Rainbow Electronics MAX9395 - Manual (Page 6)

MAX9394/MAX9395
Detailed Description
The LVDS interface standard provides a signaling
method for point-to-point communication over a con-
trolled-impedance medium as defined by the ANSI
TIA/EIA-644 standard. LVDS utilizes a lower voltage
swing than other communication standards, achieving
higher data rates with reduced power consumption,
while reducing EMI emissions and system susceptibility
to noise.
The MAX9394/MAX9395 high-speed, low-power 2:1
multiplexers and 1:2 demultiplexers with loopback pro-
vide signal redundancy switching in telecom and stor-
age applications. These devices select one of two
remote signal sources for local input and buffer a single
local output signal to two remote receivers.
The multiplexer section (channel B) accepts two differen-
tial inputs and generates a single LVDS output. The
demultiplexer section (channel A) accepts a single differ-
ential input and generates two parallel LVDS outputs. The
MAX9394/MAX9395 feature a loopback mode that con-
nects the input of channel A to the output of channel B
and connects the selected input of channel B to the out-
puts of channel A. LB_SELA and LB_SELB provide inde-
pendent loopback control for each channel.
Three LVCMOS/LVTTL logic inputs control the internal
connections between inputs and outputs, one for the
multiplexer portion of channel B (BSEL), and the other
two for loopback control of channels A and B (LB_SELA
and LB_SELB). Independent enable inputs for each dif-
ferential output pair provide additional flexibility.
Input Fail-Safe
The differential inputs of the MAX9394/MAX9395 pos-
sess internal fail-safe protection. Fail-safe circuitry
forces the outputs to a differential-low condition for
undriven inputs or when the common-mode voltage
exceeds the specified range. The MAX9394 provides
high-level input fail-safe detection for LVDS, HSTL, and
other GND-referenced differential inputs. The MAX9395
provides low-level input fail-safe detection for LVPECL,
CML, and other V
CC -referenced differential inputs.
Select Function
BSEL selects the differential input pair to transmit
through OUTB (OUTB) for LB_SELB = GND or through
OUTA_ (OUTA_) for LB_SELA = V
CC . LB_SEL_ controls
the loopback function for each channel. Connect
LB_SEL_ to GND to select the normal inputs for each
channel. Connect LB_SEL_ to V
CC to enable the loop-
2:1 Multiplexers and 1:2 Demultiplexers with
Loopback
6 _______________________________________________________________________________________
Pin Description (continued)
PIN
TQFP QFN
NAME FUNCTION
21 19 ENA0
Channel A0 Output Enable. Drive ENA0 high to enable the A0 LVDS outputs. An
internal 435k
Ω resistor to GND pulls ENA0 low when unconnected.
22 20 OUTA0
Channel A0 LVDS Inverting Output. Connect a 100 Ω termination resistor between
OUTA0 and OUTA0 at the receiver inputs to ensure proper operation.
23 21 OUTA0
Channel A0 LVDS Noninverting Output. Connect a 100 Ω termination resistor between
OUTA0 and OUTA0 at the receiver inputs to ensure proper operation.
26 24 INA
LVDS/HSTL (MAX9394) or LVPECL/CML (MAX9395) Noninverting Input. An internal
128k
Ω pullup resistor to V
CC pulls the input high when unconnected (MAX9394). An
internal 68k Ω resistor to GND pulls the input low when unconnected (MAX9395).
27 25 INA
LVDS/HSTL (MAX9394) or LVPECL/CML (MAX9395) Inverting Input. An internal
128k
Ω pullup resistor to V
CC pulls the input high when unconnected (MAX9394). An
internal 68k Ω resistor to GND pulls the input low when unconnected (MAX9395).
28 26 LB_SELA
Loopback Select for Channel A Output. Connect LB_SELA to GND or leave
unconnected to reproduce the INA (INA) differential inputs at OUTA_ (OUTA_).
Connect LB_SELA to V
CC to loop back the INB_ (INB_) differential inputs to OUTA_
(OUTA_). An internal 435k Ω resistor to GND pulls LB_SELA low when unconnected.
— — EP Exposed Paddle. Connect to GND for optimal thermal and EMI characteristics.