Datasheet CBT3857 Datasheet (Philips)

INTEGRATED CIRCUITS

CBT3857

10-bit bus switch with 10 kΩ pull-down
termination resistors

Product specification
Supersedes data of 1998 Dec 10

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1999 Sep 14

Philips Semiconductors Product specification

10-bit bus switch with 10 kΩ pull-down
termination resistors

FEA TURES

•Enable signal is SSTL_2 compatible

•Optimized for use in Double Data Rate (DDR) SDRAM

applications

•Flow-through architecture optimizes PCB layout

•Designed to be used with 200 Mbps

•Switch on resistance is designed to eliminate the need for series

resistor to DDR SDRAM

•Internal 10 kΩ pull-down resistors on B port

•Internal 50 kΩ pull-up resistor on output enable input

•Full DDR solution provided when used with SSTL16857 and

PCK857

•Latch-up protection exceeds 500 mA per JESD78

•ESD protection exceeds 2000 V HBM per JESD22-A114,

200 V MM per JESD22-A115 and 1000 V CDM per JESD22-C101

QUICK REFERENCE DATA

SYMBOL PARAMETER

C

t

PLH

t

PHL

C

OUT

I

CCZ

IN

Propagation delay
An to Yn

CL = 30 pF; VCC = 3.3 V 720 ps

Input capacitance VI = 0 V or V
Output capacitance Outputs disabled; VO = 0 V or V
Total supply current VCC = 3.6 V 1 mA

CBT3857

DESCRIPTION

This 10-bit bus switch is designed for 3 V to 3.6 V VCC operation
and SSTL_2 output enable (OE

When OE is LOW, the 10-bit bus switch is on and port A is
connected to port B. When OE
high-impedance state exists between the two ports.

The low on-state resistance of the switch allows connections to be
made with minimal propagation delay.

The CBT3857 is characterized for operation from 0°C to +85°C.

CONDITIONS

T

= 25°C; GND = 0 V

amb

CC

CC

) input levels.

is HIGH, the switch is open, and a

TYPICAL UNIT

2.8 pF

6.4 pF

ORDERING INFORMATION

PACKAGES TEMPERATURE RANGE ORDER CODE DWG NUMBER

24-Pin Plastic TSSOP Type I 0°C to +85°C CBT3857 PW SOT355–1

PIN CONFIGURATION

V

1

REF

2

A1

3

A2

4

A3

5

A4

6

A5

7

A6

8

A7

9

A8

10

A9

11

A10

12

GND

24

Vcc
OE

23
22

B1

21

B2

20

B3

19

B4

18

B5

17

B6

16

B7

15

B8
B9

14
13

B10

PIN DESCRIPTION

PIN NUMBER SYMBOL NAME AND FUNCTION

1 V

2, 3, 4, 5, 6,

7, 8, 9, 10, 11

REF

A1–A10 Inputs

Reference output voltage

12 GND Ground (V)

22, 21, 20, 19, 18,

17, 16, 15, 14, 13

B1–B10 Outputs

23 OE Output enable
24 V

CC

Positive supply voltage

FUNCTION TABLE

INPUT

OE

L A port = B port

H Disconnect

H = High voltage level
L = Low voltage level

FUNCTION

SA00516

1999 Sep 14 853–2168 22329

2

Philips Semiconductors Product specification

SYMBOL

PARAMETER

UNIT

10-bit bus switch with 10 kΩ pull-down
termination resistors

LOGIC DIAGRAM (POSITIVE LOGIC)

22

B1

R

INT

13

B10

R

INT

A10

V

OE

A1

REF

2

11

23

1

SW

SW

CBT3857

SIMPLIFIED SCHEMATIC, EACH FET SWITCH

BA

OE

SA00518

SA00517

ABSOLUTE MAXIMUM RA TINGS

SYMBOL

V

CC

I

IK

V

I

T

stg

V

I

DC supply voltage –0.5 to +4.6 V
DC input clamp current V
DC input voltage range (OE only)
Storage temperature range –65 to 150 °C
DC input voltage range (except OE)

PARAMETER CONDITIONS RATING UNIT

1, 3

< 0 –50 mA

2

2

I/O

VCC + 0.5 V

–0.5 to 4.6 V

NOTES:

1. Stresses beyond those listed may cause permanent damage to the device. These are stress ratings only and functional operation of the
device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to
absolute-maximum-rated conditions for extended periods may affect device reliability .

2. The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.

3. The package thermal impedance is calculated in accordance with JESD 51.

RECOMMENDED OPERATING CONDITIONS

LIMITS

Min Typ Max

V

V

REF

V
V
V
V

T

amb

NOTE:

1. All unused control inputs of the device must be held at V

DC supply voltage 3 3.3 3.6 V

CC

Reference voltage (0.38 x VCC) 1.15 1.25 1.35 V

V

+

AC high-level input voltage

IH

AC low-level Input voltage V

IL

DC high-level input voltage

IH

DC low-level Input voltage V

IL

REF

350 mV

V

REF

180 mV

– 350 mV V

REF

+

– 180 mV V

REF

Operating free-air temperature range 0 +85 °C

or GND to ensure proper device operation.

CC

V

V

1999 Sep 14

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Philips Semiconductors Product specification

IIInput leakage current

V

V

V

GND

2

SYMBOL

PARAMETER

FROM (INPUT)

TO (OUTPUT)

UNIT

10-bit bus switch with 10 kΩ pull-down

CBT3857

termination resistors

DC ELECTRICAL CHARACTERISTICS

LIMITS

T

SYMBOL PARAMETER TEST CONDITIONS

V

Input clamp voltage VCC = 3 V; II = –18 mA –1.2 V

IK

OE ±0.73 ±500 µA
A Port ±0.1 ±1 µA
B Port ±20 ±500 µA

V

REF

Ci

O(OFF)

p

I

CC

C

Quiescent supply current VCC = 3.6 V; IO = 0, VI = VCC or GND 0.7 1.5 mA
Control pins VI= 3 V or 0 2.8 pF

I

CC

= 3.6 V;

;

Power-off leakage current VO = 3 V or 0; OE = V

VCC = 3 V to 3.6 V; V

r

on

On-resistance

VCC = 3 V to 3.6 V; V

=

or

I

CC

CC

= 0.8 V; VB = 1.15 V 20 24 30

A

= 1.7 V; VB = 1.35 V 20 24 30

A

VCC = 3 V to 3.6 V; VI = 1.25 V; II = ±10 mA 20 24 30

2

r

off

Off-resistance VCC = 3 V to 3.6 V; VI = 1.65 V 1 MΩ

NOTES:

1. All typical values are at V

2. Measured by the voltage drop between the A and the B terminals at the indicated current through the switch. On–state resistance is

= 3.3 V, T

CC

amb

= 25°C

determined by the lowest voltage of the two (A or B) terminals.

= 0°C to +85°C

amb

Min Typ

±0.1 ±1 µA

6.4 pF

1

Max

UNIT

Ω

AC CHARACTERISTICS

VCC = +3.3 V ±0.3 V

Min Max

t

pd

t

en

t

dis

Propagation delay
enable OE A or B 1 3 ns
disable OE A or B 1 3 ns

NOTE:

1. The propagation delay is based on the RC time constant of the typical on–state resistance of the switch and a load capacitance, when driven
by an ideal voltage source (zero output impedance); 24 Ω × 30 pF.

BACK SIDE

FRONT SIDE

1

184/200-pin DDR SDRAM DIMM

SDRAM

SDRAM

SDRAM

CBT CBT CBT CBT CBT CBT CBT CBT CBT

SDRAM

SDRAM

SDRAM

SSTL16857 PCK857SSTL16857

A or B B or A 750 ps

SDRAM

SDRAM

SDRAM

SDRAM

SDRAM

SDRAM

SDRAM

SDRAM

SDRAM

SDRAM

SDRAM

CBT3857 (9)

SDRAM

1999 Sep 14

The PLL clock distribution device and SSTL registered drivers reduce
signal loads on the memory controller and prevent timing delays and
waveform distortions that would cause unreliable operation

4

SW00393

Philips Semiconductors Product specification

10-bit bus switch with 10 kΩ pull-down
termination resistors

AC WAVEFORMS

VM = 1.5 V, VIN = GND to 3.0 V

2.75 V

t

t

PHZ

PLZ

1.375V

t

PHL

V

REF

V

V

OL

OH

+ 0.15V

– 0.15V

0 V

V

V

SA00513

VIH (AC)

VIL (AC)

3.5V

V

OL

V

OH

0V

SA00514

INPUT

OUTPUT

1.375V

t

PLH

1.25V 1.25V

Waveform 1. Input (An) to Output (Yn) Propagation Delays

Output Control

(Low-level

enabling

Output

Waveform 1

S1 at 4.3 V

(see Note)

Output

Waveform 2

S1 at Open
(see Note) *

Note:

Waveform 1 is for an output with internal conditions such that
the output is low except when disabled by the output control.

Waveform 2 is for an output with internal conditions such that
the output is high except when disabled by the output control.

V

REF

t

PZL

1.25 V

t

PZH

1.25 V

* VIH = 3.0V with 25Ω input line impedance

Waveform 2. 3-State Output Enable and Disable Times

CBT3857

TEST CIRCUIT AND WAVEFORMS

From Output
Under Test

C

= 30 pF

L

OH

OL

DEFINITIONS

= Load capacitance includes jig and probe capacitance

C

L

500 Ω

500 Ω

Load Circuit

TEST S1

t

pd

t

PLZ/tPZL

t

PHZ/tPZH

open

4.3 V
GND

NOTES:

1. All input pulses are supplied by generators having the following
characteristics: PRR ≤ 10 MHz, Z

2. The outputs are measured one at a time with one transition per

= 50 Ω, tr ≤ 2.5 ns, tf ≤ 2.5 ns.

O

measurement.

4.3 V

S1

Open

GND

SA00515

1999 Sep 14

5

Philips Semiconductors Product specification

10-bit bus switch with 10 kΩ pull-down
termination resistors

TSSOP24: plastic thin shrink small outline package; 24 leads; body width 4.4 mm SOT355-1

CBT3857

1999 Sep 14

6

Philips Semiconductors Product specification

10-bit bus switch with 10 kΩ pull-down
termination resistors

NOTES

CBT3857

1999 Sep 14

7

Philips Semiconductors Product specification

10-bit bus switch with 10 kΩ pull-down
termination resistors

Data sheet status

Data sheet
status

Objective
specification

Preliminary
specification

Product
specification

Product
status

Development

Qualification

Production

Definition

This data sheet contains the design target or goal specifications for product development.
Specification may change in any manner without notice.

This data sheet contains preliminary data, and supplementary data will be published at a later date.
Philips Semiconductors reserves the right to make changes at any time without notice in order to
improve design and supply the best possible product.

This data sheet contains final specifications. Philips Semiconductors reserves the right to make
changes at any time without notice in order to improve design and supply the best possible product.

[1]

CBT3857

[1] Please consult the most recently issued datasheet before initiating or completing a design.

Definitions

Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For

detailed information see the relevant data sheet or data handbook.
Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one

or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or
at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended
periods may affect device reliability.

Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips
Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or
modification.

Disclaimers

Life support — These products are not designed for use in life support appliances, devices or systems where malfunction of these products can

reasonably be expected to result in personal injury . Philips Semiconductors customers using or selling these products for use in such applications
do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application.

Right to make changes — Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard
cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no
responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these
products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless
otherwise specified.

Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone [phone]

 Copyright Philips Electronics North America Corporation 1999

All rights reserved. Printed in U.S.A.

Date of release: 09-99

Document order number: 9397-750 -06413

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1999 Sep 14

8