Analog Signal Levels

Analog signals that range over the entire supply voltage

Typical Operating Characteristics). The bidirectional

switches allow NO_, NC_, and COM_ connections to be

used as either inputs or outputs.

Power-Supply Sequencing and

Overvoltage Protection

CAUTION: Do not exceed the absolute maximum

ratings. Stresses beyond the listed ratings can

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

current 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 analog signal can dip below GND, add D2. Adding

protection diodes reduces the analog signal range to a

diode drop (about 0.7V) below V+ (for D1), and to a

diode drop above ground (for D2). Leakage is unaffect-

ed by adding the diodes. On-resistance increases

slightly at low supply voltages. Maximum supply volt-

age (V+) must not exceed +11V.

Adding protection diodes causes the logic thresholds to

be shifted relative to the power-supply rails. The most

significant shift occurs when using low supply voltages

(+5V or less). With a +5V supply, TTL compatibility is not

guaranteed when protection diodes are added. Driving

IN1 and IN2 all the way to the supply rails (i.e., to a

diode drop higher than the V+ pin, or to a diode drop

lower than the GND pin) is always acceptable.

Protection diodes D1 and D2 also protect against some

overvoltage situations. Using the circuit in Figure 1, no

damage results if the supply voltage is below the

absolute maximum rating (+12V) and if a fault voltage

up to the absolute maximum rating (V+ + 0.3V) is

applied to an analog signal terminal.

UCSP Applications Information

For the latest application details on USCP construction,

dimensions, tape carrier information, printed circuit

board techniques, bump-pad layout, and recommend-

ed reflow temperature profile as well as the latest infor-

mation on reliability testing results, go to the Maxim

web site at www.maxim-ic.com/ucsp to find the

Application Note: UCSP—A Wafer-Level Chip-Scale

Package.

50

8

_______________________________________________________________________________________

MAX4731

MAX4732

MAX4733

NO_

COM_

GND

V+

*INTERNAL PROTECTION DIODES.

D2

D1

EXTERNAL BLOCKING DIODE

EXTERNAL BLOCKING DIODE

GND

V+

*

*

*

*

Figure 1. Overvoltage Protection Using External Blocking Diodes

Test Circuits/Timing Diagrams