2. System Overview

The TS4100 is an 8-channel multiplexer with inputs NO0-NO7 and output COM. A channel can be selected via address pins ADDA,

ADDB, and ADDC.

The TS4101 is a dual 4-channel switch/multiplexer with two separate input banks: NO0A-NO3A and NO0B-NO3B with dedicated output

COMA and COMB, respectively. A channel can be selected via address pins ADDA and ADDB.

The TS4102 is a triple single-pole/double-throw (SPDT) switch. When ADDA, ADDB, or ADDC is set to a Low state, the output will be

NCA, NCB, or NCC, respectively. When ADDA, ADDB, or ADDC is set to a High state, the output will be NOA, NOB, or NOC, respec-

tively. Refer to XREF DIGITAL I/O SETTINGS TABLE

Unlike similar switch/multiplexer devices, the TS4100-TS4102 input voltage is independent of the supply voltage. This allows the input

voltage to be greater than the supply voltage while maintaining a flat On-resistance vs. the VNO/VCOM curve. Refer to 3.1 Typical

Performance Characteristics for more information.

2.1 Applications Information

2.1.1 AC Performance Considerations

2.1.2 Off Isolation

Like all switch/multiplexer devices, the off-isolation of the device is measured when the device is off (see Figure 2.8 TS4100-TS4102

Charge Injection Test Setup on page 8). During the OFF state, part of the input signal couples to the output load. To maximize the

off-isolation, maximize your capacitive load and minimize your resistive load. The trade-off is that this can increase the insertion loss of

the device so it must be considered when designing a circuit. The insertion loss is measured when the switch/multiplexer is in the ON

state (see Figure 2.9 TS4100-TS4102 Off-Isolation Test Setup on page 9).

At 10 kHz, the off-isolation of the TS4100-TS4102 is approximately –88 dB. Refer to the Off-Isolation vs. Frequency plot in 3.1 Typical

Performance Characteristics.

2.1.3 Total Harmonic Distortion (THD)

In audio and data acquisition applications, signal fidelity is of a concern. As a result, the THD parameter of the analog mux/switch be-

comes an important factor. Many current analog switch/mux devices on the market implement a design that allow for a large variation of

on-resistance as the input signal is changing. With 1% on-resistance variation over the entire signal swing, the TS4100-TS4102 design

minimizes THD. At 10 kHz, the TS4100-TS4102 exhibits a THD of 0.15% over the entire signal swing.

2.1.4 Bandwidth Considerations

The magnitude of the output resistive load and capacitive load has an impact on the bandwidth of the mux/switch. At dc or close to dc

input signals, a resistive load has the greatest impact where the output voltage is determined primarily by the voltage divider consisting

of the switch on-resistance and the output resistive load. To minimize the ON insertion loss, maximize the resistive load.

As the input frequency increases, the ac impedance of the circuit begins to have an impact on bandwidth of the mux/switch. To counter

this effect, minimize the load capacitance and any stray capacitance that may be present on the board. Also, ensure a board layout that

minimizes signal trace lengths.

TS4100/01/02 Data Sheet

System Overview

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