MAXIM MAX9511

19-3669; Rev 0; 4/05
Complete VGA Interface with
EMI Suppression
The MAX9511 is a complete solution to interface a
video graphics controller to a VGA port and/or docking
station with optimal video performance and minimal
electromagnetic interference (EMI) emission. The
MAX9511 has output drivers with variable EMI suppression for graphics video and sync (RGBHV) signals. The
MAX9511 includes external load-detection circuitry.
The MAX9511 suppresses EMI emissions by limiting
the slew rate (SR) rather than limiting bandwidth with
fixed L-C filters. The SR controls the large-signal bandwidth without affecting the small-signal bandwidth,
resulting in sharper video images, while reducing EMI.
The SR of the MAX9511 provides tighter control than
traditional passive L-C components, and allows the SR
to track the resolution by varying an external resistor
(RRX) rather than being fixed to a sub-optimal value.
The load-detection circuitry of the MAX9511 automatically
detects and transmits a change in load status to the input
stages when an external load (monitor, docking station, or
projector) is connected. The MAX9511 is compatible with
the load-detection circuitry on the digital-to-analog (DAC)
outputs of most video graphics controllers. The output
drivers provide 6dB of gain to compensate for the 75Ω
back-termination resistors, which reduce transmission line
reflections.
The RGBHV channels can be placed into shutdown to
reduce power when no external load is connected.
The MAX9511 operates from 3V and 5V supplies. The
DDC circuitry performs bidirectional level translation
from 3V to 5V logic levels. The MAX9511 is offered in a
24-pin QSOP package and is specified over the commercial 0°C to +70°C temperature range.
Features
♦ RGB Drivers with Adjustable Slew Rate for EMI
Control
♦ H Sync and V Sync Drivers with Level Translation
♦ Bidirectional Level Translators for DDC Support
♦ Simultaneously Drives External Monitor/Projector
and Docking Station without Analog RGB
Switches—No Stub Reflections
♦ Eliminates Up to 34 External Components
♦ Small 24-Pin QSOP Package
Ordering Information
PART
TEMP RANGE
MAX9511CEG
0°C to +70°C
Notebook PCs (Laptops)
Docking Stations
Graphics Cards for Notebooks and Personal
Computers
Personal Computer Motherboards with On-Board
Video Graphics Controllers
Workstations
PKG
CODE
24 QSOP
E24-2
Pin Configuration
TOP VIEW
VCC 1
24 AGND
GREEN_IN 2
Applications
PINPACKAGE
23 GREEN_OUT
AGND 3
22 AGND
RED_IN 4
BLUE_IN 5
21 RED_OUT
MAX9511
RX 6
20 AGND
19 BLUE_OUT
SHDN 7
18 DGND
DDC_DATA_IN 8
17 DDC_DATA_OUT
DDC_CLK_IN 9
16 DDC_CLK_OUT
H_SYNC_IN 10
15 H_SYNC_OUT
V_SYNC_IN 11
14 V_SYNC_OUT
VDD2 12
13 VDD1
QSOP
________________________________________________________________ Maxim Integrated Products
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.
1
MAX9511
General Description
MAX9511
Complete VGA Interface with
EMI Suppression
ABSOLUTE MAXIMUM RATINGS
DDC_DATA_OUT
to DGND .................(DDC_DATA_IN - 0.1V) to (VDD1 + 0.3V)
DDC_CLK_IN
to DGND ................(DDC_CLK_OUT - 0.3V) to (VDD2 + 0.3V)
DDC_CLK_OUT
to DGND....................(DDC_CLK_IN - 0.1V) to (VDD1 + 0.3V)
DDC_DATA_OUT to DDC_DATA_IN ........................-0.1V to +6V
DDC_CLK_OUT to DDC_CLK_IN.............................-0.1V to +6V
Continuous Power Dissipation (TA = +70°C)
24-Pin QSOP (derate 9.5mW/°C above +70°C)..........762mW
Operating Temperature Range...............................0°C to +70°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
VCC to AGND............................................................-0.3V to +6V
VDD1, VDD2 to DGND ...............................................-0.3V to +6V
DGND to AGND.....................................................-0.1V to +0.1V
RED_IN, GREEN_IN, BLUE_IN to AGND.....-0.3V to (VCC + 0.3V)
RED_OUT, GREEN_OUT, BLUE_OUT
to AGND ................................................-0.3V to (VCC + 0.3V)
RX to AGND................................................-0.3V to (VCC + 0.3V)
H_SYNC_IN, V_SYNC_IN, SHDN
to DGND ..............................................-0.3V to (VDD2 + 0.3V)
H_SYNC_OUT, V_SYNC_OUT
to DGND ..............................................-0.3V to (VDD1 + 0.3V)
DDC_DATA_IN
to DGND..............(DDC_DATA_OUT - 0.3V) to (VDD2 + 0.3V)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = 5V, VDD1 = 5V, VDD2 = SHDN = 3V, RL = 150Ω to AGND, DGND = AGND, RRX = 7kΩ to AGND, TA = 0°C to +70°C. Typical
values are at TA = +25°C.)
PARAMETER
Supply Voltage Range
SYMBOL
CONDITIONS
MIN
TYP
MAX
VCC
Inferred from PSRR
4.5
5.5
VDD1
Inferred from logic test
4.5
5.5
VDD2
Inferred from logic test
2.3
3.6
ICC
SHDN = VDD2
RRX = 7kΩ
38
RRX = 36kΩ
SHDN = DGND
Quiescent Supply Current
IDD1
IDD2
SHDN = VDD2
UNITS
V
50
25
35
0.15
0.25
mA
3
6
0.027
0.08
SHDN = VDD2
220
500
SHDN = DGND
26
40
0
0.7
0.9
100
190
290
mV
+1.9
+2
+2.1
V/V
1
2
%
SHDN = DGND
µA
VIDEO
Input Voltage Range
Output Black Level Voltage
VIN
Inferred from voltage gain
VOUT,BLACK RED_IN = GREEN_IN = BLUE_IN = AGND
AV
0 ≤ VIN ≤ 0.9V, RL = 75Ω
Gain Matching
∆AV
0 ≤ VIN ≤ 0.9V, RL = 75Ω
Input Resistance
RIN
Output Short-Circuit Current
(To AGND)
IOUT
Voltage Gain
Load-Detection Voltage
VX_IN
Output Load Detection
RL_OUT
Power-Supply Rejection
PSRR
Large-Signal Bandwidth
2
0 ≤ VIN ≤ 1V, with load
0.02
60
0.4V ≤ VIN ≤ 0.7V, no load
-80
-72
MΩ
-65
40
(Note 1)
200
4.5V ≤ VCC ≤ 5.5V, VIN = 0.5V
40
VOUT = 1.6VP-P, RRX = 7kΩ
Ω
mA
0.315
VIN = 0.4V
V
V
Ω
48
dB
370
MHz
_______________________________________________________________________________________
Complete VGA Interface with
EMI Suppression
(VCC = 5V, VDD1 = 5V, VDD2 = SHDN = 3V, RL = 150Ω to AGND, DGND = AGND, RRX = 7kΩ to AGND, TA = 0°C to +70°C. Typical
values are at TA = +25°C.)
PARAMETER
Slew Rate (Notes 2, 3)
Settling Time
SYMBOL
SR
tS
Undershoot/Overshoot
Linearity Error
LE
SNR
Channel-to-Channel Skew
∆t
PSRR
Crosstalk
Input Termination Switch
Delay
CONDITIONS
TYP
MAX
250
330
450
RRX = 7kΩ, TA = +25°C
900
1100
1300
(Notes 4, 5)
tOS, tUS
Peak Signal-to-Noise Ratio
Power-Supply Rejection
Ratio
MIN
RRX = 36kΩ, TA = +25°C
VIN = 700mVP-P (Notes 6, 7)
UNITS
V/µs
0
ns
±1
%
0.036
%
f = 100kHz to 100MHz, VIN = 700mVP-P
50
dB
R to G to B (Note 3)
500
f = 100kHz
49
dB
All hostile, f = 10MHz
55
dB
70
ns
∆tSWD
1100
ps
LOGIC
Input Low Level
VIL
H_SYNC_IN, V_SYNC_IN and SHDN
Input High Level
VIH
H_SYNC_IN, V_SYNC_IN and SHDN
IOL = 4mA
Output Low Level
VOL
IOH = 4mA
VOH
0.7 x
VDD2
H_SYNC_OUT, VH_SYNC_IN = DGND
0.55
IOH =
50µA
IOH =
50µA
0.4
DDC_DATA_OUT, VDDC_DATA_IN =
DGND
DDC_CLK_OUT, VDDC_CLK_IN = DGND
H_SYNC_OUT, VH_SYNC_IN = VDD2
V_SYNC_OUT, VV_SYNC_IN = VDD2
DDC_DATA_IN, VDDC_DATA_OUT = VDD1
DDC_CLK_IN, VDDC_CLK_OUT = VDD1
DDC_DATA_OUT, VDDC_DATA_IN =
VDD2
DDC_CLK_OUT, VDDC_CLK_IN = VDD2
V
V
V_SYNC_OUT, VV_SYNC_IN = DGND
DDC_DATA_IN, VDDC_DATA_OUT =
IOL = 50µA DGND
DDC_CLK_IN, VDDC_CLK_OUT = DGND
IOL = 3mA
Output High Level
0.3 x
VDD2
V
0.5
VDD1
- 1.5
VDD2
- 0.4
V
VDD1
- 1.5
SYNC Output Resistance
RSO
35
55
85
Ω
SHDN Pulldown Resistance
RSD
250
330
500
kΩ
SYNC Input Resistance
RSI
30
47
65
kΩ
2
3
4
3.0
4.7
6.5
DDC Pullup Resistance
RPO
DDC_DATA_OUT, DDC_CLK_OUT
RPI
DDC_DATA_IN, DDC_CLK_IN
kΩ
_______________________________________________________________________________________
3
MAX9511
ELECTRICAL CHARACTERISTICS (continued)
ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V, VDD1 = 5V, VDD2 = SHDN = 3V, RL = 150Ω to AGND, DGND = AGND, RRX = 7kΩ to AGND, TA = 0°C to +70°C. Typical
values are at TA = +25°C.)
PARAMETER
SYMBOL
Rise/Fall Time
CONDITIONS
tPLH, tPHL
MIN
TYP
CSYNC = 47pF, TA = +25°C
All SYNC outputs
(Notes 2, 3)
tR/tF
Propagation Delay
MAX
UNITS
100
ns
22
ns
7
CSYNC = 470pF, TA = +25°C
50
70
DDC only, CL = 47pF
400
SYNC, CSYNC = 47pF, TA = +25°C (Notes 3, 8)
12
Enable Time
VIN = 0.7VP-P, SHDN from DGND to VDD2, outputs
settle to ±1% of final value
1200
ns
Disable Time
VIN = 0.7VP-P, SHDN from VDD2 to DGND, outputs
settle to ±1% of final value
400
ns
This is the voltage at which the input termination switches; VIN > VX_IN = switch open, VIN < VX_IN = switch closed.
Measured between the 10% to 90% points on rising or falling edge.
Not production tested. Guaranteed by design.
Measured from the END of overshoot/undershoot to ±5% of final value.
VIN = 700mV with a rise time >1ns.
Linearity error is the maximum difference between the actual and measured output of a video ramp. Done in accordance
with VESA Test Procedure, Version 1, 6/11/2001.
Note 7: Linearity error measured as percentage of full scale.
Note 8: Propagation delay is the time difference between the VDD2 / 2 input crossing and the 1.4V output crossing.
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Typical Operating Characteristics
(VCC = 5V, VDD1 = 5V, VDD2 = 3V, RL = 150Ω to AGND, RRX = 7kΩ to AGND, TA = +25°C, unless otherwise noted.)
1
0.4
3
0.3
2
1
0
-1
0.1
-1
-2
-3
GAIN (dB)
0.2
GAIN (dB)
0
0
-0.1
-2
-0.2
-4
-5
-0.3
-5
-6
-0.4
-6
-7
-0.5
-7
1
10
FREQUENCY (MHz)
100
1000
0.1
1
10
FREQUENCY (MHz)
100
1000
RRX = 5kΩ
-3
-4
0.1
4
LARGE-SIGNAL BANDWIDTH
vs. FREQUENCY vs. RRX
MAX9511 toc02
VOUT = 1.6VP-P
TA = TMIN to TMAX
2
0.5
MAX9511 toc01
3
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY
MAX9511 toc03
LARGE-SIGNAL BANDWIDTH
vs. FREQUENCY
GAIN (dB)
MAX9511
Complete VGA Interface with
EMI Suppression
RRX = 20kΩ
RRX = 35kΩ
RRX = 50kΩ
0.1
1
10
FREQUENCY (MHz)
_______________________________________________________________________________________
100
1000
Complete VGA Interface with
EMI Suppression
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY vs. RRX
SMALL-SIGNAL BANDWIDTH
vs. FREQUENCY vs. RRX
1
0.4
0.3
0.2
-1
0.1
GAIN (dB)
0
-2
RRX = 5kΩ
-3
RRX = 20kΩ
-4
-5
RRX = 35kΩ
-6
RRX = 50kΩ
MAX9511 toc05
2
GAIN (dB)
0.5
MAX9511 toc04
3
RRX = 5kΩ
0
RRX = 20kΩ
-0.1
RRX = 35kΩ
-0.2
-0.3
RRX = 50kΩ
-0.4
-0.5
-7
0.1
1
10
100
1000
0.1
10,000
1
ALL-HOSTILE CROSSTALK
vs. FREQUENCY
-30
-40
TA = +85°C
TA = 0°C, +25°C
-70
1000
MAX9511 toc07
-20
OFF-ISOLATION (dB)
-20
-80
-40
-60
-80
-100
-90
-120
-100
1
10
100
0.1
1000
1
10
100
1000
FREQUENCY (MHz)
FREQUENCY (MHz)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
TRANSIENT RESPONSE
MAX9511 toc08
0
MAX9511 toc09
0.1
-10
VIN
500mV/div
0V
-20
PSRR (dB)
CROSSTALK (dB)
0
MAX9511 toc06
-10
-60
100
OFF-ISOLATION vs. FREQUENCY
0
-50
10
FREQUENCY (MHz)
FREQUENCY (MHz)
TA = +70°C
-30
-40
VOUT
1V/div
-50
OV
-60
TA = 0°C
TA = +25°C
-70
2ns/div
0.01
0.1
1
10
100
1000
FREQUENCY (MHz)
_______________________________________________________________________________________
5
MAX9511
Typical Operating Characteristics (continued)
(VCC = 5V, VDD1 = 5V, VDD2 = 3V, RL = 150Ω to AGND, RRX = 7kΩ to AGND, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = 5V, VDD1 = 5V, VDD2 = 3V, RL = 150Ω to AGND, RRX = 7kΩ to AGND, TA = +25°C, unless otherwise noted.)
DDC_IN TO DDC_OUT
PULSE RESPONSE
SYNC PULSE RESPONSE
MAX9511 toc10
MAX9511 toc11
RL = 2.2kΩ
RL = 100kΩ
CL = 47pF
INPUT
1V/div
INPUT
1V/div
0V
OUTPUT
1V/div
CL = 47pF
CL = 150pF
CL = 220pF
CL = 330pF
CL = 510pF
0V
OUTPUT
2V/div
tR = 250ns
tF = 30ns
0V
0V
50µs/div
500ns/div
POWER-SUPPLY CURRENT
vs. TEMPERATURE (ICC)
DDC_OUT TO DDC_IN
PULSE RESPONSE
MAX9511 toc12
48
INPUT
2V/div
0V
OUTPUT
1V/div
MAX9511 toc13
50
RL = 100kΩ
CL = 47pF
tR = 280ns
tF = 4ns
0V
POWER-SUPPLY CURRENT (mA)
MAX9511
Complete VGA Interface with
EMI Suppression
46
44
42
40
38
36
34
32
30
500ns/div
0
25
50
TEMPERATURE (°C)
6
_______________________________________________________________________________________
75
Complete VGA Interface with
EMI Suppression
2.5
2.0
1.5
MEAN
200
150
MEAN - 3 x SIGMA
100
-66
-68
-70
-72
-78
0
0
25
-64
-76
50
IDD2
0
0.4V ≤ VIN ≤ 0.7V
NO LOAD
-62
-74
1.0
0.5
-60
RESISTANCE (Ω)
3.0
MEAN + 3 x SIGMA
250
OFFSET VOLTAGE (mV)
POWER-SUPPLY CURRENT (mA)
IDD1
300
MAX9511 toc15
SHDN = VDD2
MAX9511 toc14
4.0
3.5
INPUT RESISTANCE
vs. TEMPERATURE
OUTPUT OFFSET
vs. TEMPERATURE (VOUT,BLACK)
MAX9511 toc16
POWER-SUPPLY CURRENT
vs. TEMPERATURE (IDD1, IDD2)
50
75
-80
0
TEMPERATURE (°C)
25
50
75
0
25
TEMPERATURE (°C)
50
75
TEMPERATURE (°C)
Pin Description
PIN
NAME
1
VCC
2
GREEN_IN
FUNCTION
Analog Power Supply
Green Video Input
3, 20, 22, 24
AGND
Analog Ground
4
RED_IN
Red Video Input
5
BLUE_IN
6
RX
7
SHDN
8
DDC_DATA_IN
9
DDC_CLK_IN
10
H_SYNC_IN
11
V_SYNC_IN
12
VDD2
SYNC/DDC 3V Supply
13
VDD1
SYNC/DDC 5V Supply. Supplies 5V to SYNC and DDC output circuitry.
Blue Video Input
Slew-Rate Control. Connect an external resistor from RX to AGND.
Active-Low Shutdown. For normal operation connect to VDD2. SHDN is internally pulled to DGND.
DDC Data Input. Defaults to VDD2 through an internal pullup resistor.
DDC Clock Input. Defaults to VDD2 through an internal pullup resistor.
Horizontal SYNC Input. Defaults to AGND through an internal pulldown resistor.
Vertical SYNC Input. Defaults to AGND through an internal pulldown resistor.
14
V_SYNC_OUT
Vertical Sync Output
15
H_SYNC_OUT
Horizontal Sync Output
16
DDC_CLK_OUT
17
DDC Clock Output. Defaults to VDD1 through an internal pullup resistor.
DDC_DATA_OUT DDC Data Output. Defaults to VDD1 through an internal pullup resistor.
18
DGND
19
BLUE_OUT
Digital Ground
Blue Video Output
21
RED_OUT
Red Video Output
23
GREEN_OUT
Green Video Output
_______________________________________________________________________________________
7
MAX9511
Typical Operating Characteristics (continued)
(VCC = 5V, VDD1 = 5V, VDD2 = 3V, RL = 150Ω to AGND, RRX = 7kΩ to AGND, TA = +25°C, unless otherwise noted.)
Complete VGA Interface with
EMI Suppression
MAX9511
Block Diagram
VCC
MAX9511
RISENSE
VY
GREEN_IN
GREEN_OUT
-75Ω
VX
RISENSE
VY
RED_IN
RED_OUT
-75Ω
VX
RISENSE
VY
Detailed Description
The MAX9511 solves several difficult problems in interfacing a video graphics controller to a VGA port and/or
the docking station connector. First, there is a trade-off
between video quality and EMI. The usual method for
reducing EMI is to insert a fixed-frequency LC π-filter
between the video DAC output and the connector. Given
the large component variation of the capacitors and
inductors, the frequency response is sharply reduced to
meet EMI requirements. As a result, video quality suffers
making sharp transitions in the video soft. The MAX9511
video drivers have a variable slew rate, which limits electromagnetic emissions and can be adjusted by an external resistor. As a result, the slew rate of the MAX9511 can
be varied to reduce electromagnetic emissions at a given
resolution, maximizing video quality. Since the slew rate
is variable and set by a resistor instead of fixed by
capacitors and inductors, video performance and electromagnetic emissions are consistent during production.
The MAX9511 also has horizontal and vertical sync output drivers, bidirectional level translators for DDC support, and external load-detection circuits that correctly
transfer information about the external load to the video
graphics controller.
Load Detection
BLUE_IN
BLUE_OUT
-75Ω
RX
VX
VDD1
VDD2
SHDN
RPI
RPI
RPO
RB
DDC_DATA_IN
DDC_DATA_OUT
RB
RPO
DDC_CLK_IN
DDC_CLK_OUT
RSO
H_SYNC_IN
H_SYNC_OUT
RSI
RSO
V_SYNC_IN
RSI
AGND
8
DGND
V_SYNC_OUT
Most notebook computers implement a power-saving
load-detection circuit that disables the external monitor
output when no monitor is plugged into the rear panel
VGA connector as shown in Figure 1. Upon startup or on
command, the video controller generates a sequence of
detection pulses out of the current DAC shown, that
results in an output voltage of above 315mV when an
external monitor (RL) is connected, and above 630mV
when disconnected. If the monitor is disconnected at the
time of the pulse, the comparator inside the notebook
trips and disables the video. When the monitor is
plugged in, the resulting pulse will not trip the comparator
and the video is enabled.
If the lowpass filter is simply replaced with an amplifier,
the monitor termination RL is isolated from the video
controller and the conventional load-detection scheme
does not work.
For this reason, the MAX9511 includes the load-detection
circuit. When RL is connected (i.e., the monitor is plugged
in) to the output of the MAX9511, the internal load-detection circuit disconnects the synthesized -75Ω resistor
from the input. The resulting 37.5Ω resistance at the DAC
output indicates to the DAC’s internal load-detection circuit that the monitor is plugged in. Removing RL (i.e., disconnecting the monitor) causes the MAX9511’s
load-detection circuit to connect the synthesized -75Ω
_______________________________________________________________________________________
Complete VGA Interface with
EMI Suppression
MAX9511
MONITOR
VIDEO CONTROLLER
LOWPASS FILTER
FOR EMI SUPPRESSION
IOUT
RT
75Ω
REF
RL
75Ω
CURRENT DAC
Figure 1. Conventional Load-Detection Scheme
VIDEO CONTROLLER
MONITOR
RISENSE
MAX9511
VY
VIS
IOUT
G=2
OUT
REF
RT
37.5Ω
RT
75Ω
RL
75Ω
-75Ω
CURRENT DAC
VX
Figure 2. Load-Detection Scheme with MAX9511
resistor to the input. This results in an equivalent impedance of 75Ω at the DAC output, which indicates to the
video controller’s internal load-detection circuit that the
load is disconnected and the video controller shuts down
the video output. Figure 2 and Table 1 demonstrate how
the MAX9511 load-detection circuit operates in conjunction with the video controller load detection.
Output Video Signal Level Shift
The video signal at the MAX9511 output is shifted
upwards by approximately 240mV from the input to
keep the output stage of the video driver in a linear
region of operation. At the connector, the video signal
is attenuated by 6dB, canceling the 6dB gain of the
video driver. The 240mV level shift is also attenuated by
6dB, and hence the actual video signal seen by the
load is only 120mV higher than the video signal at the
input of the MAX9511. Monitors and other display
devices AC-couple the input signal so the 120mV level
shift should not affect the displayed video image.
Table 1. Function of Load-Detection
Scheme
AMPLIFIER OUTPUT
Connected to External Load
Not Connected to External Load
MAX9511 RESISTANCE
AT DAC
INTERNAL
OUTPUT
SWITCH
Open
37.5Ω
Closed
75Ω
_______________________________________________________________________________________
9
Vertical and Horizontal SYNC
Display Data Channel (DDC)
The MAX9511 bidirectional display data channel (DDC)
level translator allows for a lower voltage video controller
logic to operate with a higher voltage external monitor
logic. Power supplied at VDD2 defines the DDC input
voltage thresholds while power supplied at VDD1 defines
the DDC output thresholds. Two Schottky-clamped npn
transistors shift the lower level DDC inputs to higher
logic-level outputs.
DDC_CLK_OUT and DDC_DATA_OUT are pulled to
VDD1 by internal pullup resistors to prevent ambiguous
conditions when left floating. At shutdown, DDC inputs
can still respond to external commands.
Slew-Rate Limiting
The MAX9511 outputs are slew-rate limited to reduce
EMI. Slew-rate limiting affects the large-signal bandwidth
(LSBW) more than the small-signal bandwidth (SSBW),
and can be scaled according to the following formula:
LSBW(−3dB) =
SR
2 × π × VOUT
where VOUT is the output signal’s peak-to-peak voltage
and LSBW(-3dB) is the -3dB bandwidth.
The slew rate of the MAX9511 is controlled by a resistor
between RX and AGND. The resistor (RRX) can be varied to optimize the EMI suppression to the display resolution while preserving the display quality. The RRX
range is approximately 7kΩ for maximum slew rate and
38kΩ for minimum slew rate (see Figure 3). Slew-rate
limiting can be approximated by:
SLEW RATE vs. RRX
1600
MAX9511 fig03
The MAX9511 has separate, noninverting, vertical and
horizontal sync buffers. Both sync inputs can level-shift
an input as low as 2.3V to a 5V output. Both sync drivers
have hysteresis at their input to prevent “chatter” in their
outputs. The sync output drivers have a 55Ω (typ) output impedance (RSO) to match the cable impedance
used for vertical and horizontal sync in most applications. Both sync inputs are pulled to DGND through a
47kΩ resistor if the controller’s SYNC source goes high
impedance, or if the inputs are left floating, avoiding
ambiguous output conditions.
EMI can result from rapid transitions of the sync or the
video signals. To reduce the rise and fall times of the
sync signal, additional capacitance may be added to
the sync outputs. Adding additional capacitance may
require “recentering” the display.
1400
1200
SLEW RATE (V/µs)
MAX9511
Complete VGA Interface with
EMI Suppression
1000
800
600
400
200
0
0
10
20
30
50
Figure 3. Slew Rate vs. RRX
Shutdown
The MAX9511 features a low-power shutdown mode for
battery-powered/portable applications. Shutdown
reduces the quiescent current of the video and sync drivers. Connecting SHDN to ground (DGND) disables the
outputs and places the MAX9511 into a low-power shutdown mode. SHDN has a 330kΩ (typ) internal pulldown
resistor to DGND. Connect SHDN to VDD2 for normal
operation.
Applications Information
Customizing Slew Rates for
Different Resolutions
When the MAX9511 connects to devices of different
resolutions, different slew rates should be used. The
slew rate of the MAX9511 is adjustable by varying RRX
between 7kΩ and 38kΩ. By selecting a valid RRX value
for a resolution, the MAX9511 minimizes the EMI and
optimizes the video output quality. Shown are two configurations to adjust slew rates using different RRX values for different video resolutions.
Figure 4 shows how to customize slew rates for three resolutions. This circuit provides three predetermined slew
rates by paralleling resistors to create three RRX values.
The combination is controlled by a digital command from
the video controller through a switch. This requires that
the sample clock rates used by different resolutions are
close. The sync bandwidth-limiting capacitors (CSYNC)
are set for the highest resolution.
 7000 
SR = 1030 
 (V / µs)
 RRX 
10
40
RRX (kΩ)
______________________________________________________________________________________
Complete VGA Interface with
EMI Suppression
4.7µF
CSYNC
0.22µF
0.1µF
0.1µF
1nF
REMOTE MONITOR
7
8
9
10
11
VDD2
DDC_DATA_OUT
DDC_CLK_IN
DDC_CLK_OUT
H_SYNC_IN
H_SYNC_OUT
V_SYNC_IN
DOCKING STATION
VCC
DDC_DATA_IN
V_SYNC_OUT
MAX9511
4
1
12
13
SHDN VDD1
VIDEO CONTROLLER
CSYNC
2.3V TO 3.6V
5V
POWERMANAGEMENT
CIRCUIT
MAX9511
SYNC BANDWIDTH
LIMITING CAPACITORS
CSYNC = 47pF TO 470pF
5V
GREEN_OUT
17
16
15
14
23
75Ω
75Ω
RED_IN
RED_OUT
21
75Ω
75Ω
37.5Ω
BLUE_OUT
19
75Ω
75Ω
2
GREEN_IN
37.5Ω
5
BLUE_IN
RX
6
37.5Ω
R1 = 47kΩ
AGND
3, 20, 22, 24
DGND
COM2
NO1
COM1
NO2
18
R2 = 47kΩ
IN1
R3 = 18kΩ
IN2
MAX4731
Figure 4. Three Resolution Slew-Rate Control
Figure 4 showcases the setup for three commonly used
resolutions: 1600 x 1200, 1280 x 1024, and 1024 x 768.
Since the resolution change is relatively slow, the
switch does not have to be fast. The impedance of the
switch does not need to be low compared to RRX .
When using a high-impedance switch, the resistance
from the switch should be included to calculate RRX.
The MAX4731 50Ω SPST analog switch shown in the
figure is used with three external resistors to get RRX
values of 47kΩ, 23.5kΩ, and 10kΩ for 1600 x 1200,
1280 x 1024, and 1024 x 768 resolutions, respectively.
______________________________________________________________________________________
11
MAX9511
Complete VGA Interface with
EMI Suppression
SYNC BANDWIDTH
LIMITING CAPACITORS
CSYNC = 47pF TO 470pF
5V
4.7µF
CSYNC
0.22µF
0.1µF
POWERMANAGEMENT
CIRCUIT
0.1µF
1nF
REMOTE MONITOR
7
8
9
10
11
VDD2
DDC_DATA_OUT
DDC_CLK_IN
DDC_CLK_OUT
H_SYNC_IN
H_SYNC_OUT
V_SYNC_IN
DOCKING STATION
VCC
DDC_DATA_IN
V_SYNC_OUT
MAX9511
4
1
12
13
SHDN VDD1
VIDEO CONTROLLER
CSYNC
2.3V TO 3.6V
5V
GREEN_OUT
17
16
15
14
75Ω
23
75Ω
RED_IN
RED_OUT
75Ω
21
75Ω
37.5Ω
BLUE_OUT
2
75Ω
19
75Ω
GREEN_IN
37.5Ω
5
BLUE_IN
RX
6
7kΩ
H
37.5Ω
AGND
3, 20, 22, 24
W
DGND
R1 = 80kΩ
18
SDA
SCL
MAX5432
L
Figure 5. Slew-Rate Control with a Digital Potentiometer
The circuit in Figure 5 uses a MAX5432 digital potentiometer to provide more flexibility in customizing slew
rates. An 80kΩ external trim resistor is placed in parallel
12
with the 50kΩ MAX5432 to limit the maximum value of
RRX to 38kΩ. This setup provides 33 levels of RRX values through the I2C control ports at the MAX5432.
______________________________________________________________________________________
Complete VGA Interface with
EMI Suppression
SYNC Bandwidth-Limiting Capacitors
The output impedance, RSO, of the MAX9511 and an
additional capacitance (CSYNC) can form a lowpass filter that reduces the jitter of the sync output signal. With
RSO (55Ω typ) sync output impedance, the -3dB point
of the lowpass filter is given by:
f-3dB =
1
2πRSOCSYNC
Power-Supply Bypassing and
Ground Management
The MAX9511’s high-frequency performance requires
proper layout and bypassing. For best performance,
place components as close to the device as possible.
Digital or AC transient signals on AGND can create
noise at the outputs. Return AGND to the lowest impedance ground available. Bypass the analog supply
(VCC) with a 4.7µF capacitor paralleled with a 0.22µF
and 0.001µF capacitor to AGND, placed as close to the
device as possible. Bypass the digital supplies (VDD1,
VDD2) with a 0.1µF capacitor to DGND, placed as close
to the device as possible. Careful PC board ground layout minimizes crosstalk between the outputs.
Choose CSYNC so f-3dB is well above the highest frequency of interest.
Chip Information
TRANSISTOR COUNT: 353
PROCESS: BIPOLAR
______________________________________________________________________________________
13
MAX9511
Power Supplies
The MAX9511 operates with a 4.5V to 5.5V power supply for video (RGBHV), while DDC and SYNC operate
from 2.3V to 3.6V and 4.5V to 5.5V supplies.
Complete VGA Interface with
EMI Suppression
MAX9511
Typical Operating Circuit
SYNC BANDWIDTH
LIMITING CAPACITORS
CSYNC = 50pF TO 500pF
5V
4.7µF
CSYNC
0.22µF
0.1µF
POWERMANAGEMENT
CIRCUIT
0.1µF
1nF
REMOTE MONITOR
7
12
13
SHDN VDD1
8
9
10
11
VIDEO CONTROLLER
CSYNC
2.3V TO 3.6V
5V
VDD2
DDC_DATA_OUT
DDC_CLK_IN
DDC_CLK_OUT
H_SYNC_IN
H_SYNC_OUT
V_SYNC_IN
DOCKING STATION
VCC
DDC_DATA_IN
V_SYNC_OUT
MAX9511
4
1
GREEN_OUT
17
16
15
14
75Ω
23
75Ω
RED_IN
RED_OUT
75Ω
21
75Ω
37.5Ω
BLUE_OUT
75Ω
19
75Ω
2
GREEN_IN
37.5Ω
5
BLUE_IN
RX
6
37.5Ω
AGND
3, 20, 22, 24
14
DGND
RRX
18
______________________________________________________________________________________
Complete VGA Interface with
EMI Suppression
QSOP.EPS
PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH
21-0055
E
1
1
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
© 2005 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
MAX9511
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)