AD7988-1 AD8641 ADR435 高达1kHz 低于奈奎斯特频率输入信号优化的低功耗数据采集系统

实物图：


图中的电路采用16位、100 kSPS逐次逼近型模数转换器 (ADC)系统，集成驱动放大器，针对最高1 kHz输入信号和 100 kSPS采样速率、功耗低至7.35 mW的系统而优化。
这种方法对于便携式电池供电、要求低功耗的多通道应用 极为有用。它还为那些两次转换突发之间的大部分时间 ADC都处于空闲状态的应用提供了优势。
通常，选择高性能逐次逼近型ADC的驱动放大器处理宽范 围的输入频率。然而，当某个应用需要更低的采样速率 时，便可节省大量功耗，因为降低采样速率会相应地降低 ADC功耗。
若要完全利用通过降低ADC采样速率使功耗下降的优势， 则需要使用低带宽、低功耗放大器。
例如，推荐80 MHz的ADA4841-1 运算放大器(10 V时功耗为 12 mW)与AD7988-1 16位逐次逼近型寄存器(SAR) ADC(100 kSPS时功耗为0.7 mW)一同使用。包括ADR435 基准电压源 (7.5 V时功耗为4.65 mW)在内的总系统功耗在100 kSPS时为 17.35 mW。
对于最高1 kHz的输入带宽和100 kSPS的采样速率，AD8641 3 MHz运算放大器(10 V时功耗为2 mW)可提供出色的信噪 比(SNR)和总谐波失真(THD)性能，并且在100 kSPS时可将 总系统功耗从17.35 mW降低至7.35 mW，降幅达58%。


电路原理图：


BOM表（完整版见附件）：

C1	CAP+	10uF	±10%	RTAJ_B	Yes	Top	20V Tantalum  Capacitor	AVX	TAJB106K020RNJ	FEC 197427
C2	CAP+	10uF	±10%	RTAJ_B	Yes	Top	20V Tantalum  Capacitor	AVX	TAJB106K020RNJ	FEC 197427
C3	CAP	4.7 μF	0.1	C0805	Yes	Top	CAPACITOR CERAMIC,  4.7UF, 16V, X7R, 0805	TAIYO YUDEN	EMK212B7475KG-T	FEC 1853520
C4	CAP	4.7 μF	0.1	C0805	Yes	Top	CAPACITOR CERAMIC,  4.7UF, 16V, X7R, 0805	TAIYO YUDEN	EMK212B7475KG-T	FEC 1853520
C5	CAP+	10uF	±10%	RTAJ_B	Yes	Top	20V Tantalum  Capacitor	AVX	TAJB106K020RNJ	FEC 197427
C6	CAP	4.7 μF	0.1	C0805	Yes	Top	CAPACITOR CERAMIC,  4.7UF, 16V, X7R, 0805	TAIYO YUDEN	EMK212B7475KG-T	FEC 1853520
C7	CAP	4.7 μF	0.1	C0805	Yes	Top	CAPACITOR CERAMIC,  4.7UF, 16V, X7R, 0805	TAIYO YUDEN	EMK212B7475KG-T	FEC 1853520
C8	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C9	CAP+	10uF	±10%	RTAJ_B	Yes	Top	20V Tantalum  Capacitor	AVX	TAJB106K020RNJ	FEC 197427
C10	CAP	0.1uF	±10%	C0805	Yes	Top	CAPACITOR, 0805,  100NF, 50V, X7R	Kemet	C0805C104K5RACTU	FEC 1414664
C11	CAP	10uF	20%	1206	Yes	Top	CAPACITOR CERAMIC  10UF, 25V, X5R, 1206	TAIYO YUDEN	TMK316BJ106ML-T	FEC 1684002
C12	CAP	22 μF	0.2	1206	Yes	Top	CAPACITOR CERAMIC,  22UF, 16V, X5R, 1206	MURATA	GRM31CR61C226KE15L	FEC 182-8815
C13	CAP+	10uF	±10%	RTAJ_B	Yes	Top	20V Tantalum  Capacitor	AVX	TAJB106K020RNJ	FEC 197427
C14	CAP	4u7F	10%	1206	Yes	Top	CAPACITOR CERAMIC,  4.7UF, 16V, X5R, 1206	TAIYO YUDEN	EMK316BJ475KL-T	FEC 6578937
C15	CAP	1uF	±10%	C0805	Yes	Top	CAPACITOR, 0805, 1UF,  50V, X7R	MURATA	GRM21BR71H105KA12L	FEC 1735541
C16	CAP	1uF	±10%	C0805	Yes	Top	CAPACITOR, 0805, 1UF,  50V, X7R	Murata	GRM21BR71H105KA12L	FEC 1735541
C17	CAP	1uF	±10%	C0805	Yes	Top	CAPACITOR, 0805, 1UF,  50V, X7R	MURATA	GRM21BR71H105KA12L	FEC 1735541
C18	CAP	10nF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H103KA01D	FEC 1118178
C19	CAP+	10uF	±10%	RTAJ_B	Yes	Top	20V Tantalum  Capacitor	AVX	TAJB106K020RNJ	FEC 197427
C20	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C21	CAP	1uF	±10%	C0805	Yes	Top	CAPACITOR, 0805, 1UF,  50V, X7R	MURATA	GRM21BR71H105KA12L	FEC 1735541
C22	CAP	1uF	±10%	C0805	Yes	Top	CAPACITOR, 0805, 1UF,  50V, X7R	MURATA	GRM21BR71H105KA12L	FEC 1735541
C23	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	MURATA	GRM188R71H104KA93D	FEC 8820023
C24	CAP	DNP	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  TBD, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	Do Not Place
C25	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C26	CAP	1uF	±10%	C0805	Yes	Top	CAPACITOR, 0805, 1UF,  50V, X7R	MURATA	GRM21BR71H105KA12L	FEC 1735541
C27	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C28	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C29	CAP	DNP	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  TBD, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	Do Not Place
C30	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C31	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C32	CAP	DNP	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  TBD, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	Do Not Place
C33	CAP	10pF	±5%	C0603	Yes	Top	CAP CERAMIC 10PF,  100V, C0G, 0603	AVX	06031A100JAT2A	FEC 1273324
C34	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C35	CAP	2.7nF	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  2700PF, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	FEC 1844178
C36	CAP	DNP	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  TBD, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	Do Not Place
C37	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C38	CAP	DNP	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  TBD, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	Do Not Place
C39	CAP	DNP	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  TBD, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	Do Not Place
C40	CAP	22uF	±10%	1206	Yes	Top	CAPACITOR, 1206, X5R,  16V, 22UF	AVX	1206YD226KAT2A	FEC 1833822
C41	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C42	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023
C43	CAP	DNP	±5%	C0603	Yes	Top	CAPACITOR CERAMIC,  TBD, 50V, C0G/NP0, 0603	TDK	C1608C0G1H272J	Do Not Place
C44	CAP	0.1uF	±10%	C0603	Yes	Top	50V X7R Ceramic  Capacitor	Murata	GRM188R71H104KA93D	FEC 8820023

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