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MAX4626EUK

0.5Ω, Low-Voltage, Single-Supply SPST Analog Switches

Maxim Integrated 

MAX4626/MAX4627/

MAX4628

0.5Ω, Low-Voltage, Single-Supply

SPST Analog Switches

Detailed Description

The MAX4626/MAX4627/MAX4628 are low-on-resistance

(RON), low-voltage, single-pole/single-throw (SPST)

analog switches that operate from a +1.8V to +5.5V

single supply. The MAX4626 is normally open (NO), and

the MAX4627 is normally closed (NC). The MAX4628 is

normally open (NO) and has two control inputs.

When powered from a +5V supply, their 0.5Ω RON allows

high continuous currents to be switched in a variety of

applications. In the event of an overcurrent condition,

these switches provide both current-limit and thermal-

shutdown protection.

Current-Limit Protection

The MAX4626/MAX4627/MAX4628 feature current-limit

protection circuitry. When the voltage drop across the on

switch reaches 0.6V (typ), the internal circuitry activates.

The current limit is not instantaneous, but rather

integrates over time so that current limiting will not activate

under momentary short-circuit conditions encountered

when the switch output charges a small 0.1μF capacitor.

For sustained overcurrent conditions, the switch turns off

(opens). The switch turns on after 5ms and, if the over-

load condition persists, the switch will cycle off and on

to produce a pulsed output. A direct short circuit will be

detected immediately, and the switch will pulse on for 1μs,

then remain off for 5ms.

POSITIVE SUPPLY

D1

V+

MAX4626

MAX4627

MAX4628

NO

COM

Vg

GND

D2

Applications Information

Logic Inputs

The MAX4626/MAX4627/MAX4628 logic inputs can be

driven up to +5.5V regardless of the supply voltage. For

example, with a +3.3V supply, IN or IN may be driven

low to 0V and high to 5.5V. Driving IN or IN Rail-to-Rail®

minimizes power consumption.

Analog Signal Levels

Analog signals that range over the entire supply voltage

(V+ to GND) can be passed with very little change in on-

resistance (see Typical Operating Characteristics). The

switches are bidirectional, so the NO, NC, and COM pins

can be used as either inputs or outputs.

Power-Supply Sequencing and

Overvoltage Protection

Caution: Do not exceed the absolute maximum rat-

ings; stresses beyond the listed ratings may cause

permanent damage to the devices.

Proper power-supply sequencing is recommended for

all CMOS devices. Always apply V+ before applying

analog signals, especially if the analog signal is not cur-

rent limited. If this sequencing is not possible, and if the

analog inputs are not current limited to <20mA, add a

small-signal diode (D1) as shown in Figure 1. If the ana-

log signal can dip below GND, add D2. Adding protection

diodes reduces the analog range to a diode drop (about

0.7V) below V+ (for D1), and a diode drop above ground

(for D2). On-resistance increases by a small amount at

low supply voltages. Maximum supply voltage (V+) must

not exceed +6V.

Adding protection diode D2 causes the logic thresholds to

be shifted relative to GND. TTL compatibility is not guar-

anteed when protection diode D2 is added.

Protection diodes D1 and D2 also protect against some

overvoltage situations. With Figure 1’s circuit, if the supply

voltage is below the absolute maximum rating, and if a

fault voltage up to the absolute maximum rating is applied

to an analog signal pin, no damage will result.

Figure 1. Overvoltage Protection Using Two External Blocking

Diodes

Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.

www.maximintegrated.com

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