Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsInterface ICsInterface IC - analogue switches TQFN 32 EP

General Description

The MAX4885 integrates high-bandwidth analog

switches and level-translating buffers to implement a

complete 1:2 or 2:1 multiplexer for VGA signals. The

device provides switching for RGB, display data chan-

nel (DDC), and horizontal and vertical synchronization

(HSYNC, VSYNC) signals. A low-noise charge pump

with internal capacitors provides a boosted gate-drive

voltage to improve performance of the RGB switches.

In the 1:2 multiplexer mode, HSYNC/VSYNC inputs fea-

ture level-shifting buffers to support low-voltage CMOS

or standard TTL-compatible graphics controllers. In the

2:1 multiplexer mode, the output buffers for the

HSYNC/VSYNC inputs are disabled, allowing bidirec-

tional signaling. In both modes, DDC signals are volt-

age-clamped to an external voltage to provide level

translation and protection. The MAX4885 features a

5µA shutdown mode and is ESD protected to ±8kV

Human Body Model (HBM) on externally routed pins.

The MAX4885 is specified over the extended (-40°C to

+85°C) temperature range, and is available in the 32-

pin, 5mm x 5mm TQFN package.

Applications

Notebook Computers

Digital Projectors

Computer Monitors

Servers

KVM Switches

Features

♦ +5V Single-Supply Operation

♦ Programmable Voltage Clamp for Open-Drain

DDC Signals

♦ Low 5Ω (typ) On-Resistance (R, G, B Signals)

♦ Low 13pF (typ) On-Capacitance (R, G, B Signals)

♦ Break-Before-Make Switching Protects Against

Circuit Shorts

♦ ±8kV HBM ESD Protection on Externally Routed

Pins

♦ Low 300µA Supply Current (Lower than 1µA with

Charge Pump Disabled)

♦ Space-Saving, Lead-Free, 32-Pin (5mm x 5mm)

TQFN Package

MAX4885

Complete VGA 1:2 or 2:1 Multiplexer

________________________________________________________________ Maxim Integrated Products 1

19-0554; Rev 0; 5/06

EVALUATION KIT

AVAILABLE

MAX4885

TQFN

TOP VIEW

DDCA0

V+

GND

DDCA1

4567

2324 22 20 19 18

GND

V+

DDCB2

DDCA2

GND

V+

SEL

DDCB1

DDCB0

*EXPOSED PADDLE CONNECTED TO GND

*EP

Pin Configuration

Ordering Information

GRAPHICS

CONTROLLER

V+

GND

+3.3V

+5V

SEL

R0, B0, G0

H0, V0

DDCA0, DDCB0

0.1μF

VGA

PORT 1

VGA

PORT 2

R2, G2, B2

H2, V2

DDCA2, DDCB2

R1, G1, B1

H1, V1

DDCA1, DDCB1

DOCKING

STATION

MAX4885

Typical Operating Circuit

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX4885ETJ+

-40°C to +85°C

32 TQFN-EP*

T3255-4

*EP = Exposed pad.

+Denotes lead-free package.

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim's website at www.maxim-ic.com.

Summary of content (13 pages)

PAGE 1
9-0554; Rev 0; 5/06 KIT ATION EVALU LE B A IL A AV Complete VGA 1:2 or 2:1 Multiplexer The MAX4885 integrates high-bandwidth analog switches and level-translating buffers to implement a complete 1:2 or 2:1 multiplexer for VGA signals. The device provides switching for RGB, display data channel (DDC), and horizontal and vertical synchronization (HSYNC, VSYNC) signals. A low-noise charge pump with internal capacitors provides a boosted gate-drive voltage to improve performance of the RGB switches.
PAGE 2
MAX4885 Complete VGA 1:2 or 2:1 Multiplexer ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND.) V+, VCL .....................................................................-0.3V to +6V R_, G_, B_, DDCA_, DDCB_, SEL, M, EN, QP (Note 1) ...........................................-0.3V to V+ + 0.3V H_, V_ .......................................................................-0.3V to +6V Continuous Current Through RGB Switches ....................±70mA Continuous Current Through HV, DDC Switches….....
PAGE 3
Complete VGA 1:2 or 2:1 Multiplexer (V+ = +5.0V ±10%, VCL = +3.3V ±10%, TA = TMIN to TMAX, QP = GND, unless otherwise noted. Typical values are at V+ = +5.0V, VCL = +3.3V and TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 20 Ω DDC MULTIPLEXER On-Resistance RON(DDC) DDC Leakage IL(DDC) VCL - 0.4V < VOUT < VCL, VIN = V+ Q DDCA_, DDCB_ = 0V, CL = 1000pF Input-Low Voltage VIL V+ = +5.5V Input-High Voltage VIH V+ = +4.5V 2.0 VIN = V+ -1 Charge Injection VIN < +0.
PAGE 4
TIMING CHARACTERISTICS (V+ = +5.0V ±10%, VCL = +3.3V ±10%, TA = TMIN to TMAX, QP = GND. Typical values are at V+ = +5.0V, VCL = +3.3V and TA = +25°C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL Charge-Pump Startup Time CONDITIONS MIN TYP tQPON MAX UNITS 150 µs RGB ANALOG SWITCHES Turn-On Time tON VIN = +1.0V, RL = 100Ω, Figure 1 Turn-Off Time tOFF VIN = +1.0V, RL = 100Ω, Figure 1 0.1 µs Propagation Delay tPD CL = 10pF, Figure 2, RL = RS = 50Ω 0.
PAGE 5
Complete VGA 1:2 or 2:1 Multiplexer HV BUFFER OUTPUT VOLTAGE HIGH vs. TEMPERATURE TA = +85°C TA = +25°C TA = -40°C 15 TA = +85°C TA = +25°C TA = -40°C 0 4.0 3.8 3.6 1.0 1.5 2.0 2.5 3.0 -15 0.7 0.6 0.5 0.4 0.3 10 60 85 -40 MAX4885 toc08 1.0 0.9 0.8 2.0 1.5 ON LEAKAGE 1.0 OFF LEAKAGE 10 35 0.5 0.4 0.3 ON LEAKAGE OFF LEAKAGE 0 -40 85 -15 10 35 60 85 -40 -15 10 35 60 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) RGB CHARGE INJECTION vs. COM VOLTAGE SUPPLY CURRENT vs.
PAGE 6
Typical Operating Characteristics (continued) (V+ = +5.0V, VCL = +3.3V and TA = +25°C, unless otherwise noted.) 1.0 0.5 QP = 1 100 75 50 QP = 0 25 0 10 35 60 85 -15 TEMPERATURE (°C) 10 10 35 60 85 -40 TEMPERATURE (°C) RGB PROPAGATION DELAY vs.
PAGE 7
Complete VGA 1:2 or 2:1 Multiplexer V+ MAX4885 R1, G1, B1 R2, G2, B2 VN_ LOGIC INPUT V+ R0, G0, B0 50% 0V VOUT RL t OFF CL SEL VOUT GND LOGIC INPUT SWITCH OUTPUT ( 0.9 x V0UT 0.9 x VOUT 0V t ON CL INCLUDES FIXTURE AND STRAY CAPACITANCE. RL RL + RON VOUT = VN_ t r < 5ns t f < 5ns 50% V+ IN DEPENDS ON SWITCH CONFIGURATION; INPUT POLARITY DETERMINED BY SENSE OF SWITCH. ) Figure 1. Switching Time 1V 50% RS = RL = 50Ω CL = 10pF 50% INPUT 0V VOH tPHL tPLH 0.
PAGE 8
Complete VGA 1:2 or 2:1 Multiplexer MAX4885 Timing Circuits/Timing Diagrams (continued) +5V 10nF V OFF-ISOLATION = 20log ✕ OUT VIN NETWORK ANALYZER 0V OR V+ V+ SEL 50Ω VIN 50Ω ON-LOSS = 20log ✕ R0, G0, B0 MAX4885 R1, G1, B1 50Ω R2, G2, B2 GND VOUT MEAS 50Ω REF VOUT VIN V CROSSTALK = 20log ✕ OUT VIN 50Ω MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS. OFF-ISOLATION IS MEASURED BETWEEN R0 AND R1 OR R2 ON EACH SWITCH. ON-LOSS IS MEASURED BETWEEN R0 AND R1 OR R2 ON EACH SWITCH.
PAGE 9
Complete VGA 1:2 or 2:1 Multiplexer PIN NAME 18 H2 Horizontal Sync I/O FUNCTION 19 V2 Vertical Sync I/O 22 V1 Vertical Sync I/O 23 H1 Horizontal Sync I/O 24 B1 RGB Analog I/O 25 G1 RGB Analog I/O 26 R1 RGB Analog I/O 27 DDCB1 DDC I/O 28 DDCA1 DDC I/O 31 M 32 SEL Select. Logic input for switching RGB, HV, and DDC switches. See Tables 1, 2, and 3. EP EP Exposed Pad. Connect exposed pad to ground. Mode Select. Drive M low for 1:2 multiplexer mode.
PAGE 10
MAX4885 Complete VGA 1:2 or 2:1 Multiplexer standard VGA signals. The charge pump can be disabled to eliminate charge-pump noise; however, RGB switch performance is slightly degraded. Connect QP to ground for normal operation. Horizontal/Vertical Sync Multiplexer 1:2 Multiplexer Mode The MAX4885 provides two modes of operation for the HSYNC and VSYNC signals. In 1:2 mode (M = 0), the HSYNC/VSYNC inputs are buffered to provide level shifting and drive capability to meet the VESA specification.
PAGE 11
Complete VGA 1:2 or 2:1 Multiplexer CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF RD 1500Ω IP 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR MAX4885 RC 1MΩ PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) Ir AMPERES DEVICE UNDER TEST 36.8% 10% 0 0 Figure 5. Human Body ESD Test Model tRL TIME tDL CURRENT WAVEFORM Figure 6. HBM Discharge Current Waveform 2:1 Multiplexer PC Board Layout In 2:1 mode, HSYNC and VSYNC buffers are disabled, allowing bidirectional signaling.
PAGE 12
Complete VGA 1:2 or 2:1 Multiplexer MAX4885 Functional Diagram MAX4885 M H0 * V0 * H1 V1 H2 V2 SEL R1 R0 G1 G0 B1 B0 R2 QP RGB CHARGE PUMP G2 B2 EN DDCA1 DDCA0 DDCB1 DDCB0 VCL VOLTAGE CLAMP DDCA2 DDCB2 12 ______________________________________________________________________________________
PAGE 13
Complete VGA 1:2 or 2:1 Multiplexer QFN THIN.EPS 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.