Low-Voltage 8:1 Mux/Dual 4:1 Mux/Triple SPDT/

Quad SPDT in UCSP Package

______________________________________________________________________________________

13

During normal operation, these (and other) reverse-

biased ESD diodes leak, forming the only current

drawn from V+ or V-.

Virtually all the analog leakage current comes from the

ESD diodes. Although the ESD diodes on a given sig-

nal pin are identical, and therefore fairly well balanced,

they are reverse biased differently. Each is biased by

either V+ or V- and the analog signal. This means their

leakages will vary as the signal varies. The difference in

the two diode leakages to the V+ and V- pins consti-

tutes the analog signal path leakage current. All analog

leakage current flows between each pin and one of the

supply terminals, not to the other switch terminal. This

is why both sides of a given switch can show leakage

currents of either the same or opposite polarity.

V+ and GND power the internal logic and logic-level

translators, and set both the input and output logic lim-

its. The logic-level translators convert the logic levels

into switched V+ and V- signals to drive the gates of

the analog signals. This drive signal is the only connec-

tion between the logic supplies (and signals) and the

analog supplies. V+ and V- have ESD-protection

diodes on GND.

Bipolar Supplies

The MAX4691/MAX4692/MAX4693 operate with bipolar

supplies between ±2V and ±5.5V. The V+ and V- sup-

plies need not be symmetrical, but their difference can-

not exceed the absolute maximum rating of +12V.

Single Supply

These devices operate from a single supply between +2V

and +11V when V- is connected to GND. All of the bipolar

precautions must be observed. At room temperature,

they operate with a single supply at near or below +2V,

although as supply voltage decreases, switch on-resis-

tance and switching times become very high.

Always bypass supplies with a 0.1µF capacitor.

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 devices.

Always sequence V+ on first, then V-, followed by the

logic inputs and by W, X, Y, Z. If power-supply

sequencing is not possible, add two small signal

diodes (D1, D2) in series with the supply pins for over-

voltage protection (Figure 1).

Adding diodes reduces the analog signal range to one

diode drop below V+ and one diode drop above V-, but

does not affect the devices’ low switch resistance and

low leakage characteristics. Device operation is

unchanged, and the difference between V+ and V-

should not exceed 12V. These protection diodes are

not recommended when using a single supply if signal

levels must extend to ground.

UCSP Reliability

The chip-scale package (UCSP) represents a unique

package that greatly reduces board space compared to

other packages. UCSP reliability is integrally linked to the

user’s assembly methods, circuit board material, and

usage environment. The user should closely review these

areas when considering a UCSP. Performance through

Operating Life Test and Moisture Resistance is equal to

conventional package technology as it is primarily deter-

mined by the wafer-fabrication process. However, this

form factor may not perform equally to a packaged prod-

uct through traditional mechanical reliability tests.

Mechanical stress performance is a greater considera-

tion for a UCSP. UCSP solder joint contact integrity

must be considered since the package is attached

through direct solder contact to the user’s PC board.

Testing done to characterize the UCSP reliability per-

formance shows that it is capable of performing reli-

ably through environmental stresses. Results of

environmental stress tests and additional usage data

and recommendations are detailed in the UCSP appli-

cation note, which can be found on Maxim’s website,

at www.maxim-ic.com.

( ) ARE FOR THE MAX4694 ONLY, REPLACE V- WITH GND.

MAX4691

MAX4692

MAX4693

MAX4694

COM

NO

V-

(GND)

V+

*INTERNAL PROTECTION DIODES

D2

D1

EXTERNAL BLOCKING DIODE

EXTERNAL BLOCKING DIODE

V- (GND )

V+

*

*

*

*

Figure 1. Overvoltage Protection