Datasheet VS3257Q, VS32257Q Datasheet (Vaishali Semiconductor)

VS3257 / VS32257

A

A

(

)

Quad 2:1 Mux/Demux VSwitch

Applications

•= 5V to 3.3V translation in mixed-supply
environment

•= Hot-swap interface

•= Logic replacement

General Description

The VS3257 is a high-speed TT L–c ompatible Quad 2:1 multiplexer/dem ultiplex er . T he VS3257 c ontains four
mux/demux channels, with a com mon path c ontrol (S) and active low enable (/E). T he low ON resis tance of
the VS3257 allows inputs to be connected to outputs, without adding propagation delay and without
generating additional signal noise. The VS32257 has 25Ω resistors in series with the switches to reduce
ground-bounce noise and signal reflection.

The VS3257 and VS32257 mux/demux switches are function and pinout compatible with QS3257 and
CBT3257 switches. They enable 5V to 3.3V translation when used with an external diode in the power supply
line. In addition, the high off-isolation in the ‘disable’ mode makes VS3257 and VS32257 ideal interface
elements for hot-swap applications.

•= Memory bank, video, & audio
swtiching

•= Power conservation

Features

•= Enhanced N-FET with no DC path to VCC
or GND in normal operating signal voltage
range.

•= Low impedance bidirectional data flow:
5Ω (VS3257) and 25Ω (VS32257)

•= Pin-compatible with QS3257 and CBT3257
switches.

•= Near zero propagation delay

•= Break-before-make feature

•= TTL-compatible control signals

•= Undershoot clamp diodes on all switch and

control pins

•= ESD rating >2000V (Human Body Model)
or >200V (Machine Model)

•= Latch-up current >100mA

•= Available in 150-mil wide QSOP package

•= Zero added ground bounce or signal noise

Figure 1. Functional Block Diagram Figure 2. Pin Configuration

All Pins Top View

S

QSOP

/E

S

1

I0

2

A

I1

3

A

Y

4

A

I0

B

5

I1

B

6

Y

B

7
8

Y

Y

Y

Y

A

B

C

D

I0

I0

I1
I0

I1

I1
I0

I1

B
B

C
C
D

D

GND

16
15
14
13
12

11

10

V

CC

/E

I0

D

I1

D

Y

D

I0

C

I1

C

9

Y

C

2001-04-12 Page 1 MDSS-0009-01

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VS3257/VS32257

Table 1. Pin Description

Name I/O Description

I0X, I1X I/O Data Input or Output
S I Select Input
/E I Enable Input
YA - YD I/O Data Output or Input

Table 2. Function Table

Inputs Path Function

/E S
H X Hi Impedance Disable all switches
L L IOX <-> YX Select 0
L H I1X <-> YX Select 1

Table 3. Absolute Maximum Ratings

Supply Voltage to Ground………………………….…..-0.5V to +7.0V
DC Switch Voltage VS……………………….………….-0.5V to +7.0V

DC Input Voltage VIN………………………………… ...-0.5V to +7.0V
AC Input Voltage (Pulse Width < 20ns)……………….…………-3.0V
DC Output Sink Current per Switch Pin…………………...…..120 mA
Maximum Power Dissipation…………………………….…..0.5 Watts
Storage Temperature………………………………...-65oC to +150oC

Note ABSOLUTE MAXIMUM CONTINUOUS RATINGS are those values beyond which damage to the device may

occur. Exposure to these conditions or conditions beyond those indicated may adversely affect device reliability.
Correct functional operation while operating in the absolute maximum rated conditions is not implied.

Table 4. Capacitance

TA = 25oC, f = 1 MHz, VIN = 0V, V

OUT

= 0V

QSOP

Pins Operation Typ Max Unit

Control Inputs 4 5 pF
VSwitch Channels Demux 5 7 pF

(Switch OFF) Mux 7 8 pF

Note Capacitance is guaranteed, but not production tested. Total capacitance of a path, when the switch is closed, is

the sum of the switch terminal capacitances.

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VS3257/VS32257
Table 5. Recommended Operating Conditions

Symbol Parameter Conditions Min Typ Max Units

VCC Power supply voltage 4.5 5.5 V
VIL Low level input voltage -0.5 0.8 V
VIH High level input voltage 2.0 5.5 V
TA Operating free-air temperature -40 85

o

C

Note:

1. All unused control input s of the device must be held at Vcc or GND, to ensure proper device operation

Table 6. Electrical Characteristics Over Recommended Operating Free-air Temperature Range

Symbol Parameter Test Conditions Min Typ

Control Inputs -1.5 VIK Clamp Voltage
Switch I/O

VCC = Min, IIK = -18 mA

VIN = VCC = 5V, I

= 4.3V, VN = 5V,

V

CC

I

= -5µA

OUT

OUT

= -5µA

-1.5

3.7 3.9 4.1 VOH Logic High Voltage Switch I/O

3.0 3.3 3.6

(1)

Max Units

V

V

I

I

Input Leakage

Control Inputs VCC = Max, VI = VCC or GND 1

µA

Current

| Power OFF Leakage

OFF

Current

|IOZ| OFF State Leakage

Current

Switch I/O Drive

ODL

Current (Logic LOW)

Switch I/O Drive

ODH

Current (Logic HIGH)

RON Switch ON

Resistance

(2)

Control Inputs |
Switch I/O
Switch I/O VCC = Max, V

VCC = Min, VIN = 0,
V

= 0.4V

OUT

VCC = Min, VIN = VCC,
V

= 2.4V

OUT

= Min, VIN = 0,

V

CC

= 30mA

I

OUT

V

= 0,

CC

VI or VO = VCC or GND

= VCC,

I/O

CC

/E = V

VS3257 50 mA I
VS32257 mA
VS3257 -50 mA I
VS32257 mA
VS3257 5 7
VS32257 20 28 40

1

1

µA

µA

Ω
Ω

Notes:

1. Typical values are specifi ed at V

2. R

is measured by forcing specified current into the ‘output ’ node of the switch with the ‘input’ node of the switch at the the

ON

specified voltage

= 5.0V and TA = 25oC.

CC

Table 7. Power Supply Characteristics Over Recommended Operating Free-air Temperature Range

Symbol Parameter Test Conditions

I

Quiescent Power Supply Current VCC = Max, S, /E = VCC or GND, f = 0 1

CCQ

∆ICC

Q

Dynamic Power Supply Current

CCD

Power Supply Current per Input High
(Control Inputs)

(2)

= Max, VIN = 3.4V, f = 0 1.5 mA

V

CC

(3)

VCC = Max, Switch pins open,

Control Inputs toggling at 50% duty cycle

(1)

Max Units

µA

0.25 mA/MHz

Notes:

1. For conditions shown as Min or Max, use the appropriate values per Recommended Operating Conditions.

2. Per TTL-driven control input. All other control inputs at GND. Switch I /O pins do not contribute to ∆ICC.

3. This parameter represents the average DC current resulting from the switching of internal nodes of the device at a given
frequency. The switch I/O pins make insignificant contribution to the dynamic power supply c urrent of the device. This paramete r
is guaranteed, but not producti on t ested.

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VS3257/VS32257

Figure 3. VOLTAGE TRANSLATION

5

4

Vout
(V)

3

VCC = 4.3V

2

1

0

0

Vin (V)

3 2 1

4 5

Figure 5. Voltage Translation. Application

1N4148
or equivalent

5V

DEVICE

I/O

/E

VCC = 5V

VCC

VS3257
VS32257

Figure 4. VOH CHARACTERISTICS

VOH
Output Voltage
(V)

10K

I/O

4.5

4.0

3.5

3.0

2.5

2.0

4.75 5.25

4.5

VCC – Supply Voltage (V)

5.0

3.3V

DEVICE

TA = 85°C
TA = 25°C

TA = - 40°C

5.5

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VS3257/VS32257

Table 8. Switching Characteristics Over Operating Range

TA = -40oC to +85oC, VCC = 5.0V + 10%
C

= 50pF, R

LOAD

Symbol

t

, t

Data Propagation Delay

PLH

PHL

t

, t

Switch Turn-on Delay, S to YX, I0X, or I1X 0.5 5.2 0.5 6.2 ns

PZH

PZL

t

, t

Switch Turn-on Delay, /E to YX, I0X, or I1X 0.5 4.8 0.5 5.8 ns

PZH

PZL

t

, t

Switch Turn-off Delay

PLZ

PHZ

Notes:

1. See test circuit s and waveforms.

2. This parameter is the c al culated theoretical RC time constant of ON-state resistance of the switch and the specif i ed l oad
capacitance when driven by an ideal voltage sourc e (zero source impedance). This time-constant is on the order of 0. 25 ns for
VS3257 and 1.25 ns for VS32257. S i nce this time-constant is much smaller t han ri se/fall times of t ypical driving signals, it adds
very little propagation delay to the system.

3. This parameter is guaranteed, but not production tested.

= 500Ω unless otherwise stated.

LOAD

Description

(2,3)

through the switch 0.25 1.25 ns

(3)

, S or /E to Y

(1)

, I0X, or I1X 0.5 5.0 0.5 5.0 ns

X

VS3257

(3)

Min

Max

VS32257

(3)

Min

Max Units

Figure 6. AC Test Circuit and Switching Waveforms

AC Test Circuit Load Switch

t

S

1

7 V

Pulse

Generator

50

Ω

V

IN

DUT

C

V

L

OUT

500

450

Ω

R

L

Ω

50Ω=Coax to

Oscilloscope

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PLH

t

PLZ

t

PHZ

Input Conditions

Input voltage = 0 V to 3.0 V
t

= tf = 2.5ns (10% to 90%)

r

Position

TEST S1

, t

Open

PHL

, t

Closed

PZL

, t

Open

PZH

VS3257/VS32257

Switching Waveforms

3.0 V

Input

tPLH tPHL

Switch Output

1.5 V
0 V

V

OH

1.5 V

V

OL

Propagation Delay

3.0 V

Control Input

Switch Output

(Switch Input = 3.0 V)

Switch Output

(Switch Input = 0 V)

tPHZ

0.3 V

tPLZ

0.3 V

Switch ON Switch OFF

tPZH

tPZL

Switch ON

1.5 V
0 V

VOH

1.5 V
0 V

3.5 V

1.5 V
V

OL

Enable and Disable Times

Ordering Information

Part Number No. of Pins Package Temperature
VS3257Q 16 QSOP
VS32257Q 16 QSOP

-40°C to +85°C

-40°C to +85°C

2001-04-12 Page 6 MDSS-0009-01

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Vaishali Semic onductor  747 Camden Avenue, Suite C  Cam pbel l  CA 95008  P h. 408.377.6060  Fax [phone]