RHF1401 datasheet(20/29 Pages) STMICROELECTRONICS

Il numero della parte	RHF1401

Spiegazioni elettronici	Rad-hard 14-bit 20Msps 85mW A/D converter

PDF	29 Pages

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Produttore elettronici	STMICROELECTRONICS [STMicroelectronics]

Homepage	http://www.st.com

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20 / 29 page

Application information

RHF1401

20/29

Figure 23.

Analog current consumption vs. Fs according to value of Rpol polarization

resistances: internal references (for Fin < 10MHz)

Input signal above 10MHz

However, with a higher frequency input signal (for example, in the 10-70MHz range), a high

Rpol value does not supply enough current to the internal amplifiers, thus resulting in

degraded SNR and THD performance. With an input signal in this range, the recommended

value for Rpol is in the 30-50 kΩ range.

7.4

Low sampling rate recommendations

The RHF1401 offers a wide range of sampling rates from 1.5Msps to 20Msps with the

minimum power consumption. However, under the minimum, the performance of the device

deteriorates. Figure 24 shows the degradation in performance at sampling frequencies

under 1.2Msps. The recommended minimum sampling frequency is 1.5Msps.

1113

1517

1921

Fs (Mhz)

100

120

140

Ipol_intref

Ipol_extref

Rpol

REFMODE= 0

REFMODE= 1

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