Philips
Semiconductors
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
Product specification
Supersedes data of 1998 Dec 10
1999 Sep 14
INTEGRATED CIRCUITS
Philips Semiconductors
Product specification
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
2
1999 Sep 14
8532168 22329
FEATURES
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 k
pull-down resistors on B port
Internal 50 k
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
DESCRIPTION
This 10-bit bus switch is designed for 3 V to 3.6 V V
CC
operation
and SSTL_2 output enable (OE) input levels.
When OE is LOW, the 10-bit bus switch is on and port A is
connected to port B. When OE is HIGH, the switch is open, and a
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.
QUICK REFERENCE DATA
SYMBOL
PARAMETER
CONDITIONS
T
amb
= 25
C; GND = 0 V
TYPICAL
UNIT
t
PLH
t
PHL
Propagation delay
An to Yn
C
L
= 30 pF; V
CC
= 3.3 V
720
ps
C
IN
Input capacitance
V
I
= 0 V or V
CC
2.8
pF
C
OUT
Output capacitance
Outputs disabled; V
O
= 0 V or V
CC
6.4
pF
I
CCZ
Total supply current
V
CC
= 3.6 V
1
mA
ORDERING INFORMATION
PACKAGES
TEMPERATURE RANGE
ORDER CODE
DWG NUMBER
24-Pin Plastic TSSOP Type I
0
C to +85
C
CBT3857 PW
SOT3551
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
GND
V
REF
Vcc
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
OE
SA00516
PIN DESCRIPTION
PIN NUMBER
SYMBOL
NAME AND FUNCTION
1
V
REF
Reference output voltage
2, 3, 4, 5, 6,
7, 8, 9, 10, 11
A1A10
Inputs
12
GND
Ground (V)
22, 21, 20, 19, 18,
17, 16, 15, 14, 13
B1B10
Outputs
23
OE
Output enable
24
V
CC
Positive supply voltage
FUNCTION TABLE
INPUT
OE
FUNCTION
L
A port = B port
H
Disconnect
H = High voltage level
L
= Low voltage level
Philips Semiconductors
Product specification
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
1999 Sep 14
3
LOGIC DIAGRAM (POSITIVE LOGIC)
SW
SW
B1
B10
R
INT
R
INT
A1
A10
2
11
23
1
OE
V
REF
22
13
SA00517
SIMPLIFIED SCHEMATIC, EACH FET SWITCH
B
A
OE
SA00518
ABSOLUTE MAXIMUM RATINGS
1, 3
SYMBOL
PARAMETER
CONDITIONS
RATING
UNIT
V
CC
DC supply voltage
0.5 to +4.6
V
I
IK
DC input clamp current
V
I/O
< 0
50
mA
V
I
DC input voltage range (OE only)
2
V
CC
+ 0.5
V
T
stg
Storage temperature range
65 to 150
C
V
I
DC input voltage range (except OE)
2
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
SYMBOL
PARAMETER
LIMITS
UNIT
SYMBOL
PARAMETER
Min
Typ
Max
UNIT
V
CC
DC supply voltage
3
3.3
3.6
V
V
REF
Reference voltage (0.38 x V
CC
)
1.15
1.25
1.35
V
V
IH
AC high-level input voltage
V
REF
+
350 mV
V
V
IL
AC low-level Input voltage
V
REF
350 mV
V
V
IH
DC high-level input voltage
V
REF
+
180 mV
V
V
IL
DC low-level Input voltage
V
REF
180 mV
V
T
amb
Operating free-air temperature range
0
+85
C
NOTE:
1. All unused control inputs of the device must be held at V
CC
or GND to ensure proper device operation.
Philips Semiconductors
Product specification
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
1999 Sep 14
4
DC ELECTRICAL CHARACTERISTICS
LIMITS
SYMBOL
PARAMETER
TEST CONDITIONS
T
amb
= 0
C to +85
C
UNIT
Min
Typ
1
Max
V
IK
Input clamp voltage
V
CC
= 3 V; I
I
= 18 mA
1.2
V
OE
0.73
500
A
I
Input leakage current
V
CC
= 3 6 V; V = V
CC
or GND
A Port
0.1
1
A
I
I
Input leakage current
V
CC
= 3.6 V; V
I
= V
CC
or GND
B Port
20
500
A
V
REF
0.1
1
A
I
CC
Quiescent supply current
V
CC
= 3.6 V; I
O
= 0, V
I
= V
CC
or GND
0.7
1.5
mA
C
I
Control pins
V
I
= 3 V or 0
2.8
pF
Ci
O(OFF)
Power-off leakage current
V
O
= 3 V or 0; OE = V
CC
6.4
pF
2
V
CC
= 3 V to 3.6 V; V
A
= 0.8 V; V
B
= 1.15 V
20
24
30
r
on
2
On-resistance
V
CC
= 3 V to 3.6 V; V
A
= 1.7 V; V
B
= 1.35 V
20
24
30
V
CC
= 3 V to 3.6 V; V
I
= 1.25 V; I
I
=
10 mA
20
24
30
r
off
2
Off-resistance
V
CC
= 3 V to 3.6 V; V
I
= 1.65 V
1
M
NOTES:
1. All typical values are at V
CC
= 3.3 V, T
amb
= 25
C
2. Measured by the voltage drop between the A and the B terminals at the indicated current through the switch. Onstate resistance is
determined by the lowest voltage of the two (A or B) terminals.
AC CHARACTERISTICS
SYMBOL
PARAMETER
FROM (INPUT)
TO (OUTPUT)
V
CC
= +3.3 V
0.3 V
UNIT
SYMBOL
PARAMETER
FROM (INPUT)
TO (OUTPUT)
Min
Max
UNIT
t
pd
Propagation delay
1
A or B
B or A
750
ps
t
en
enable
OE
A or B
1
3
ns
t
dis
disable
OE
A or B
1
3
ns
NOTE:
1. The propagation delay is based on the RC time constant of the typical onstate resistance of the switch and a load capacitance, when driven
by an ideal voltage source (zero output impedance); 24
30 pF.
184/200-pin DDR SDRAM DIMM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
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
SW00393
CBT3857 (9)
CBT
CBT
CBT
CBT
CBT
CBT
CBT
CBT
CBT
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SDRAM
SSTL16857
PCK857
SSTL16857
BACK SIDE
FRONT SIDE
Philips Semiconductors
Product specification
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
1999 Sep 14
5
AC WAVEFORMS
V
M
= 1.5 V, V
IN
= GND to 3.0 V
INPUT
1.375V
OUTPUT
t
PLH
t
PHL
1.375V
1.25V
1.25V
2.75 V
0 V
V
OH
V
OL
SA00513
Waveform 1. Input (An) to Output (Yn) Propagation Delays
Output Control
(Low-level
enabling
1.25 V
t
PZH
t
PHZ
V
OH
V
OL
t
PZL
t
PLZ
3.5V
0V
V
OL
+ 0.15V
V
OH
0.15V
1.25 V
V
REF
V
REF
V
IH
(AC)
Output
Waveform 1
S1 at 4.3 V
(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.
Output
Waveform 2
S1 at Open
(see Note) *
V
IL
(AC)
* V
IH
= 3.0V with 25
input line impedance
SA00514
Waveform 2. 3-State Output Enable and Disable Times
TEST CIRCUIT AND WAVEFORMS
C
L
= 30 pF
500
Load Circuit
DEFINITIONS
C
L
=
Load capacitance includes jig and probe capacitance
TEST
S1
t
pd
open
t
PLZ
/t
PZL
4.3 V
t
PHZ
/t
PZH
GND
500
From Output
Under Test
S1
4.3 V
Open
GND
SA00515
NOTES:
1. All input pulses are supplied by generators having the following
characteristics: PRR
10 MHz, Z
O
= 50
, t
r
2.5 ns, t
f
2.5 ns.
2. The outputs are measured one at a time with one transition per
measurement.
Philips Semiconductors
Product specification
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
1999 Sep 14
6
TSSOP24:
plastic thin shrink small outline package; 24 leads; body width 4.4 mm
SOT355-1
Philips Semiconductors
Product specification
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
1999 Sep 14
7
NOTES
Philips Semiconductors
Product specification
CBT3857
10-bit bus switch with 10 k
pull-down
termination resistors
1999 Sep 14
8
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 940883409
Telephone 800-234-7381
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
Philips
Semiconductors
Data sheet
status
Objective
specification
Preliminary
specification
Product
specification
Product
status
Development
Qualification
Production
Definition
[1]
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.
Data sheet status
[1]
Please consult the most recently issued datasheet before initiating or completing a design.
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