3V/5V, 4

Ω, Wideband Quad

2:1 Analog Multiplexer

_______________________________________________________________________________________

7

when V+ = +3V, the guaranteed minimum logic-high

threshold decreases to 2.0V.

Low-Voltage Operation

The MAX4674 operates from a single supply between

+1.8V and +5.5V. At room temperature, it actually

“works” with a single supply near or below +1.7V; as

supply voltage decreases, however, switch on-resis-

tance becomes very high.

Overvoltage Protection

Proper power-supply sequencing is recommended for

all CMOS devices. Do not exceed the absolute maxi-

mum ratings because stresses beyond the listed rat-

ings can cause permanent damage to the device.

Always sequence V+ on first, followed by the logic

inputs and analog signals. If power-supply sequencing

is not possible, add two small signal diodes (D1, D2) in

series with the supply pins for overvoltage protection

(Figure 1).

Adding diodes reduces the analog-signal range to one

diode drop below V+ and one diode drop above GND,

but does not affect the device’s low switch resistance

and low leakage characteristics. Device operation is

unchanged, and the difference between V+ and GND

should not exceed 6V. These protection diodes are not

recommended if signal levels must extend to ground.

High-Frequency Performance

In 50

Ω systems, signal response is reasonably flat up

to 50MHz (see Typical Operating Characteristics).

Above 20MHz, the on response has several minor

peaks that are highly layout dependent. The problem is

not turning the switch on, but turning it off. The off-state

switch acts like a capacitor and passes higher frequen-

cies with less attenuation. At 10MHz, off-isolation is

about -50dB in 50

Ω systems, becoming worse (approx-

imately 20dB per decade) as frequency increases.

Higher circuit impedances also degrade off-isolation.

Adjacent channel attenuation is about 3dB above that

of a bare IC socket and is entirely due to capacitive

coupling.

Chip Information

TRANSISTOR COUNT: 478

GND

V+

*INTERNAL PROTECTION DIODES

D2

EXTERNAL

BLOCKING DIODE

D1

EXTERNAL

BLOCKING DIODE

GND

V+

MAX4674

*

*

*

*

Figure 1. Overvoltage Protection Using External Blocking

Diodes