3.3V BTL 9-bit latched/registered/pass-thru
universal transceiver with 30Ω termination
PIN CONFIGURATION
CC
V
LOGIC GND
LOGIC GND
LOGIC GND
LOGIC GND
LOGIC GND
LOGIC GND
LOGIC GND
LOGIC GND
A1
A0
52 51 50 49 48 47 46 45 44 43 42 41 40
1
2
A2
3
4
A3
A4
A5
A6
A7
9-Bit latched/registered transceiver
5
6
7
8
9
10
11
12
13
14 15 16 17 18 19 20 21 22 23 24 25 26
A8
SEL1
LCBA
OEA
BIAS V
FBL22031
52-lead PQFP
CC
LCAB
BG V
BG GND
OEB1
OEB0
SEL0
TDO (option)
CC
TMS (option)
TCK (option)
V
B8
CC
V
TDI (option)
B0
BUS GND
39
38
37
36
35
34
33
32
31
30
29
28
27
B7
BUS GND
FBL22031
BUS GND
B1
BUS GND
B2
BUS GND
B3
BUS GND
B4
BUS GND
B5
BUS GND
B6
BUS GND
SG00091
DESCRIPTION
The TTL-level side (A port) has a common I/O. The common I/O,
open collector B port operates at BTL signal levels. The logic
element for data flow in each direction is controlled by two mode
select inputs (SEL0 and SEL1). A “00” configures latches in both
directions. A “10” configures thru mode in both directions. A “01”
configures register mode in both directions. A “11” configures
register mode in the A-to-B direction and latch mode in the B-to-A
direction.
When configured in the buffer mode, the inverse of the input data
appears at the output port. In the register mode, data is stored on
the rising edge of the appropriate clock input (LCAB or LCBA). In the
latch mode, clock pins serve as transparent-Low latch enables.
Regardless of the mode, data is inverted from input to output.
The 3-State A port is enabled by asserting a High level on OEA. The
B port has two output enables, OEB0 and OEB1
is High and OEB1
When either OEB0 is Low or OEB1
is Low is the output enabled.
is High, the B port is inactive
and is pulled to the level of the pullup voltage. New data can be
entered in the register and latched modes or can be retained while
the associated outputs are in 3-State (A port) or inactive (B port).
The B-port drivers are Low-capacitance open collectors with
controlled ramp and are designed to sink 100mA. Precision band
gap references on the B-port insure very good noise margins by
limiting the switching threshold to a narrow region centered at 1.55V .
The B-port interfaces to “Backplane Transceiver Logic” (see the
IEEE 1194.1 BTL standard). BTL features low power consumption
by reducing voltage swing (1V p-p, between 1V and 2V) and
reduced capacitive loading by placing an internal series diode on the
. Only when OEB0
drivers. BTL also provides incident wave switching, a necessity for
high performance backplanes.
Output clamps are provided on the BTL outputs to further reduce
switching noise. The “V
during a Low-to-High transition. The “V
The other clamp, the “trapped reflection” clamp, clamps out ringing
below the BTL 0.5V V
approximately 100ns after a High-to-Low transition.
” clamp reduces inductive ringing effects
OH
level. This clamp remains active for
OL
” clamp is always active.
OH
To support live insertion, OEB0 is held Low during power on/off
cycles to insure glitch- free B port drivers. Proper bias for B port
drivers during live insertion is provided by the BIAS V pin when at a
3.3V level while V
which will reverse-bias the BTL driver series Schottky diode, and
is Low. The BIAS V pin is a low current input
CC
also bias the B port output pins to a voltage between 1.62V and
2.1V. This bias function is in accordance with IEEE BTL Standard
1194.1. If live insertion is not a requirement, the BIAS V pin should
be tied to a V
CC
pin.
The LOGIC GND and BUS GND pins are isolated inside the
package to minimize noise coupling between the BTL and TTL
sides. These pins should be tied to a common ground external to the
package.
Each BTL driver has an associated BUS GND pin that acts as a
signal return path and these BUS GND pins are internally isolated
from each other. In the event of a ground return fault, a “hard” signal
failure occurs instead of a pattern dependent error that may be
infrequent and impossible to troubleshoot.
As with any high power device, thermal considerations are critical. It
is recommended that airflow (300Ifpm) and/or thermal mounting be
used to ensure proper junction temperature.
1998 Sep 04
3
Philips SemiconductorsProduct specification
3.3V BTL 9-bit latched/registered/pass-thru
universal transceiver with 30Ω termination
P ACKAGE THERMAL CHARACTERISTICS
PARAMETERCONDITION52-PIN PLASTIC QFP
θjaStill air80°C/W
θja300 Linear feet per minute air flow58°C/W
θjcThermally mounted on one side to heat sink20°C/W
BG GND19GNDBand Gap threshold voltage reference ground
SEL020InputMode select
SEL115InputMode select
LCAB18InputA to B clock/latch enable (transparent latch when Low)
LCBA16InputB to A clock/latch enable (transparent latch when Low)
TMS42InputTest Mode Select (optional, if not implemented then no connect)
TCK44InputTest Clock (optional, if not implemented then no connect)
TDI22InputTest Data In (optional, if not implemented then no connect)
TDO21OutputTest Data Out (optional, if not implemented then shorted to TDI)
40, 38, 36, 34, 32,
30, 28, 26, 24
25, 27, 29, 31, 33,
35, 37, 39, 41
23, 43, 49PowerPositive supply voltage
17PowerBand Gap threshold voltage reference
I/OData inputs/Open Collector outputs, High current drive (BTL)
GNDBus ground (0V)
FBL22031
1998 Sep 04
4
Philips SemiconductorsProduct specification
MODE
An to Bn thru mode
An to Bn transparent latch
An to Bn latch and read
An to Bn register
Bn to An thru mode
Bn to An transparent latch
Bn to An latch and read
Bn to An register
Disable Bn outputs
Latch mode (Bn to An)
3.3V BTL 9-bit latched/registered/pass-thru
universal transceiver with 30Ω termination
FUNCTION TABLE
INPUTSOUTPUTS
AnBn*OEB0 OEB1OEALCABLCBASEL0SEL1AnBn
L—HLLXXHLinputH**
H—HLLXXHLinputL
p
Bn outputs latched and read
(preconditioned latch)
p
An outputs latched and read
(preconditioned latch)
H=High voltage level
L=Low voltage level
l=Low voltage level one set-up time prior to the Low-to-High
LCXX transition
h=High voltage level one set-up time prior to the Low-to-High
LCXX transition
X=Don’t care
1998 Sep 04
MODE SELECTEDSEL0SEL1
Thru modeHL
Register mode (An to Bn)XH
Latch mode (An to Bn)LL
Register mode (Bn to An)LH
LL
HH
Z=High-impedance (OFF) state
— =Input not externally driven
↑=Low-to-High transition
H** =Goes to level of pull-up voltage
* =Precaution should be taken to ensure B inputs do not float.
Bn
If they do, they are equal to Low state.
Disable = OEB0 is Low or OEB1
5
is High.
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