16-Bit Registered Transceivers
CY74FCT16646T
CY74FCT162646T
SCCS060 - August 1994 - Revised March 2000
Data sheet acquired from Cypress Semiconductor Corporation.
Data sheet modified to remove devices not offered.
Copyright © 2000, Texas Instruments Incorporated
Features
FCT-E speed at 3.8 ns
Power-off disable outputs permits live insertion
Edge-rate control circuitry for significantly improved
noise characteristics
Typical output skew < 250 ps
ESD > 2000V
TSSOP (19.6-mil pitch) and SSOP (25-mil pitch)
packages
Industrial temperature range of 40˚C to +85˚C
•V
CC = 5V ± 10%
CY74FCT16646T Features:
64 mA sink current, 32 mA source current
Typical VOLP (ground bounce) <1.0V at VCC = 5V,
TA = 25˚C
CY74FCT162646T Features:
Balanced 24 mA output drivers
Reduced system switching noise
Typical VOLP (ground bounce) <0.6V at VCC = 5V,
TA= 25˚C
Functional Description
The CY74FCT16646T and CY74FCT162646T 16-bit
transceivers are three-state, D-type registers, and control
circuitry arranged for multiplexed transmission of data directly
from the input bus or from the internal registers. Data on the A
or B bus will be clocked into the registers as the appropriate
clock pin goes to a HIGH logic level. Output Enable (OE) and
direction pins (DIR) are provided to control the transceiver
function. In the transceiver mode, data present at the high
impedance port may be stored in either the A or B register, or
in both. The select controls can multiplex stored and real-time
(transparent mode) data. The direction control determines
which bus will receive data when the Output Enable (OE) is
ActiveLOW.In theisolation mode(OutputEnable(OE) HIGH),
A data may be stored in the B register and/or B data may be
stored in the A register. The output buffers are designed with
a power-off disable feature that allows live insertion of boards.
The CY74FCT16646T is ideally suited for driving
high-capacitance loads and low-impedance backplanes.
The CY74FCT162646T has 24-mA balanced output drivers
with current limiting resistors in the outputs. This reduces the
need for external terminating resistors and provides for
minimal undershoot and reduced ground bounce. The
CY74FCT162646T is ideal for driving transmission lines.
Logic Block Diagrams
FCT16646-1
C
D
1B1
C
D
1A1
TO7 OTHER CHANNELS
1SAB
1CLKAB
1CLKBA
1DIR
1SBA
1OE
B REG
A REG
C
D
2B1
C
D
2A1
2SAB
2CLKAB
2CLKBA
2DIR
2SBA
2OE
B REG
FCT16646-2
TO 7 OTHER CHANNELS
A REG
CY74FCT16646T
CY74FCT162646T
2
GND
1DIR
SSOP/TSSOP
Top View
1CLKAB
1SAB
1A1
1A2
1CLKBA
1SBA
1B1
1OE
GND
GND
VCC
1A3VCC
GND
1A4
1A5
1A6
1A7
1A8
2A1
2A2
2A3
2A4
GND
2A5
2A6
VCC
2A7
2A8
2SAB
2CLKAB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
GND
2DIR
1B2
1B3
1B4
1B5
1B6
1B7
1B8
2B1
2B2
2B3
GND
2B4
2B5
2B6
VCC
2B7
2B8
GND
2SBA
2CLKBA
2OE
FCT16646-3
Pin Configuration
Pin Description
Pin Names Description
A Data Register A Inputs
Data Register B Outputs
B Data Register B Inputs
Data Register A Outputs
CLKAB, CLKBA Clock Pulse Inputs
SAB, SBA Output Data Source Select Inputs
DIR Direction
OE Output Enable (Active LOW)
CY74FCT16646T
CY74FCT162646T
3
Function Table[1]
Inputs Data I/O[2] Function
OE DIR CLKAB CLKBA SAB SBA A B
H
HX
XH or L H or L X
XX
XInput Input Isolation
Store A and B Data
L
LL
LX
XX
H or L X
XL
HOutput Input Real Time B Data to A Bus
Stored B Data to A Bus
L
LH
HX
H or L X
XL
HX
XInput Output Real Time A Data to Bus
Stored A Data to B Bus
Notes:
1. H = HIGH Voltage Level. L = LOW Voltage Level. X = Don’t Care. = LOW-to-HIGH Transition
2. The data output functions may be enabled or disabled by various signals at the OE or DIR inputs. Data input functions are always enabled, i.e., data at the
bus pins will be stored on every LOW-to-HIGH transition on the clock inputs.
3. Cannot transfer data to A-bus and B-bus simultaneously.
BUS BBUS A
DIR
LOE
LCLKAB
XSAB
X
BUS BBUS A
DIR
H
L
X
OE
L
L
H
CLKAB
X
SAB
X
X
X
SBA
X
X
X
BUS BBUS A
DIR
HOE
LSAB
LSBA
X
BUS ABUS A
DIR
L
H
OE
L
L
SAB
X
H
SBA
H
X
Real-Time Transfer
BusB to BusA Real-Time Transfer
BusA to BusB
Storagefrom
A and/orB TransferStoredData
to A and/orB
CLKBA
XCLKAB
XCLKBA
X
SBA
L
CLKBA
XCLKAB
X
HorL
CLKBA
HorL
X
[3]
CY74FCT16646T
CY74FCT162646T
4
Maximum Ratings[4]
(Above which the useful life may be impaired. For user guide-
lines, not tested.)
Storage Temperature .....................Com’l 55°C to +125°C
Ambient Temperature with
Power Applied.................................Com’l 55°C to +125°C
DC Input Voltage .................................................0.5V to +7.0V
DC Output Voltage ..............................................−0.5V to +7.0V
DC Output Current
(Maximum Sink Current/Pin)...........................60 to +120 mA
Power Dissipation..........................................................1.0W
Static Discharge Voltage............................................>2001V
(per MIL-STD-883, Method 3015)
Operating Range
Range Ambient
Temperature VCC
Industrial 40°C to +85°C 5V ± 10%
Electrical Characteristics Over the Operating Range
Parameter Description Test Conditions Min. Typ.[5] Max. Unit
VIH Input HIGH Voltage 2.0 V
VIL Input LOW Voltage 0.8 V
VHInput Hysteresis[6] 100 mV
VIK Input Clamp Diode Voltage VCC=Min., IIN=18 mA 0.7 1.2 V
IIH Input HIGH Current VCC=Max., VI=VCC ±1µA
IIL Input LOW Current VCC=Max., VI=GND ±1µA
IOZH High Impedance Output Current
(Three-State Output pins) VCC=Max., VOUT=2.7V ±1µA
IOZL High Impedance Output Current
(Three-State Output pins) VCC=Max., VOUT=0.5V ±1µA
IOS Short Circuit Current[7] VCC=Max., VOUT=GND 80 140 200 mA
IOOutput Drive Current[7] VCC=Max., VOUT=2.5V 50 180 mA
IOFF Power-Off Disable VCC=0V, VOUT4.5V[9] ±1µA
Output Drive Characteristics for CY74FCT16646T
Parameter Description Test Conditions Min. Typ.[5] Max. Unit
VOH Output HIGH Voltage VCC=Min., IOH=3 mA 2.5 3.5 V
VCC=Min., IOH=15 mA 2.4 3.5 V
VCC=Min., IOH=32 mA 2.0 3.0 V
VOL Output LOW Voltage VCC=Min., IOL=64 mA 0.2 0.55 V
Output Drive Characteristics for CY74FCT162646T
Parameter Description Test Conditions Min. Typ.[5] Max. Unit
IODL Output LOW Current[7] VCC=5V, VIN=VIH or VIL, VOUT=1.5V 60 115 150 mA
IODH Output HIGH Current[7] VCC=5V, VIN=VIH or VIL, VOUT=1.5V 60 115 150 mA
VOH Output HIGH Voltage VCC=Min., IOH=24 mA 2.4 3.3 V
VOL Output LOW Voltage VCC=Min., IOL=24 mA 0.3 0.55 V
Notes:
4. Stresses greater than those listed under Maximum Ratings 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 conditions for extended periods may affect reliability.
5. Typical values are at VCC= 5.0V, TA= +25˚C ambient.
6. This parameter is specified but not tested.
7. Not more than one output should be shorted at a time. Duration of short should not exceed one second. The use of high-speed test apparatus and/or sample
and hold techniques are preferable in order to minimize internal chip heating and more accurately reflect operational values. Otherwise prolonged shorting of
a high output may raise the chip temperature well above normal and thereby cause invalid readings in other parametrics tests. In any sequence of parameter
tests, IOS tests should be performed last.
8. This parameter is measured at characterization but not tested.
9. Tested at +25˚C.
CY74FCT16646T
CY74FCT162646T
5
Capacitance (TA = +25˚C, f = 1.0 MHz)
Symbol Description[8] Conditions Typ. Max. Unit
CIN Input Capacitance VIN = 0V 4.5 6.0 pF
COUT Output Capacitance VOUT =0V 5.5 8.0 pF
Power Supply Characteristics
Parameter Description Test Conditions[10] Min. Typ.[5] Max. Unit
ICC Quiescent Power Supply Current VCC=Max. VIN<0.2V
VIN>VCC0.2V 5 500 µA
ICC Quiescent Power Supply Current
TTL Inputs HIGH VCC = Max.
VIN=3.4V[11] 0.5 1.5 mA
ICCD Dynamic Power Supply
Current[12] VCC=Max.
Outputs Open
DIR=OE=GND
One-Bit Toggling
50% Duty Cycle
VIN=VCC or
VIN=GND 75 120 µA/MHz
ICTotal Power Supply Current[13] VCC=Max.
Outputs Open
fo=10 MHz(CLKBA)
50% Duty Cycle
DIR=OE=GND
One-Bit Toggling
f1=5 MHz
50% Duty Cycle
VIN=VCC or
VIN=GND 0.8 1.7 mA
VIN=3.4V or
VIN=GND 1.3 3.2
VCC=Max.
Outputs Open
fo=10 MHz (CLKBA)
50% Duty Cycle
DIR=OE=GND
Sixteen-Bits Toggling
f1=2.5 MHz
50% Duty Cycle
VIN=VCC or
VIN=GND 3.8 6.5[14]
VIN=3.4V or
VIN=GND 8.3 20.0[14]
Notes:
10. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.
11. Per TTL driven input (VIN=3.4V); all other inputs at VCC or GND.
12. This parameter is not directly testable, but is derived for use in Total Power Supply calculations.
13. IC=I
QUIESCENT + IINPUTS + IDYNAMIC
IC=I
CC+ICCDHNT+ICCD(f0/2 + f1N1)
ICC = Quiescent Current with CMOS input levels
ICC = Power Supply Current for a TTL HIGH input (VIN=3.4V)
DH= Duty Cycle for TTL inputs HIGH
NT= Number of TTL inputs at DH
ICCD = Dynamic Current caused by an input transition pair (HLH or LHL)
f0= Clock frequency for registered devices, otherwise zero
f1= Input signal frequency
N1= Number of inputs changing at f1
All currents are in milliamps and all frequencies are in megahertz.
14. Values for these conditions are examples of the ICC formula. These limits are specified but not tested.
CY74FCT16646T
CY74FCT162646T
6
Switching Characteristics Over the Operating Range[15]
Parameter Description
CY74FCT16646T CY74FCT16646AT
CY74FCT162646AT
UnitMin. Max. Min. Max. Fig. No.[16]
tPLH
tPHL Propagation Delay
Bus to Bus 1.5 9.0 1.5 6.3 ns 1, 2
tPZH
tPZL Output Enable Time
DIR or OE to Bus 1.5 14.0 1.5 9.8 ns 1, 7, 8
tPHZ
tPLZ Output Disable Time
DIR or OE to Bus 1.5 9.0 1.5 6.3 ns 1, 7, 8
tPLH
tPHL Propagation Delay
Clock to Bus 1.5 9.0 1.5 6.3 ns 1, 5
tPLH
tPHL Propagation Delay
SBA or SAB to Bus 1.5 11.0 1.5 7.7 ns 1,5
tSU Set-Up Time HIGH or
LOW Bus to Clock 2.0 2.0 ns 4
tHHold Time HIGH or
LOW Bus to Clock 1.5 1.5 ns 4
tWClock Pulse Width
HIGH or LOW 5.0 5.0 ns 6
tSK(O) Output Skew[17] 0.5 0.5 ns
Parameter Description
CY74FCT16646CT
CY74FCT162646CT CY74FCT16646ET
CY74FCT162646ET
UnitMin. Max. Min. Max. Fig. No.[16]
tPLH
tPHL Propagation Delay
Bus to Bus 1.5 5.4 1.5 3.8 ns 1, 2
tPZH
tPZL Output Enable Time
DIR or OE to Bus 1.5 7.8 1.5 4.8 ns 1, 7, 8
tPHZ
tPLZ Output Disable Time
DIR or OE to Bus 1.5 6.3 1.5 4.0 ns 1, 7, 8
tPLH
tPHL Propagation Delay
Clock to Bus 1.5 5.7 1.5 3.8 ns 1, 5
tPLH
tPHL Propagation Delay
SBA or SAB to Bus 1.5 6.2 1.5 4.2 ns 1,5
tSU Set-Up Time HIGH or
LOW Bus to Clock 2.0 2.0 ns 4
tHHold Time HIGH or
LOW Bus to Clock 1.5 0.0 ns 4
tWClock Pulse Width
HIGH or LOW 5.0 3.0 ns 6
tSK(O) Output Skew[17] 0.5 0.5 ns
Notes:
15. Minimum limits are specified but not tested on Propagation Delays.
16. See “Parameter Measurement Information” in the General Information section.
17. Skew any two outputs of the same package switching in the same direction. This parameter is ensured by design.
CY74FCT16646T
CY74FCT162646T
7
Ordering Information CY74FCT16646
Speed
(ns) Ordering Code Package
Name Package Type Operating
Range
3.8 CY74FCT16646ETPVC/PVCT O56 56-Lead (300-Mil) SSOP Industrial
5.4 CY74FCT16646CTPVC/PVCT O56 56-Lead (300-Mil) SSOP Industrial
6.3 CY74FCT16646ATPVC/PVCT O56 56-Lead (300-Mil) SSOP Industrial
9.0 CY74FCT16646TPVC/PVCT O56 56-Lead (300-Mil) SSOP Industrial
Ordering Information CY74FCT162646
Speed
(ns) Ordering Code Package
Name Package Type Operating
Range
3.8 74FCT162646ETPACT Z56 56-Lead (240-Mil) TSSOP Industrial
CY74FCT162646ETPVC O56 56-Lead (300-Mil) SSOP
74FCT162646ETPVCT O56 56-Lead (300-Mil) SSOP
5.4 74FCT162646CTPACT Z56 56-Lead (240-Mil) TSSOP Industrial
CY74FCT162646CTPVC O56 56-Lead (300-Mil) SSOP
74FCT162646CTPVCT O56 56-Lead (300-Mil) SSOP
6.3 74FCT162646ATPACT Z56 56-Lead (240-Mil) TSSOP Industrial
CY74FCT162646ATPVC O56 56-Lead (300-Mil) SSOP
74FCT162646ATPVCT O56 56-Lead (300-Mil) SSOP
CY74FCT16646T
CY74FCT162646T
8
Package Diagrams
56-Lead Shrunk Small Outline Package O56
56-Lead Thin Shrunk Small Outline Package Z56
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