDOA 23  
SDOB 22  
BUSY 21  
CLOCK 20  
CS 19  
BGND  
CHB1+  
CHB1-  
CHB0+  
CHB0-  
CHA1+  
CHA1-  
CHA0+  
CHA0-  
OPA2365  
AGND  
Controller  
Device  
BGND  
RD 18  
AGND  
CONVST 17  
SDI 16  
OPA2365  
BGND  
BVDD  
AGND  
AVDD  
10 REFIN  
11 REFOUT  
12 AGND  
M0 15  
M1 14  
470 nF  
(min)  
AVDD 13  
OPA2365  
0.1 mF (min)  
1 mF  
AGND  
OPA2365  
AGND  
Figure 42. Minimum ADS7863A Configuration  
These values can be calculated using Equation 3, with n = 12 is the device resolution of the ADS7863A.  
ln(2) ´ (n + 1)  
fFILTER  
=
2 ´ p ´ 2 ´ R ´ C  
where:  
n = 12 is the resolution of the ADS7863A  
(3)  
TI recommends using a capacitor value of at least 20 pF.  
Keep the acquisition time in mind; the resistor value can be calculated as shown in Equation 4 for each of the  
series resistors.  
tACQ  
R =  
ln(2) ´ (n + 1) ´ 2 ´ C  
where:  
n = 12 is the resolution of the ADS7863A  
(4)  
29  
Copyright © 2013, Texas Instruments Incorporated  
 
 
 
ADS7863A  
ZHCSBW2 DECEMBER 2013  
www.ti.com.cn  
LAYOUT  
For optimum performance, care should be taken with the physical layout of the ADS7863A circuitry. This  
condition is particularly true if the CLOCK input is approaching the maximum throughput rate. In this case, TI  
recommends having a fixed phase relationship between CLOCK and CONVST. Best performance can be  
achieved when the digital interface is run in SPI mode; thus, the CLOCK signal is switched off after the 16th  
cycle and remains low when CONVST is issued.  
Additionally, the basic SAR architecture is quite sensitive to glitches or sudden changes on the power-supply,  
reference, ground connections, and digital inputs that occur just before latching the output of the analog  
comparator. Therefore, when driving any single conversion for an n-bit SAR converter, there are n windows in  
which large external transient voltages can affect the conversion result. Such glitches might originate from  
switching power supplies, nearby digital logic, or high-power devices. The degree of error in the digital output  
depends on the reference voltage, layout, and the exact timing of the external event. These errors can change if  
the external event also changes in time with respect to the CLOCK input.  
With this possibility in mind, power to the device should be clean and well-bypassed. A 0.1-μF ceramic bypass  
capacitor should be placed as close to the device as possible. In addition, a 1-μF to 10-μF capacitor is  
recommended. If needed, an even larger capacitor and a 5-or 10-series resistor may be used to low-pass  
filter a noisy supply.  
If the reference voltage is external and originates from an operational amplifier, be sure that the reference  
voltage can drive the reference capacitor without oscillation. The connection between the output of the external  
reference driver and REFIN should be of low resistance (10 max) to minimize any code-dependent voltage  
drop on this path.  
Grounding  
The xGND pins should be connected to a clean ground reference. These connections should be kept as short as  
possible to minimize the inductance of these paths. TI recommends using vias connecting the pads directly to the  
ground plane. In designs without ground planes, the ground trace should be kept as wide as possible. Avoid  
connections that are too near the grounding point of a microcontroller or digital signal processor (DSP).  
Depending on the circuit density of the board, placement of the analog and digital components, and the related  
current loops, a single solid ground plane for the entire printed circuit board (PCB) or a dedicated analog ground  
area may be used. In an instance of a separated analog ground area, ensure a low-impedance connection  
between the analog and digital ground of the ADC by placing a bridge underneath (or next to) the ADC.  
Otherwise, even short undershoots on the digital interface with a value lower than –300 mV lead to conduction of  
ESD diodes, causing current flow through the substrate and degrading the analog performance.  
During PCB layout, care should also be taken to avoid any return currents crossing any sensitive analog areas or  
signals. No signal must exceed the limit of –300 mV with respect to the according ground plane. Figure 43  
illustrates the recommended layout of the ground and power-supply connections for both package options.  
Supply  
The ADS7863A has two separate supplies: the BVDD pin for the digital interface and the AVDD pin for all  
remaining circuits.  
BVDD can range from 2.7 V to 5.5 V, allowing the device to easily interface with processors and controllers. To  
limit the injection of noise energy from external digital circuitry, BVDD should be filtered properly. Bypass  
capacitors of 0.1 μF and 10 μF should be placed between the BVDD pin and ground plane.  
AVDD supplies the internal analog circuitry. For optimum performance, a linear regulator (for example, the  
UA7805 family) is recommended to generate the analog supply voltage in the range of 2.7 V to 5.5 V for the  
ADS7863A and the necessary analog front-end circuitry.  
Bypass capacitors should be connected to the ground plane such that the current is allowed to flow through the  
pad of the capacitor (that is, the vias should be placed on the opposite side of the connection between the  
capacitor and the power-supply pin of the ADC).  
30  
Copyright © 2013, Texas Instruments Incorporated  
ADS7863A  
www.ti.com.cn  
ZHCSBW2 DECEMBER 2013  
Digital Interface  
To further optimize device performance, a resistor of 10 to 100 can be used on each digital pin of the  
ADS7863A. In this way, the slew rate of the input and output signals is reduced, limiting the noise injection from  
the digital interface.  
ADS7863AIDBQ  
ADS7863AIRGE  
Figure 43. Optimized Layout Recommendation  
Copyright © 2013, Texas Instruments Incorporated  
31  
PACKAGE OPTION ADDENDUM  
www.ti.com  
10-Dec-2020  
PACKAGING INFORMATION  
Orderable Device  
Status Package Type Package Pins Package  
Eco Plan  
Lead finish/  
Ball material  
MSL Peak Temp  
Op Temp (°C)  
Device Marking  
Samples  
Drawing  
Qty  
(1)  
(2)  
(3)  
(4/5)  
(6)  
ADS7863ADBQ  
ADS7863ADBQR  
ADS7863ARGER  
ACTIVE  
ACTIVE  
ACTIVE  
SSOP  
SSOP  
VQFN  
DBQ  
DBQ  
RGE  
24  
24  
24  
50  
RoHS & Green  
NIPDAU  
Level-3-260C-168 HR  
Level-3-260C-168 HR  
Level-3-260C-168 HR  
-40 to 125  
-40 to 125  
-40 to 125  
ADS7863A  
2500 RoHS & Green  
3000 RoHS & Green  
NIPDAU  
NIPDAU  
ADS7863A  
ADS  
7863A  
ADS7863ARGET  
ACTIVE  
VQFN  
RGE  
24  
250  
RoHS & Green  
NIPDAU  
Level-3-260C-168 HR  
-40 to 125  
ADS  
7863A  
(1) The marketing status values are defined as follows:  
ACTIVE: Product device recommended for new designs.  
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.  
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.  
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.  
OBSOLETE: TI has discontinued the production of the device.  
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance  
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may  
reference these types of products as "Pb-Free".  
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.  
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based  
flame retardants must also meet the <=1000ppm threshold requirement.  
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.  
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.  
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation  
of the previous line and the two combined represent the entire Device Marking for that device.  
(6)  
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two  
lines if the finish value exceeds the maximum column width.  
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information  
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and  
Addendum-Page 1  
PACKAGE OPTION ADDENDUM  
www.ti.com  
10-Dec-2020  
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.  
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.  
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.  
Addendum-Page 2  
GENERIC PACKAGE VIEW  
RGE 24  
VQFN - 1 mm max height  
PLASTIC QUAD FLATPACK - NO LEAD  
Images above are just a representation of the package family, actual package may vary.  
Refer to the product data sheet for package details.  
4204104/H  
PACKAGE OUTLINE  
VQFN - 1 mm max height  
RGE0024H  
PLASTIC QUAD FLATPACK- NO LEAD  
A
4.1  
3.9  
B
4.1  
3.9  
PIN 1 INDEX AREA  
1 MAX  
C
SEATING PLANE  
0.08 C  
0.05  
0.00  
ꢀꢀꢀꢀꢁꢂꢃ“ꢄꢂꢅ  
(0.2) TYP  
2X 2.5  
12  
7
20X 0.5  
6
13  
25  
2X  
SYMM  
2.5  
1
18  
0.30  
PIN 1 ID  
(OPTIONAL)  
24X  
0.18  
24  
19  
0.1  
0.05  
C A B  
C
SYMM  
0.48  
0.28  
24X  
4219016 / A 08/2017  
NOTES:  
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing  
per ASME Y14.5M.  
2. This drawing is subject to change without notice.  
3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.  
www.ti.com  
EXAMPLE BOARD LAYOUT  
VQFN - 1 mm max height  
RGE0024H  
PLASTIC QUAD FLATPACK- NO LEAD  
(3.825)  
2.7)  
(
24  
19  
24X (0.58)  
24X (0.24)  
1
18  
20X (0.5)  
25  
SYMM  
(3.825)  
2X  
(1.1)  
ꢆ‘ꢄꢂꢁꢇꢀ9,$  
TYP  
6
13  
(R0.05)  
7
12  
2X(1.1)  
SYMM  
LAND PATTERN EXAMPLE  
SCALE: 20X  
0.07 MIN  
ALL AROUND  
0.07 MAX  
ALL AROUND  
METAL  
SOLDER MASK  
OPENING  
SOLDER MASK  
OPENING  
METAL UNDER  
SOLDER MASK  
NON SOLDER MASK  
DEFINED  
SOLDER MASK  
DEFINED  
(PREFERRED)  
SOLDER MASK DETAILS  
4219016 / A 08/2017  
NOTES: (continued)  
4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments  
literature number SLUA271 (www.ti.com/lit/slua271).  
5. Solder mask tolerances between and around signal pads can vary based on board fabrication site.  
www.ti.com  
EXAMPLE STENCIL DESIGN  
VQFN - 1 mm max height  
RGE0024H  
PLASTIC QUAD FLATPACK- NO LEAD  
(3.825)  
4X ( 1.188)  
24  
19  
24X (0.58)  
24X (0.24)  
1
18  
20X (0.5)  
SYMM  
(3.825)  
(0.694)  
TYP  
6
13  
25  
(R0.05) TYP  
METAL  
TYP  
7
12  
(0.694)  
TYP  
SYMM  
SOLDER PASTE EXAMPLE  
BASED ON 0.125 mm THICK STENCIL  
EXPOSED PAD  
78% PRINTED COVERAGE BY AREA  
SCALE: 20X  
4219016 / A 08/2017  
NOTES: (continued)  
6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate  
design recommendations..  
www.ti.com  
重要声明和免责声明  
TI 均以原样提供技术性及可靠性数据(包括数据表)、设计资源(包括参考设计)、应用或其他设计建议、网络工具、安全信息和其他资  
源,不保证其中不含任何瑕疵,且不做任何明示或暗示的担保,包括但不限于对适销性、适合某特定用途或不侵犯任何第三方知识产权的暗示  
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TI 所提供产品均受TI 的销售条款 (http://www.ti.com.cn/zh-cn/legal/termsofsale.html) 以及ti.com.cn上或随附TI产品提供的其他可适用条款的约  
束。TI提供所述资源并不扩展或以其他方式更改TI 针对TI 产品所发布的可适用的担保范围或担保免责声明。IMPORTANT NOTICE  
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