ADGM3121BCCZ-R2 datasheet(25/33 Pages) AD

25 / 33 page

Data Sheet

ADGM3121

THEORY OF OPERATION

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Rev. 0 | 25 of 33

Internal Error Status

Where an internal error is detected in the part, it is flagged in the

internal error status bits [7:6] of the SWITCH_DATA register. An

internal error results from an error in the configuration of the part at

power-up.

INTERNAL OSCILLATOR FEEDTHROUGH

The ADGM3121 has an internal oscillator running at a nominal

10MHz. This oscillator drives the charge pump circuitry that pro-

vides the actuation voltage for each of the switch gate electrodes.

Although this oscillator is very low power, the 10MHz signal is

coupled to the switch and can be considered a noise spur on the

switch channels. The magnitude of this feedthrough noise spur is

specified in Table 1 and is typically −92.5dBm when one switch is

on. The VDD level and temperature changes affect the frequency of

the noise spur. For the maximum and minimum frequency ranges

over temperature and voltage supply range, see Table 1.

TYPICAL OPERATING CIRCUIT

Figure 69 shows the typical operating circuit for the ADGM3121.

VDD is connected to 3.3V. EP connects to GND internally. It is

recommended to connect GND using one large pad on the PCB

to short together GND with EP. Figure 69 shows the ADGM3121

configured to use the internal oscillator as the reference clock to the

driver IC control circuit. Place a 0.1nF capacitor rated to at least

100V DC as close as possible to VCP. Place a 0.1uF capacitor rated

to at least 16V DC as close as possible to VDD.

Figure 69. Typical Operating Circuit in the Parallel Digital Interface Mode

ADGM3121BCCZ-R2 データシート(PDF) 25 Page - Analog Devices