Philips
Semiconductors
CBT6820
20-bit bus switch with precharged outputs
and Schottky undershoot protection for
live insertion
Product specification
1999 Apr 05
INTEGRATED CIRCUITS
Philips Semiconductors
Product specification
CBT6820
20-bit bus switch with precharged outputs and
Schottky undershoot protection for live insertion
2
1999 Apr 05
8532152 21177
FEATURES
TTL compatible inputs and outputs
5
switch connection between two port A and port B
Thin shrink small outline (TSSOP)
Undershoot protection included to prevent shoot through level
changes
Bias voltage pre-charges the outputs to minimize signal distortion
during live insertion
DESCRIPTION
The CBT6820 provides twenty bits of high-speed TTL-compatible
bus switching. The low on-state resistance of the switch allows
bi-directional connections to be made while adding near-zero
propagation delay. The device also precharges the B port to a
user-selectable bias voltage (BIASV) to minimize live-insertion
noise.
The device is organized as two 10-bit switch with individual enable
(OE) input. When OE is low, the switch is on and port A is
connected to port B. When OE is high, the switch between port A
and port B is open and the B port is precharged to BIASV through
the equivalent of a 10-k
resistor.
Special clamp circuitry and Schottky diode clamps to ground are
used to prevent an under voltage on the A side (Vin
<
GND) from
causing the B side precharge voltage to drop below the ``1" state.
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
21
22
23
24
41
42
43
44
45
46
47
48
SA00520
1A1
1A2
1A3
1A4
1A5
1A6
GND
1A7
1A8
1A9
1A10
2A1
2A2
V
CC
2A3
GND
2A4
2A5
2A6
2A7
2A8
2A9
2A10
1OE
2OE
1B1
1B2
1B3
1B4
1B5
GND
1B6
1B7
1B8
1B9
1B10
2B1
2B2
2B3
GND
2B4
2B5
2B6
2B7
2B8
2B9
2B10
BIASV
QUICK REFERENCE DATA
SYMBOL
PARAMETER
CONDITIONS
T
amb
= 25
C; GND = 0V
TYPICAL
UNIT
t
PLH
/t
PHL
Propagation delay
An to Bn or Bn to An
C
L
= 50 pF, V
CC
= 5 V
0.25
ns
C
IN
Input capacitance
4.5
pF
C
I/O
Input/output capacitance
Outputs disabled; V
O
= 0 V or V
CC
9.5
pF
ORDERING INFORMATION
PACKAGES
TEMPERATURE RANGE
OUTSIDE NORTH AMERICA
NORTH AMERICA
DWG NUMBER
48-Pin Plastic TSSOP Type II
40
C to +85
C
CBT6820 DGG
CBT6820 DGG
SOT3621
Philips Semiconductors
Product specification
CBT6820
20-bit bus switch with precharged outputs and
Schottky undershoot protection for live insertion
1999 Apr 05
3
PIN DESCRIPTION
PIN NUMBER
SYMBOL
NAME AND FUNCTION
1
BIASV
Bias voltage
2, 3, 4, 5, 6,
7, 9, 10, 11,12
1A11A10
Port 1A1 to Port 1A10
8, 17, 32, 41
GND
Ground (V)
13, 14, 16, 18, 19,
20, 21, 22, 23, 24
2A12A10
Port 2A1 to Port 2A10
15
V
CC
Positive supply voltage
35, 34, 33, 31, 30,
29, 28, 27, 26, 25
2B12B10
Port 2B1 to Port 2B10
46, 45, 44, 43, 42,
40, 39, 38, 37, 36
1B11B10
Port 1B1 to Port 1B10
48, 47
1OE, 2OE
Switch enables
FUNCTION TABLE
OE
STATE
L
A Port = B Port
H
A Port = Z
H
B Port = BIASV
H = High voltage level
L
= Low voltage level
Z = High impedance "off " state
LOGIC SYMBOL
BIASV
xA1
xA10
xOE
SA00506
1
46, 35
36, 25
2, 13
12, 24
48, 47
where x = 1 2
xB1
xB10
ABSOLUTE MAXIMUM RATINGS
SYMBOL
PARAMETER
CONDITIONS
RATING
UNIT
V
CC
DC supply voltage
0.5 to +7.0
V
I
IK
DC clamp diode current
V
I
< 0
50
mA
V
I
DC input voltage
1
0.5 to +7.0
V
I
SW
DC continuous channel current
V
O
= 0 to V
CC
128
mA
V
BIASV
DC bias voltage
0.5 to +7.0
V
T
stg
Storage temperature range
65 to 150
C
JA
Plastic thin shrink small outline package
(TSSOP)
104
C/W
NOTE:
1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
RECOMMENDED OPERATING CONDITIONS
SYMBOL
PARAMETER
LIMITS
UNIT
SYMBOL
PARAMETER
Min
Max
UNIT
V
CC
DC supply voltage
4.0
5.5
V
BIASV
DC supply voltage
1.3
V
CC
V
V
IH
High-level input voltage (control pin)
2.0
V
V
IL
Low-level Input voltage (control pin)
0.8
V
T
amb
Operating free-air temperature range
40
+85
C
Philips Semiconductors
Product specification
CBT6820
20-bit bus switch with precharged outputs and
Schottky undershoot protection for live insertion
1999 Apr 05
4
DC ELECTRICAL CHARACTERISTICS
LIMITS
SYMBOL
PARAMETER
TEST CONDITIONS
T
amb
= 40
C to +85
C
UNIT
Min
Typ
1
Max
V
IK
Input clamp voltage
V
CC
= 4.5V; I
I
= 18mA
1.2
V
I
I
Input leakage current (control pin)
V
CC
= 5.5V; V
I
= GND or 5.5V
5
A
I
O
Output bias current (B pins)
V
CC
= 4.5V; BiasV = 2.4V; V
O
= 0, OE = V
CC
0.25
mA
I
CC
Quiescent supply current
V
CC
= 5.5V; I
O
= 0, V
I
= V
CC
or GND
2.5
mA
I
CC
Control pins
2
V
CC
= 5.5V, one input at 3.4V,
other inputs at V
CC
or GND
2.5
mA
C
I
Input capacitance per OE pin
V
I
= 3V or 0
4.5
pF
C
O(OFF)
Capacitance per port (OFF-state)
V
O
= 3V or 0; switch off
9.5
pF
3
V
CC
= 4.5V; V
I
= 0V; I
I
= 64mA
5
7
r
on
3
On-resistance
V
CC
= 4.5V; V
I
= 0V; I
I
= 30mA
5
7
V
CC
= 4.5V; V
I
= 2.4V; I
I
= 15mA
10
15
V
P
Pass voltage
V
IN
= V
CC
= 4.5V; I
out
= 100
A
3.4
3.6
3.9
V
I
USP
Undershoot static current
protection
4
V
CC
= 5.0V, V
Bias
= V
CC
I
B
= 5
A, V
B
3.0V
10
mA
NOTES:
1. All typical values are at VCC = 5V, TA = 25 C
2. This is the increase in supply current for each input that is at the specified TTL voltage level rather than V
CC
or GND
3. 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.
4. Force I
USP
, measure V
B
3V
Philips Semiconductors
Product specification
CBT6820
20-bit bus switch with precharged outputs and
Schottky undershoot protection for live insertion
1999 Apr 05
5
AC CHARACTERISTICS FOR V
CC
= 5.0V
0.5V RANGE
GND = 0V; t
r
= t
f
2.5ns; C
L
= 50pF.
LIMITS
SYMBOL
PARAMETER
WAVEFORM
T
amb
= 40 to +85
C
UNIT
MIN
TYP
1
MAX
t
pd
Propagation delay; An to Bn; Bn to An
2
1
0.25
ns
t
PZH
3-State output enable time
OE to An; OE to Bn; BIASV = GND
2
1.3
3.1
5.3
ns
t
PZL
3-State output enable time
OE to An; OE to Bn; BIASV = 3.0V
2
1.4
2.9
4.6
ns
t
PHZ
3-State output enable time
OE to An; OE to Bn; BIASV = GND
2
1.7
2.8
4.5
ns
t
PLZ
3-State output enable time
OE to An; OE to Bn; BIASV = 3.0V
2
2.8
4.4
6.6
ns
NOTE:
1. All typical values are measured at T
amb
= 25
C and V
CC
= 5.0V
2. Warranted but not production tested. The propagation delay is based on the RC time constant of the typical ON-state resistance of the
switch and a load capacitance of 50pF, when driven by an ideal voltage source (zero output impedance)
AC WAVEFORMS
V
M
= 1.5V, V
IN
= GND to 3.0V
INPUT
1.5V
OUTPUT
t
PLH
t
PHL
SA00028
1.5V
1.5V
1.5V
3 V
0 V
V
OH
V
OL
Waveform 1. Waveforms Showing the Input (An) to Output (Bn)
Propagation Delays
Output Control
(Low-level
enabling
1.5 V
t
PZH
t
PHZ
V
OH
V
OL
t
PZL
t
PLZ
3.5V
0V
V
OL
+ 0.3V
V
OH
0.3V
SA00029
1.5 V
1.5 V
1.5 V
0V
3V
Output
Waveform 1
S1 at 7 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)
Waveform 2. Waveforms Showing the 3-State Output Enable
and Disable Times
TEST CIRCUIT AND WAVEFORMS
C
L
= 50 pF
500
Load Circuit
DEFINITIONS
C
L
=
Load capacitance includes jig and probe capacitance;
see AC CHARACTERISTICS for value.
TEST
S1
t
pd
open
t
PLZ
/t
PZL
7 V
t
PHZ
/t
PZH
open
SA00012
500
From Output
Under Test
S1
7 V
Open
GND
NOTES:
1. All input pulses are supplied by generators having the following
characteristics: PRR
10MHz, 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
CBT6820
20bit bus switch with precharged outputs and
Schottky undershoot protection for live insertion
1999 Apr 05
6
TSSOP48:
plastic thin shrink small outline package; 48 leads; body width 6.1mm
SOT362-1
Philips Semiconductors
Product specification
CBT6820
20bit bus switch with precharged outputs and
Schottky undershoot protection for live insertion
1999 Apr 05
7
NOTES
Philips Semiconductors
Product specification
CBT6820
20bit bus switch with precharged outputs and
Schottky undershoot protection for live insertion
Philips Semiconductors and Philips Electronics North America Corporation reserve 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. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing
or modification.
LIFE SUPPORT APPLICATIONS
Philips Semiconductors and Philips Electronics North America Corporation Products are not designed for use in life support appliances, devices,
or systems where malfunction of a Philips Semiconductors and Philips Electronics North America Corporation Product can reasonably be expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
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.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 940883409
Telephone 800-234-7381
DEFINITIONS
Data Sheet Identification
Product Status
Definition
Objective Specification
Preliminary Specification
Product Specification
Formative or in Design
Preproduction Product
Full Production
This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.
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.
Philips Semiconductors and Philips Electronics North America Corporation
register eligible circuits under the Semiconductor Chip Protection Act.
Copyright Philips Electronics North America Corporation 1998
All rights reserved. Printed in U.S.A.
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