Philips Semiconductors FAST Products
Product specification
9-Bit address/data Futurebus transceiver, ADT
74F8965/74F8966
FEATURES
• 9–bit transceiver (both directions)
• Drives heavily loaded backplanes with
equivalent load impedances down to
10 ohms
BTL offers low power consumption, low
ground bounce, EMI and crosstalk, low
capacitive loading, superior noise margin and
low propagation delays. This results in a high
bandwidth, reliable backplane.
• Guaranteed skew of less than 2ns
DESCRIPTION
The 74F8965 and 74F8966 are 9–bit
bidirectional latchable transceivers and are
intended to provide the electrical interface to
a high performance wired–OR bus. The B
port inverting drivers are low–capacitance
open collector with controlled ramp and are
designed to sink 100mA from 2 volts. The B
port inverting receivers have a precision band
gap references for improved noise margins.
The 74F8965 and 74F8966 A ports have TTL
3–state drivers and TTL receivers.
• High drive (100mA) open collector
drivers on B port
The B ports have standard BTL I/O with
• Reduced voltage swing (1V to 2V)
produces less noise and reduces
power consumption
100mA current sink capability. The B–to–A
path is a simple inverted buffered path. When
going from A–to–B the user may choose be-
tween a buffered path or a latching function.
• High speed operation enhances
performance of backplane buses and
facilitates incident wave switching
The 74F8966 also has an idle arbitrator/multi-
ple competitors output. The IAMC output
compares, using a wired–OR configuration,
the data on the bus to the latched data pres-
ented to the bus. If the bus data matches the
data presented by the 74F8966 then IAMC is
high. If the data doesn’t match then IAMC
goes low.
The B port interfaces to ’Backplane
Transceiver Logic’ (BTL). BTL features a
reduced (1V to 2V) voltage swing for lower
power consumption and a series diode on
the drivers to reduce capacitive loading.
• Compatible with IEEE 896 futurebus
standards and IEEE 1194 BTL stan-
dard
• Built–in precision band–gap reference
provides accurate receiver thresholds
and improved noise immunity
Incident wave switching is employed, there-
fore BTL propagation delays are short. Al-
though the voltage swing is much less for
BTL, so is its receiver threshold region,
therefore noise margins are excellent.
• Controlled output ramp and multiple
GND pins minimize ground bounce
• Glitch–free power up/power down
operation
TYPE
TYPICAL PROPAGATION DELAY
TYPICAL SUPPLY CURRENT( TOTAL)
74F8965
74F8966
3.5ns
3.5ns
80mA
80mA
ORDERING INFORMATION
ORDER CODE
DESCRIPTION
COMMERCIAL RANGE
V
CC
= 5V ±10%, T
= 0°C to +70°C
amb
44–pin PLCC
N74F8965A, N74F8966A
INPUT AND OUTPUT LOADING AND FAN OUT TABLE
74F (U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
PINS
DESCRIPTION
A0 – A8
B0 – B8
TTL data inputs
1.0/0.033
5.0/0.167
20µA/20µA
Data inputs with threshold circuitry
Output enable inputs
100µA/100µA
OEA, OEB0, OEB1
1.0/0.167
20µA/100µA
LS
Latch select (active low) (’F8965)
Idle arbitration request (active low) (’F8965)
Latch enable input (active low)
1.0/0.167
1.0/0.167
1.0/0.167
150/40
20µA/100µA
20µA/100µA
20µA/100µA
3mA/24mA
OC/100mA
IAREQ
LE
A0 – A8
B0 – B8
3–state TTL outputs
Open collector BTL outputs
OC/166.7
Idle arbitration/multiple competitors output (’F8966)
IAMC
OC/80
OC/48mA
Notes to input and output loading and fan out table
1. One (1.0) FAST unit load is defined as: 20µA in the high state and 0.6mA in the low state.
2. OC = Open collector.
1
December 19, 1990
853 1526 01320