Integrated Device Technology Inc IDT74FST3125SO, IDT74FST3125Q Datasheet

The IDT logo is a registered trademark of Integrated Device Technology, Inc.

FEATURES:

• Bus switches provide zero delay paths

• Extended commercial range of –40°C to +85°C

• Low switch on-resistance:
FST3xxx – 5Ω

• TTL-compatible input and output levels

• ESD > 2000V per MIL-STD-883, Method 3015;
> 200V using machine model (C = 200pF, R = 0)

• Available in QSOP and SOIC

COMMERCIAL TEMPERATURE RANGE AUGUST 1996

1996 Integrated Device Technology, Inc. DSC-4668/-

1

IDT74FST3125

4-BIT BUS SWITCH

capability. Thus they generate little or no noise of their own
while providing a low resistance path for an external driver.
These devices connect input and output ports through an n­channel FET. When the gate-to-source junction of this FET is
adequately forward-biased the device conducts and the resis­tance between input and output ports is small. Without
adequate bias on the gate-to-source junction of the FET, the
FET is turned off, therefore with no VCC applied, the device
has hot insertion capability.

The low on-resistance and simplicity of the connection
between input and output ports reduces the delay in this path
to close to zero.

The FST3125 is a 4-bit TTL-compatible bus switch. The
xOE pins provide individual enable control for each of the four
bits.

DESCRIPTION:

The FST3125 belong to IDT's family of Bus switches. Bus
switch devices perform the function of connecting or isolating
two ports without providing any inherent current sink or source

1A 1Y

2A

2Y

3Y

4Y

3A

4A

4OE

2OE

1OE

3OE

FUNCTIONAL BLOCK DIAGRAM

PIN CONFIGURATION

PIN DESCRIPTION

3471 drw 01

3471 drw 02

3471 tbl 01

Pin Names I/O Description

1A-4A I/O Bus A
1Y-4Y I/O Bus B

NC — No Connect

1OE, 4

OE

I Bus Switch Enable (Active LOW)

Integrated Device Technology, Inc.

5

6
7
8

1
2

3
4

14

13
12

11
10

9

1A

1Y

NC

2A

2Y

GND

4A

4Y

3A
3Y

NC

Vcc

1OE

SO16-1
SO16-7

15

16

2OE

3OE

4OE

SOIC/QSOP

TOP VIEW

2

IDT74FST3125
4-BIT BUS SWITCH COMMERCIAL TEMPERATURE RANGE

FUNCTION TABLE

OE

OE

Y Description

H Hi-Z Disconnect

L A Connect

3471 tbl 03

DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE

Following Conditions Apply Unless Otherwise Specified:
Commercial: TA = –40°C to +85°C, VCC = 5.0V ±5%

ABSOLUTE MAXIMUM RATINGS

(1)

Symbol Description Max. Unit

VTERM

(2)

Terminal Voltage with Respect
to GND

–0.5 to +7.0 V

TSTG Storage Temperature –65 to +150 °C
IOUT Maximum Continuous Channel

Current

128 mA

NOTES:

1. Stresses greater than those listed under ABSOLUTE MAXIMUM RAT-

INGS may cause permanent damage to the device. This is a stress rating

only and functional operation of the device at these or any other conditions

above those indicated in the operational sections of this specification is not

implied. Exposure to absolute maximum rating condiitions for extended

periods may affect reliability.

2. V

CC, Control and Switch terminals.

3471 tbl 02

Symbol Parameter Conditions

(2)

Typ. Unit

CIN Control Input Capacitance 4 pF
CI/O

Switch Input/Output
Capacitance

Switch Off

pF

3471 tbl 04

CAPACITANCE

(1)

NOTES:

1. Capacitance is characterized but not tested

2. T

A = 25°C, f = 1MHz, VIN = 0V, VOUT = 0V

Symbol Parameter Test Conditions

(1)

Min. Typ.

(2)

Max. Unit

VIH Input HIGH Voltage Guaranteed Logic HIGH for Control Inputs 2.0 — — V
VIL Input LOW Voltage Guaranteed Logic LOW for Control Inputs — — 0.8 V
II H Input HIGH Current VCC = Max. VI = VCC ——±1µA
II L Input LOW Voltage VI = GND — — ±1
IOZH High Impedance Output Current VCC = Max. VO = VCC ——±1µA
IOZL (3-State Output pins) VO = GND — — ±1
IOS Short Circuit Current VCC = Max., VO = GND

(3)

— 300 — mA
VIK Clamp Diode Voltage VCC = Min., IIN = –18mA — –0.7 –1.2 V
RON Switch On Resistance

(4)

VCC = Min. VIN = 0.0V — 5 7 Ω
ION = 30mA
VCC = Min. VIN = 2.4V — 10 15 Ω
ION = 15mA

IOFF Input/Output Power Off Leakage VCC = 0V, VIN or VO ≤ 4.5V — — ±1 µA
ICC Quiescent Power Supply Current VCC = Max., VIN = GND or VCC — 0.1 3 µA

NOTES:

1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.

2. Typical values are at VCC = 5.0V, +25°C ambient.

3. Not more than one output should be tested at one time. Duration of the test should not exceed one second.

4. Measured by voltage drop between ports at indicated current through the switch.

3471 tbl 05