High Speed, 3.3 V/5 V Quad 2:1 Mux/Demux
(4-Bit, 1 of 2) Bus Switch
ADG3257
Rev. E
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02914-001
FEATURES
100 ps propagation delay through the switch
2 Ω switches connect inputs to outputs
Data rates up to 933 Mbps
Single 3.3 V/5 V supply operation
Level translation operation
Ultralow quiescent supply current (1 nA typical)
3.5 ns switching
Switches remain in the off state when power is off
Standard 3257 type pinout
APPLICATIONS
Bus switching
Bus isolation
Level translation
Memory switching/interleaving
FUNCTIONAL BLOCK DIAGRAM
1
3
S
LOGIC
1B
1
1B
2
2B
1
2B
2
3B
1
3B
2
4B
1
4B
2
BE
Figure 1.
GENERAL DESCRIPTION
The ADG3257 is a CMOS bus switch comprised of four 2:1
multiplexers/demultiplexers with high impedance outputs. The
device is manufactured on a CMOS process. This provides low
power dissipation yet high switching speed and very low on
resistance, allowing the inputs to be connected to the outputs
without adding propagation delay or generating additional
ground bounce noise.
The ADG3257 operates from a single 3.3 V/5 V supply. The
control logic for each switch is shown in Table 1. These switches
are bidirectional when on. In the off state, signal levels are blocked
up to the supplies. When the power supply is off, the switches
remain in the off state, isolating Port A and Port B.
This bus switch is suited to both switching and level translation
applications. It can be used in applications requiring level trans-
lation from 3.3 V to 2.5 V when powered from 3.3 V. Additionally,
with a diode connected in series with 5 V V
DD
, the ADG3257
may also be used in applications requiring 5 V to 3.3 V level
translation.
Table 1. Truth Table
BE
S Function
H X Disable
L L A = B
1
L H A = B
2
PRODUCT HIGHLIGHTS
1. 0.1 ns propagation delay through switch.
2. 2 Ω switches connect inputs to outputs.
3. Bidirectional operation.
4. Ultralow power dissipation.
5. 16-lead QSOP package.
