ADGM1004JCPZ-R2 datasheet(28/32 Pages) AD

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ADGM1004

Data Sheet

Rev. D | Page 28 of 32

CRITICAL OPERATIONAL REQUIREMENTS

SYSTEM ERROR CONSIDERATIONS DUE TO

ON-RESISTANCE DRIFT

The RON performance of the ADGM1004 is affected by part to

part variation, channel to channel variation, cycle actuations,

settling time post turn on, bias voltage, and temperature changes

(see Figure 6 to Figure 13).

In a 50 Ω system, the on-resistance drift over switch actuations

(ΔRON) can introduce system inaccuracy. Figure 52 shows the

ADGM1004 connected with the load in a 50 Ω system, where

RS is the source impedance. TO calculate the system error

caused by the ADGM1004 on-resistance drift, use the following

equation:

System Error (%) = ΔR/RLOAD

where:

ΔR is the ADGM1004 on-resistance drift.

RLOAD is the load impedance.

The ADGM1004 on-resistance drift also affects insertion loss,

which must be considered when using the device. To calculate

the on-resistance impact on insertion loss, use the following

equation:

Insertion Loss = 10log(1 + (ΔR/RLOAD))

50Ω

∆R

RLOAD

50Ω

Figure 52. 50 Ω System Representation Where the ADGM1004 is Connected

with the Load

Table 7. System Error and Insertion Loss Error Due to

ADGM1004 RON Drift

On-Resistance Drift

System

Error (%)

Insertion Loss Error (dB)

4.75

9.5

0.39

0.41

FLOATING NODE

The ADGM1004 has no internal impedance to ground, and

charges can develop on the switch terminals leading to unreliable

switch behavior To mitigate this behavior, provide a discharge

path to all switch nodes. Figure 53 to Figure 56 show examples

of cases to avoid where floating nodes can occur when using the

switch. Conditions to avoid include the following:



Leaving the RFx pins open circuit (see Figure 53).



Connecting a series capacitor directly to the switch (see

Figure 54).



Connecting the RFx pin of two switches together directly

or connecting the RFC pin to the RFx pin (see Figure 55

and Figure 56).

RFx

RFC

FLOATING

OPEN CIRCUIT

Figure 53. RFx Pins Left Open Circuit

RFx

RFC

FLOATING

Figure 54. Series Capacitor Directly Connected to MEMS Switch

RFx

RFC

FLOATING

RFx

RFC

Figure 55. RFx Pins of Two MEMS Switches Directly Connected

RFx

RFC

FLOATING

RFC

RFx

Figure 56. RFC Connected to RFx

Provide a discharge path to the switch nodes to avoid floating

nodes. In a typical application, a 50 Ω termination connected to

the switch provides this path. Driving switch nodes with a

device of adequate impedance (<10 M

Ω) provides a discharge

path. If there is no discharge path in the application circuit, add

a 10 MΩ shunt resistor or inductor on the source RFx pin of the

MEMS switch to provide the discharge path. Note that the

shunt resistors introduce leakage. Figure 57 shows an example

of a configuration providing a discharge path.

RFx

RFC

Figure 57. Switch Configuration Providing a Discharge Path

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