REV. C

ADG3257

–6–

D.U.T.

GENERATOR

S1

2

OPEN

GND

2

3

NOTES

OF THE PULSE GENERATOR.

Figure 1. Load Circuit

SWITCH INPUT

OUTPUT

0V

Figure 2. Propagation Delay

CONTROL INPUTS

0V

0V

0V

OUTPUT

LOW

OUTPUT

ENABLE

DISABLE

Figure 3. Select, Enable, and Disable Times

Table II. Switch S1 Condition

Test

S1

OPEN

2

GND

OPEN

Table III. Test Conditions

Symbol

10%

10%

Unit

500

500

Ω

300

300

mV

50

50

pF

APPLICATIONS

Mixed Voltage Operation, Level Translation

Bus switches can be used to provide a solution for mixed voltage

systems where interfacing bidirectionally between 5 V and 3 V

devices is required. To interface between 5 V and 3.3 V buses,

an external diode is placed in series with the 5 V power supply

as shown in Figure 4.

BE

3.3V TO 5V

3.3V TO 3.3V

5V MEMORY

5V I/O

3.3V CPU/DSP/

MICROPROCESSOR/

MEMORY

Figure 4. Level Translation Between 5 V and 3.3 V Devices

The diode drops the internal gate voltage down to 4.3 V.

The bus switch limits the voltage present on the output to

the output voltage would be limited to 3.3 V with a logic high.

3.3V

5V SUPPLY

0V

5V

SWITCH INPUT

Figure 5. Input Voltage to Output Voltage

Similarly, the device could be used to translate bidirectionally

between 3.3 V to 2.5 V systems. In this case, there is no need