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General Description

The MAX9157 is a quad bus LVDS (BLVDS) transceiver

for heavily loaded, half-duplex multipoint buses. Small

32-pin QFN and TQFP packages and flow-through

pinouts allow the transceiver to be placed near the con-

nector for the shortest possible stub length. The

MAX9157 drives LVDS levels into a 27Ω load (double

terminated, heavily loaded LVDS bus) at up to

200Mbps. An input fail-safe circuit ensures the receiver

output is high when the differential inputs are open, or

undriven and shorted, or undriven and terminated. The

MAX9157 differential inputs feature 52mV hysteresis for

greater immunity to bus noise and reflections. The

MAX9157 operates from a single 3.3V supply, consum-

ing 80.9mA supply current with drivers enabled, and

22.7mA with drivers disabled.

The MAX9157’s high-impedance I/Os (except for

receiver outputs) when V

= 0 or open, combined

with glitch-free power-up and power-down, allow hot

swapping of cards in multicard bus systems; 7.2pF

(max) BLVDS I/O capacitances minimize bus loading.

The MAX9157 is offered in 5mm ✕ 5mm 32-pin QFN and

TQFP packages. The MAX9157 is fully specified for the

-40°C to +85°C extended temperature range. Refer to

the MAX9129 data sheet for a quad BLVDS driver, ideal

for dual multipoint full-duplex buses.

Applications

Features

♦ 32-TQFP and Space-Saving 32-QFN Packages

♦ 52mV LVDS Input Hysteresis

♦ 1ns (min) Transition Time (0% to 100%) Minimizes

Reflections

♦ Guaranteed 7.2pF (max) Bus Load Capacitance

♦ Glitch-Free Power-Up and Power-Down

♦ Hot-Swappable, High-Impedance I/O with V

= 0

or Open

♦ Guaranteed 200Mbps Driver Data Rate

♦ Fail-Safe Circuit

♦ Flow-Through Pinout

MAX9157

Quad Bus LVDS Transceiver

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

CARD 1 CARD 15 CARD 16

1in CARD

SPACING

Rt = 54Ω Rt = 54Ω

MAX9157

Typical Operating Circuit

19-2287; Rev 0; 1/02

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Pin Configurations appear at end of data sheet.

Functional Diagram appears at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX9157EGJ -40°C to +85°C 32 QFN (5mm

✕ 5mm)

MAX9157EHJ -40°C to +85°C 32 TQFP (5mm ✕ 5mm)

Add/Drop Muxes

Digital Cross-Connects

Network

Switches/Routers

Cellular Phone Base

Stations

DSLAMs

Multipoint Buses

Summary of content (16 pages)

PAGE 1
9-2287; Rev 0; 1/02 Quad Bus LVDS Transceiver The MAX9157’s high-impedance I/Os (except for receiver outputs) when VCC = 0 or open, combined with glitch-free power-up and power-down, allow hot swapping of cards in multicard bus systems; 7.2pF (max) BLVDS I/O capacitances minimize bus loading. The MAX9157 is offered in 5mm ✕ 5mm 32-pin QFN and TQFP packages. The MAX9157 is fully specified for the -40°C to +85°C extended temperature range.
PAGE 2
MAX9157 Quad Bus LVDS Transceiver ABSOLUTE MAXIMUM RATINGS VCC, AVCC to GND................................................-0.3V to +4.0V DO_+/RIN_+, DO_-/RIN_-, to GND .......................-0.3V to +4.0V DIN_, DE_, RE_ to GND.........................................-0.3V to +4.0V RO_ to GND................................................-0.3V to (VCC + 0.3V) AGND to GND .......................................................-0.3V to +0.3V Short-Circuit Duration (DO_+/RIN_+, DO_-/RIN_-) ....
PAGE 3
Quad Bus LVDS Transceiver (VCC = 3.0V to 3.6V, RL = 27Ω ±1%, differential input voltage |VID| = 0.1V to VCC, input common-mode voltage VCM = 0.05V to 2.4V, input voltage range = 0 to VCC, DE_ = high, RE_ = low, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = 3.3V, |VID| = 0.2V, VCM = 1.2V, and TA = +25°C.
PAGE 4
MAX9157 Quad Bus LVDS Transceiver AC ELECTRICAL CHARACTERISTICS (VCC = 3.0V to 3.6V, RL = 27Ω ±1%, differential input voltage |VID| = 0.2V to VCC, input frequency to LVDS inputs = 85MHz, input frequency to LVCMOS/LVTTL inputs = 100MHz, LVCMOS/LVTTL inputs = 0 to 3V with 2ns (10% to 90%) transition times. Differential input voltage transition time = 1ns (20% to 80%). Input common-mode voltage VCM = 1.2V to 1.8V, DE_ = high, RE_ = low, TA = -40°C to +85°C, unless otherwise noted.
PAGE 5
Quad Bus LVDS Transceiver (VCC = 3.0V to 3.6V, RL = 27Ω ±1%, differential input voltage |VID| = 0.2V to VCC, input frequency to LVDS inputs = 85MHz, input frequency to LVCMOS/LVTTL inputs = 100MHz, LVCMOS/LVTTL inputs = 0 to 3V with 2ns (10% to 90%) transition times. Differential input voltage transition time = 1ns (20% to 80%). Input common-mode voltage VCM = 1.2V to 1.8V, DE_ = high, RE_ = low, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = 3.3V, |VID| = 0.2V, VCM = 1.
PAGE 6
Typical Operating Characteristics (continued) (VCC = 3.3V, RL = 27Ω, driver CL = 10pF, receiver CL = 15pF, |VID| = 200mV, VCM = 1.2V, fIN = 20MHz, TA = +25°C, unless otherwise noted.) DRIVER TRANSITION TIME vs. LOAD CAPACITANCE DRIVER TRANSITION TIME vs. TEMPERATURE 1.2 tTHL tTLH 1.1 MAX9157 toc05 1.3 DRIVER TRANSITION TIME (ns) MAX9157 toc04 DRIVER TRANSITION TIME (ns) 1.3 1.2 tTHL 1.1 tTLH 1.0 0.9 0.8 1.0 0.7 5 10 15 20 25 -15 10 35 60 TEMPERATURE (°C) DRIVER TRANSITION TIME vs.
PAGE 7
Quad Bus LVDS Transceiver PIN NAME FUNCTION 1, 2, 22, 23, 24 N.C. No Connection. Not internally connected. 3 VCC Digital Power Supply 4, 21 GND Digital Ground 5 RE34 Receiver Channels 3 and 4 Enable (Enable Low). Drive RE34 low to enable receiver channels 3 and 4. 6 DE34 Driver Channels 3 and 4 Enable (Enable High). Drive DE34 high to enable driver channels 3 and 4.
PAGE 8
MAX9157 Quad Bus LVDS Transceiver Detailed Description The MAX9157 is a four-channel, 200Mbps, 3.3V BLVDS transceiver in 32-lead TQFP and QFN packages, ideal for driving heavily loaded multipoint buses, typically 16 to 20 cards plugged into a backplane. The MAX9157 receivers accept a differential input and have a fail-safe input circuit. The devices detect differential signals as low as 100mV and as high as VCC. The MAX9157 driver outputs use a current-steering configuration to generate a 9.
PAGE 9
Quad Bus LVDS Transceiver The MAX9157 driver outputs are current-source drivers and drive larger differential signal levels into loads lighter than 27Ω and smaller levels into loads heavier than 27Ω (see Typical Operating Characteristics curves). To keep loading from reducing bus impedance below the rated 27Ω load, PC board traces can be designed for higher unloaded characteristic impedance.
PAGE 10
Table 3. Receiver Mode OUTPUTS VID = (VDO_+/RIN_+) - (VDO_-/RIN_-) L VID < -100mV L L VID > 100mV H Fail-safe operation guaranteed when DO_+/RIN_+ and DO_-/RIN_- are open, undriven and shorted, or undriven and parallel terminated L H X RO_ Board Layout H Z A four-layer PC board that provides separate power, ground, input, and output signals is recommended. Keep the LVTTL/LVCMOS and BLVDS signals separated to prevent coupling. Table 4.
PAGE 11
Quad Bus LVDS Transceiver DIN_ 50% 50% tPLHD tPHLD CL 0 DO_+/RIN_+ RIN_- VOH 0 DIFFERENTIAL VCC 0 DIN_ RL/2 GND RIN_+ VOL DE_ +1.2V GENERATOR 80% 80% 0 VOD 50Ω 0 VOD = (VDO_+/RIN_+ - VDO_-/RIN_-) 20% RL/2 tTLH DO_-/RIN_1/4 MAX9157 CL 20% tTHL Figure 5. Driver High-Impedance Delay Test Circuit Figure 4. Driver Propagation Delay and Transition Time Waveforms VCC DE_ 50% 50% 0 tPZH tPHZ D0_+/RIN_+ WHEN DIN_ = VCC DO_-/RIN_- WHEN DIN_ = 0 VOH 50% 50% 1.2V 1.
PAGE 12
MAX9157 Quad Bus LVDS Transceiver DO_-/RIN_VID VCM VCM DO_+/RIN_+ tPLHD tPHLD VOH 80% 80% 50% 50% 20% 20% RO_ tTLH VOL tTHL Figure 8. Receiver Transition Time and Propagation Delay Timing Diagram VCC S1 RL DO_+/RIN_+ RO_ DO_-/RIN_GENERATOR CL RE_ 50Ω 1/4 MAX9157 CL INCLUDES LOAD AND TEST JIG CAPACITANCE. S1 = VCC FOR tPZL AND tPLZ MEASUREMENTS. S1 = GND FOR tPZH AND tPHZ MEASUREMENTS. Figure 9.
PAGE 13
Quad Bus LVDS Transceiver Pin Configurations DIN3 RO2 DIN2 RO1 DIN1 26 25 N.C. 1 24 N.C. N.C. 2 23 N.C. VCC 3 22 N.C.
PAGE 14
Quad Bus LVDS Transceiver MAX9157 Package Information 14 ______________________________________________________________________________________
PAGE 15
Quad Bus LVDS Transceiver ______________________________________________________________________________________ 15 MAX9157 Package Information (continued)
PAGE 16
Quad Bus LVDS Transceiver 32L TQFP, 5x5x01.0.EPS MAX9157 Package Information (continued) Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.