Philips FB2033BB Datasheet

Philips Semiconductors Product specification

FB2033

8-bit latched/registered/pass-thru Futurebus+ universal interface transceiver

1995 May 25 853-1717 15279

FEATURES

•8-bit transceivers

•Latched, registered or straight through in either A to B or B to A

path

•Drives heavily loaded backplanes with equivalent load

impedances down to 10Ω.

•High drive 100mA BTL Open Collector drivers on B-port

•Allows incident wave switching in heavily loaded backplane buses

•Reduced BTL voltage swing produces less noise and reduces

power consumption

•Built-in precision band-gap reference provides accurate receiver

thresholds and improved noise immunity

•Compatible with IEEE Futurebus+ or proprietary BTL backplanes

•Each BTL driver has a dedicated Bus GND for a signal return

•Controlled output ramp and multiple GND pins minimize ground

bounce

•Glitch-free power up/power down operation

•Low I

current

•Tight output skew

•Supports live insertion

QUICK REFERENCE DATA

SYMBOL PARAMETER TYPICAL UNIT

PLH

PHL

Propagation delay AIn to Bn

3.0

PLH

PHL

Propagation delay Bn

to AOn

4.3

4.1

Output capacitance (B0 – Bn only) 6 pF

Output current (B0 – Bn only) 100 mA

AIn to Bn (outputs Low or High)

Supply current

Bn to AOn (outputs Low) 45

Bn to AOn (outputs High) 22

ORDERING INFORMATION

PACKAGES

COMMERCIAL RANGE

= 5V±10%; T

amb

= 0°C to +70°C

DRAWING

NUMBER

52-pin Plastic Quad Flat Pack (QFP) FB2033BB SOT379-1

NOTE: Thermal mounting or forced air is recommended

PIN CONFIGURATION

OEB0

52 51 50 49 48 47 46 45 44 43 42 41 40

39 38 37 36 35 34 33

32 31 30 29 28 27

1 2 3 4 5 6 7

9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 24 25 26

BUS GND B1 BUS GND B2 BUS GND B3

BUS GND B4 BUS GND B5 BUS GND

B6 BUS GND

LOGIC GND

AO1

AO2

AO3

LOOPBACK

AI4

AI5

AO6

AO7

AI1

AO0

OEA

LCBA

BIAS V

LGOIC GND

LCAB

8-Bit Universal Transceiver

FB2033

52-lead PQFP

BG GND

OEB1

LOGIC GND

AI2

AI3

AO4

AI6

LOGIC GND

AI7

SAB0

SAB1

BUS GND

AO5

AI0

SBA1

SBA0

BG V

SG00068

Philips Semiconductors Product specification

FB2033

8-bit latched/registered/pass-thru Futurebus+ universal interface transceiver

1995 May 25

DESCRIPTION

The FB2033 is an 8-bit transceiver featuring a split input (AI) and output (AO) bus on the TTL-level side.

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 pairs of mode select inputs (SBA0 and SBA1 for B-to-A, SAB0 and SAB1 for A-to-B). It can be configured as a buffer, a register, or a D-type latch.

When configured in the buffer mode, the inverse of the input data appears at the output port. In the flip-flop 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-High latch enables. Regardless of the mode, data is inverted from input to output.

Data flow in the B-to-A direction, regardless of the logic element selected, is further controlled by the Loopback input. When the Loopback input is High the output of the selected A-to-B logic element (not inverted) becomes the B-to-A input.

The 3-State AO port is enabled by asserting a High level on OEA. The B port has two output enables, OEB0 and OEB1

. Only when

OEB0 is High and OEB1

is Low is the output enabled. When either

OEB0 is Low or OEB1

is High, the B-port is inactive and is pulled to the level of the pull-up voltage. New data can be entered in the flip-flop and latched modes or can be retained while the associated outputs are in 3-State (AO 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 ensure 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 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

” clamp reduces inductive ringing effects

during a Low-to-High transition. The “V

” clamp is always active. The other clamp, the “trapped reflection” clamp, clamps out ringing below the BTL 0.5V V

level. This clamp remains active for

approximately 100ns after a High-to-Low transition. To support live insertion, OEB0 is held Low during power on/off

cycles to ensure glitch- free B port drivers. Proper bias for B port drivers during live insertion is provided by the BIAS V pin when at a 5V level while V

is Low. The BIAS V pin is a low current input which will reverse-bias the BTL driver series Schottky diode, and 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

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 very infrequent and impossible to trouble- shoot.

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.

PIN DESCRIPTION

SYMBOL PIN NUMBER TYPE NAME AND FUNCTION

AI0 – AI7 50, 52, 3, 5, 8, 10, 12, 15 Input Data inputs (TTL)

AO0 – AO7 51, 2, 4, 6, 9, 11, 14, 16 Output 3-State outputs (TTL)

B0 – B7 40, 38, 36, 34, 32, 30, 28, 26 I/O Data inputs/Open Collector outputs, High current drive (BTL)

OEB0 23 Input Enables the B outputs when High OEB1 24 Input Enables the B outputs when Low

OEA 43 Input Enables the AO outputs when High

BUS GND 39, 37, 35, 33, 31, 29, 27, 25 GND Bus ground (0V)

LOGIC GND 1, 13, 17, 49 GND Logic ground (0V)

18, 22, 48 Power Positive supply voltage

BIAS V 41 Power Live insertion pre-bias pin

BG V

44 Power Band Gap threshold voltage reference

BG GND 42 GND Band Gap threshold voltage reference ground

SABn 20, 21 Input Mode select from AI to B SBAn 45, 46 Input Mode select from B to AO LCAB 47 Input A-to-B clock/latch enable (transparent latch when High) LCBA 19 Input B-to-A clock/latch enable (transparent latch when High)

Loopback 7 Input Enables loopback function when High (from AIn to AOn)

Philips Semiconductors Product specification

FB2033

8-bit latched/registered/pass-thru Futurebus+ universal interface transceiver

1995 May 25

FUNCTION TABLE

INPUTS OUTPUTS

MODE

AIn Bn* OEB0 OEB1 OEA LCAB LCBA

SAB

SBA

AOn Bn

L — H L L X X LL XX Z H**

AIn to Bn thru mode

H — H L L X X LL XX Z L

L — H L L H X HX XX Z H**

AIn to Bn transparent latch

H — H L L H X HX XX Z L

l — H L L ↓ X HX XX Z H**

AIn to Bn latch and read

h — H L L ↓ X HX XX Z L L — H L L ↑ X LH XX Z H**

AIn to Bn register

H — H L L ↑ X LH XX Z L

Bn outputs latched and read (preconditioned latch)

X — H L L L X HX XX Z

latched

data

X L L H H X X XX LL H input

Bn to AOn thru mode

X H L H H X X XX LL L input X L L H H X H XX HX H input

Bn to AOn transparent latch

X H L H H X H XX HX L input X l L H H X ↓ XX HX H input

Bn to AOn latch and read

X h L H H X ↓ XX HX L input X L L H H X ↑ XX LH H input

Bn to AOn register

X H L H H X ↑ XX LH L input

AOn outputs latched and read (preconditioned latch)

X X L H H X L XX HX

latched

data

X X L X X X X XX XX X H**

Disable Bn outputs

X X X H X X X XX XX X H**

Disable AOn outputs X X X X L X X XX XX Z X

FUNCTION SELECT TABLE

MODE SELECTED SXX1 SXX0

Thru mode L L Register mode L H Latch mode H X

NOTES:

H = High voltage level L = Low voltage level h = High voltage level one set-up time prior to the High-to-Low LCXX transition l = Low voltage level one set-up time prior to the High-to-Low LCXX transition X = Don’t care Z = High-impedance (OFF) state — = Input not externally driven

↑ = Low-to-High transition ↓ = High-to-Low transition

H** = Goes to level of pull-up voltage Bn

* = Precaution should be taken to ensure B inputs do not float. If they do, they are equal to Low state.

NOTE: In Loopback mode (Loopback = High), AIn inputs are routed to the AOn outputs. The Bn

inputs are blocked out.

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