General Description
The MAX11508/MAX11509 integrated 3-channel video
filters for high-definition (HD), progressive-scan (PS),
standard-definition (SD), and bypass (BP) video
include an output buffer with +6dB gain and are ideal
for digital video disc (DVD) players, set-top box (STB)
receivers, high-definition television (HDTV), digital
video recorders (DVRs), and similar devices.
The MAX11508/MAX11509 video inputs feature a transparent clamp compatible with AC- and DC-coupled
input signals and allow DAC outputs to be directly coupled, eliminating the need for bulky coupling capacitors. The filter bandwidths are selectable to HD, PS,
and SD. A BP mode is provided for 1080p and highbandwidth RGB signals. Selectable input bias circuitry
on 2 filter channels offers simple connection to bipolar
video signals such as C, Pb, and Pr.
The MAX11508 filters provide -3dB bandwidths of 9MHz
(SD), 16MHz (PS), 33MHz (HD), and 60MHz (BP). The
MAX11509 filters provide -3dB bandwidths of 10MHz
(SD), 17MHz (PS), 34MHz (HD), and 60MHz (BP).
Each channel includes an output buffer with +6dB gain
that provides a full 2V
P-P
video signal into a 150Ω video
load. The buffers drive either AC- or DC-coupled loads
and assure a blanking level of below 1V after the backmatch resistor. The shutdown mode provided reduces
device current to 1µA (typ).
The MAX11508 offers a flat passband and the
MAX11509 features +0.8dB peaking to compensate for
DAC rolloff. The MAX11508/MAX11509 operate from a
5V power supply and operate over the upper commercial (0°C to +85°C) temperature range. The parts are
offered in the 14-pin TSSOP package.
Applications
Cable and Satellite STB Receivers
HDTV
DVD Players
Personal Video Recorders
DVRs
Video-On-Demand
HD Recorders
Features
♦ Three Selectable 6th-Order 9MHz/16MHz/33MHz
(SD/PS/HD) Filters
♦ Bypass Mode for High Bandwidth Signals
♦ Transparent Input Clamp
♦ Output Buffers Drive a Standard 150Ω Video Load
♦ ±12kV HBM ESD Protection on Outputs
♦ AC- or DC-Coupled Inputs
♦ AC- or DC-Coupled Outputs
♦ +0.8dB Peaking Passband Response (MAX11509)
in SD, PS, and HD Modes
♦ Single +5V Power Supply
♦ Lead-Free, 14-Pin TSSOP Package
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
________________________________________________________________
Maxim Integrated Products
1
Pin Configuration
Ordering Information
19-4346; Rev 0; 10/08
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.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
0°C to +85°C 14 TSSOP
0°C to +85°C 14 TSSOP
Typical Operating Circuit appears at end of data sheet.
+
Denotes a lead-free/RoHS-compliant package.
MAX11508UUD+
MAX11509UUD+
TOP VIEW
FSEL0
Y/G_IN
Pr/R_IN
BIAS
+
1
V
CC
2
3
MAX11508
MAX11509
4
5
6
7
TSSOP
14
13
12
11
10
9
8
N.C.
FSEL1
Y/G_OUT
Pb/B_OUTPb/B_IN
Pr/R_OUT
SHDN
GNDN.C.
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +5V, R
LOAD
= 150Ω to GND, CIN= 0.1µF, TA= 0°C to +85°C, all frequency responses are relative to 100kHz, unless other-
wise noted.) (Note 1)
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.
VCCto GND..............................................................-0.3V to +6V
All Other Pins to GND...................................-0.3V to the lower of
(V
CC
+ 0.3V) and +6V
Continuous Power Dissipation (T
A
= +70°C)
14-Pin TSSOP (derate 10mW/°C above +70°C) .......796.8mW
Maximum Current into Any Pin Except V
CC
and GND .....±50mA
Operating Temperature Range…. ..........................0°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Junction Temperature......................................................+150°C
DC CHARACTERISTICS
Supply Current I
Supply Voltage Range V
Input Voltage Range V
Power-Down Current I
Digital Input High Voltage V
Digital Input Low Voltage V
STANDARD-DEFINITION VIDEO
-1dB Bandwidth f
-3dB Bandwidth f
Stopband Attenuation A
Low-Frequency Gain A
Differential Gain dG All channels 0.7 %
Differential Phase dφ All channels 0.7 Degrees
Total Harmonic Distortion THD V
Signal-to-Noise Ratio SNR
Group Delay t
Power-Supply Rejection Ratio PSRR DC, all channels 50 dB
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CC
PD
1dB
3dB
No load 24 35 mA
DD
Referenced to GND if DC-coupled 1.4 V
IN
BIAS = high 1
BIAS = low 15
IH
IL
MAX11508, TA = +25°C 4.5 7.9
MAX11509, TA = +25°C 5 8.6
MAX11508 9.0
MAX11509 10
f = 27MHz 35 48 dB
SB
No load 5.6 6.0 6.6 dB
V
= 1.4V
OUT
2V
P-P
f = 100kHz to 4.2MHz
f = 4.5MHz 59 ns
G
P-P
signal to RMS noise,
4.75 5.00 5.25 V
2.0 V
0.8 V
, f = 1MHz, all channels -60 dB
71 dB
µA
MHz
MHz
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
_______________________________________________________________________________________ 3
Note 1: All devices are 100% production tested at TA= +25°C.
Note 2: Output AC-coupled with 220µF into 150Ω to GND.
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +5V, R
LOAD
= 150Ω to GND, CIN= 0.1µF, TA= 0°C to +85°C, all frequency responses are relative to 100kHz, unless other-
wise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
PROGRESSIVE-SCAN VIDEO
-1dB Bandwidth f
-3dB Bandwidth f
Stopband Attenuation A
Low-Frequency Gain A
Total Harmonic Distortion THD V
Signal-to-Noise Ratio SNR
Group Delay t
HIGH-DEFINITION VIDEO
-1dB Bandwidth f
-3dB Bandwidth f
Stopband Attenuation A
Low-Frequency Gain A
Total Harmonic Distortion THD
Signal-to-Noise Ratio SNR
Group Delay t
BYPASS VIDEO (Note 2)
-3dB Bandwidth f
Low-Frequency Gain A
Total Harmonic Distortion THD V
Signal-to-Noise Ratio SNR
1dB
3dB
1dB
3dB
3dB
MAX11508, TA = +25°C 9 13.5
MAX11509, TA = +25°C 10 14
MAX11508 16
MAX11509 17
f = 54MHz 44 dB
SB
V
= 1.4V
OUT
2V
signal to RMS noise,
P-P
f = 100kHz to 15MHz
f = 10MHz 47 ns
G
MAX11508, TA = +25°C 21 30
MAX11509, TA = +25°C 22 31
MAX11508 33
MAX11509 34
f = 37.125MHz 6.5
f = 44.25MHz 14.5
SB
f = 74.25MHz 45
V
V
= 1.4V
OUT
= 1.4V
V
OUT
= 1.4V
V
OUT
2V
signal to RMS noise,
P-P
f = 100kHz to 30MHz
f = 20MHz 25 ns
G
V
= 1.4V
OUT
signal to RMS noise,
2V
P-P
f = 100kHz to 30MHz
, f = 7MHz -55 dB
P-P
, f = 10MHz -55
P-P
, f = 15MHz -50
P-P
, f = 22MHz -40
P-P
, f = 22MHz -40 dB
P-P
MHz
MHz
5.6 6.0 6.6 dB
66 dB
MHz
MHz
dB
5.4 6.0 6.6 dB
dB
65 dB
60 MHz
5.4 6.0 6.6 dB
65 dB
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCC= 5V, RL= 150Ω to GND, output DC-coupled, TA= +25°C, unless otherwise noted.)
MAX11508
SD FREQUENCY RESPONSE
10
0
-10
-20
-30
RESPONSE (dB)
-40
-50
-60
0.1 100
FREQUENCY (MHz)
101
MAX11508 toc01
7
5
3
1
RESPONSE (dB)
-1
-3
0.1 10
MAX11509
7
5
3
1
RESPONSE (dB)
-1
SD PASSBAND RESPONSE
MAX11508 toc04
10
0
-10
-20
-30
RESPONSE (dB)
-40
-50
MAX11508
SD PASSBAND RESPONSE
1
FREQUENCY (MHz)
MAX11508
PS FREQUENCY RESPONSE
MAX11508 toc02
MAX11508 toc05
MAX11509
SD FREQUENCY RESPONSE
10
0
-10
-20
-30
RESPONSE (dB)
-40
-50
-60
0.1 100
FREQUENCY (MHz)
101
MAX11508
PS PASSBAND RESPONSE
7
5
3
1
RESPONSE (dB)
-1
MAX11508 toc03
MAX11508 toc06
MAX11508 toc08
-3
0.1 10010
1
FREQUENCY (MHz)
MAX11508
HD FREQUENCY RESPONSE
10
0
-10
-20
-30
RESPONSE (dB)
-40
-50
-60
0.1 100
FREQUENCY (MHz)
-3
0.1 10
1
FREQUENCY (MHz)
MAX11509
PS FREQUENCY RESPONSE
10
0
-10
-20
-30
RESPONSE (dB)
-40
-50
-60
0.1 100
FREQUENCY (MHz)
101
MAX11508 toc07
-60
0.1 100
FREQUENCY (MHz)
101
MAX11509
PS PASSBAND RESPONSE
7
5
3
1
RESPONSE (dB)
-1
-3
0.1 100
110
FREQUENCY (MHz)
MAX11508 toc09
101
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(VCC= 5V, RL= 150Ω to GND, output DC-coupled, TA= +25°C, unless otherwise noted.)
HD PASSBAND RESPONSE
7
5
3
1
RESPONSE (dB)
-1
-3
0.1 10010
1
FREQUENCY (MHz)
BP FREQUENCY RESPONSE
10
0
-10
-20
MAX11508
MAX11508
MAX11508 toc10
MAX11508 toc13
10
0
-10
-20
-30
RESPONSE (dB)
-40
-50
-60
0.1 100
7
5
3
MAX11509
HD FREQUENCY RESPONSE
101
FREQUENCY (MHz)
MAX11508
BP PASSBAND RESPONSE
MAX11508 toc11
MAX11508 toc14
HD PASSBAND RESPONSE
7
5
3
1
RESPONSE (dB)
-1
-3
0.1 10010
1
FREQUENCY (MHz)
BP FREQUENCY RESPONSE
10
0
-10
-20
MAX11509
MAX11508 toc12
MAX11509
MAX11508 toc15
-30
RESPONSE (dB)
-40
-50
-60
0.1 100
FREQUENCY (MHz)
101
MAX11509
BP PASSBAND RESPONSE
7
5
3
1
RESPONSE (dB)
-1
-3
0.1 10010
1
FREQUENCY (MHz)
MAX11508 toc16
1
RESPONSE (dB)
-1
-3
0.1 10010
1
FREQUENCY (MHz)
MAX11508
SD GROUP DELAY vs. FREQUENCY
120
100
80
60
40
DELAY (ns)
20
0
-20
0.1 100
FREQUENCY (MHz)
101
MAX11508 toc17
-30
RESPONSE (dB)
-40
-50
-60
0.1 100
FREQUENCY (MHz)
101
MAX11509
SD GROUP DELAY vs. FREQUENCY
120
100
80
60
40
DELAY (ns)
20
0
-20
0.1 100
FREQUENCY (MHz)
101
MAX11508 toc18
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VCC= 5V, RL= 150Ω to GND, output DC-coupled, TA= +25°C, unless otherwise noted.)
PS GROUP DELAY vs. FREQUENCY
80
60
40
DELAY (ns)
20
0
-20
0.1 100
FREQUENCY (MHz)
101
MAX11508 toc19
PS GROUP DELAY vs. FREQUENCY
80
60
40
DELAY (ns)
20
0
-20
0.1 100
MAX11509
MAX11508
HD GROUP DELAY vs. FREQUENCY
40
20
0
DELAY (ns)
MAX11508 toc22
BP GROUP DELAY vs. FREQUENCY
40
20
0
DELAY (ns)
MAX11509
FREQUENCY (MHz)
MAX11508
HD GROUP DELAY vs. FREQUENCY
MAX11508
40
MAX11508 toc20
20
0
DELAY (ns)
-20
-40
101
0.1 100
FREQUENCY (MHz)
101
MAX11508 toc21
MAX11509
BP GROUP DELAY vs. FREQUENCY
40
MAX11508 toc23
20
0
DELAY (ns)
MAX11508 toc24
-20
-40
0.1 100
FREQUENCY (MHz)
101
-20
-40
0.1 100
MAX11508
SD DIFFERENTIAL GAIN, NTSC
1.0
0.8
0.6
0.4
0.2
0
-0.2
-0.4
DIFFERENTIAL GAIN (%)
-0.6
-0.8
-1.0
17
56432
STEP
MAX11508 toc25
DIFFERENTIAL PHASE (deg)
SD DIFFERENTIAL PHASE, NTSC
1.0
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
17
101
FREQUENCY (MHz)
MAX11508
56432
STEP
-20
-40
1.0
0.8
MAX11508 toc26
0.6
0.4
0.2
0
-0.2
-0.4
DIFFERENTIAL GAIN (%)
-0.6
-0.8
-1.0
0.1 100
FREQUENCY (MHz)
MAX11509
SD DIFFERENTIAL GAIN, NTSC
17
101
MAX11508 toc27
56432
STEP
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
_______________________________________________________________________________________ 7
Pin Description
Typical Operating Characteristics (continued)
(VCC= 5V, RL= 150Ω to GND, output DC-coupled, TA= +25°C, unless otherwise noted.)
MAX11509
SD DIFFERENTIAL PHASE, NTSC
MAX11508 toc28
STEP
DIFFERENTIAL PHASE (deg)
56432
-0.2
-0.4
-0.6
-0.8
0.2
0.6
0
0.4
0.8
1.0
-1.0
17
MAX11508
SD 2T RESPONSE
MAX11508 toc29
200ns/div
CH1
OUT
CH1: INPUT, 200mV/div
CH2: OUTPUT AFTER BACKMATCH RESISTOR, 200mV/div
IN
CH2
MAX11509
SD 2T RESPONSE
MAX11508 toc30
200ns/div
CH1
OUT
IN
CH2
CH1: INPUT, 200mV/div
CH2: OUTPUT AFTER BACKMATCH RESISTOR, 200mV/div
PIN NAME FUNCTION
1VCCPower-Supply Input
2 FSEL0 Frequency-Select Input. LSB for bandwidth selection.
3 Y/G_IN Video Input Channel 1
4 Pb/B_IN Video Input Channel 2
5 Pr/R_IN Video Input Channel 3
Bias Control Digital Input. Enables voltage bias for the Pb/B and Pr/R channels. Force BIAS low to
6 BIAS
enable voltage bias and disable the input clamps. Force BIAS high to disable voltage bias and enable
the input clamps.
7, 14 N.C. No Connection. Not internally connected.
8 GND Ground
9 SHDN
Shutdown Digital Input. SHDN places the device into a powered-down state. Force SHDN low to enable
shutdown. Force SHDN high for normal operation.
10 Pr/R_OUT Video Output Channel 3
11 Pb/B_OUT Video Output Channel 2
12 Y/G_OUT Video Output Channel 1
13 FSEL1 Frequency Select Input. MSB for bandwidth selection.
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
8 _______________________________________________________________________________________
Detailed Description
The MAX11508/MAX11509 integrated filters offer 3
channels of SD, PS, or HD video, and include a bypass
mode useful for high-bandwidth 1080p and RGB video
signals. The MAX11508 6th-order lowpass filters provide
-3dB bandwidths of 9MHz (SD), 16MHz (PS), 33MHz
(HD), and 60MHz (BP). The MAX11509 6th-order lowpass filters provide -3dB bandwidths of 10MHz (SD),
17MHz (PS), 34MHz (HD), and 60MHz (BP).
Two control inputs, FSEL0 and FSEL1, select the filter
mode for all filters (Table 1). Input bias circuitry on 2 filter channels can be enabled through the BIAS input to
offer simple connection to bipolar video signals such as
C, Pb, and Pr. Shutdown mode reduces device current
to 1µA (typ) and is enabled by forcing SHDN low.
Figure 1 shows a simplified block diagram of the
MAX11508/MAX11509.
The MAX11508 provides a flat passband response and
the MAX11509 provides a +0.8dB high-frequency
boost at 5MHz (SD), 8.5MHz (PS), and 20MHz (HD) to
help with system rolloff. No frequency boost is included
in bypass mode. Typical voltage waveforms are shown
in Figures 2 and 3.
Inputs
Transparent Clamps
All inputs feature transparent clamps to allow either ACor DC-coupling of the inputs. The clamp remains inactive while the input signal is above ground, offering true
DC input coupling. When the signal goes below
ground, as is the case when it is AC-coupled, the
clamp sets the sync tip close to the ground level.
Input Coupling
The choice of AC- or DC-coupling the input depends
on the video source. Many DACs have a current output
and are terminated to ground with a resistor; such signals are conveniently DC-coupled. Use AC-coupling
when the DC level of the video signal is unknown or
outside the specified input range of the MAX11508/
MAX11509, such as SCART or VCC-terminated DAC
outputs. A bias network within 2 channels of the
MAX11508/MAX11509, for use with bipolar signals,
connects to the input node when BIAS is forced low.
Figures 4 and 5 show how the bias network operates.
DC-Coupled Inputs
When the input is DC-coupled, the voltage must remain
above zero, but not to exceed 1.4V (typ).
AC-Coupling and BIAS
When the input is AC-coupled, the transparent clamps
are active and set the lowest point of the signal at
ground. This is appropriate for unipolar signals such as
CVBS, Y, R, G, or B, with sync pulses (Figure 4). Force
BIAS high when coupling unipolar signals.
For bipolar signals, such as Pb and Pr, a bias network is
provided within the MAX11508/MAX11509 for inputs
Pb/B_IN and Pr/R_IN. Force BIAS low to connect the bias
network to these inputs (Figure 5). The internal network
biases AC-coupled inputs to a fixed DC voltage, typically
0.59V, to ensure that the transparent clamp remains off.
Table 1. Frequency-Selection Truth Table
CONTROL INPUTS
FILTER -3dB FREQUENCY (MHz)
FSEL1 FSEL0 MAX11508 MAX11509
OPERATING MODE
0 0 9 10 Standard definition
0 1 16 17 Progressive scan
1 0 33 34 High definition
1 1 60 60 Bypass
SHDN
FSEL0
FSEL1
BIAS
Y/G_IN
Pb/B_IN
Pr/R_IN
TRANSPARENT
CLAMP
9MHz/16MHz/33MHz/60MHz
(10MHz/17MHz/34MHz/60MHz)
9MHz/16MHz/33MHz/60MHz
(10MHz/17MHz/34MHz/60MHz)
9MHz/16MHz/33MHz/60MHz
(10MHz/17MHz/34MHz/60MHz)
Y/G_OUT
Pb/B_OUT
Pr/R_OUT
V
CC
GND
BIAS
NETWORK
MAX11508
MAX11509
6dB
TRANSPARENT
CLAMP
6dB
TRANSPARENT
CLAMP
6dB
Figure 1. Block Diagram
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
_______________________________________________________________________________________ 9
Figure 2. Typical AC-Coupled Signal
INPUT
OUTPUT
MAX11508
MAX11509
OUTPUT SIGNAL
1.19V
2.59V
0.59V
INPUT SIGNAL
0.32V
1.02V
0.02V
0.00V
SD SYNC SIGNAL NOT SHOWN FOR CLARITY.
Figure 3. Typical DC-Coupled Signal
1.0V
0.3V
0.0V
SD SYNC SIGNAL NOT SHOWN FOR CLARITY.
INPUT SIGNAL
INPUT
MAX11508
MAX11509
OUTPUT
2.55V
1.15V
0.55V
OUTPUT SIGNAL
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
10 ______________________________________________________________________________________
Figure 4. Simple AC-Coupling and BIAS Control for Unipolar Signals (CVBS, Y, R, G, B)
Pr/R_IN
BIAS
0.1µF
V
CC
ENCODER
Pb/B_IN
0.59V
0.59V
MAX11508
MAX11509
DAC
0.1µF
DAC
Figure 5. AC-Coupling and BIAS Control for Bipolar Signals (C, Pb, Pr)
ENCODER
0.1µF
0.1µF
Pb/B_IN
V
CC
Pr/R_IN
BIAS
DAC
DAC
MAX11508
MAX11509
V
CC
0.59V
0.59V
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
______________________________________________________________________________________ 11
Filters
The MAX11508 filter characteristic provides excellent
time-domain response with low overshoot and guarantees minimal attenuation in the passband. The
MAX11509 filters offer a small gain peaking response to
counter system rolloff.
Select filter frequency with inputs FSEL0 and FSEL1, as
shown in Table 1.
Standard-Definition (SD) Filters
The MAX11508 SD filters have a 9MHz (typ) -3dB frequency, while the MAX11509 SD filters offer a 10MHz
(typ) -3dB frequency and a +0.8dB high-frequency
boost at 5MHz (typ). Both devices have a stopband
attenuation of +48dB (typ) at 27MHz.
Progressive-Scan (PS) Filters
The MAX11508 PS filters have a 16MHz (typ) -3dB frequency, while the MAX11509 PS filters offer a 17MHz
(typ) -3dB frequency and a +0.8dB high-frequency
boost at 8.5MHz (typ). Both devices have a stopband
attenuation of +44dB (typ) at 54MHz.
High-Definition (HD) Filters
The MAX11508 HD filters have a 33MHz (typ) -3dB frequency, while the MAX11509 HD filters offer a 34MHz
(typ) -3dB frequency and a +0.8dB high-frequency
boost at 20MHz (typ). Both devices have a stopband
attenuation of +45dB (typ) at 74.25MHz.
Bypassing the Filters
The MAX11508/MAX11509 filter bypass circuitry offers
a 60MHz (typ) -3dB frequency. Bypassed filters offer no
gain peaking.
Output Buffer
The MAX11508/MAX11509 feature output buffers with
+6dB gain that drive a standard 150Ω video load at
2V
P-P
. A typical load consists of a 75Ω backmatch
resistor, an optional 220µF or larger coupling capacitor,
and a 75Ω termination resistor.
An offset of 550mV is added at the output. The offset
ensures that the blanking level on the output is less
than 1V after the backmatch resistor, thus meeting digital TV specifications allowing the devices to drive video
loads directly without using costly AC-coupling capacitors. The basic output voltage equation of all filters is:
V
OUT
= (2 x VIN) + 0.55V
Typical voltage waveforms are shown in Figures 2 and 3.
Shutdown
Forcing digital input SHDN low places the MAX11508/
MAX11509 into low-power shutdown mode. In shutdown, the device consumes only 1µA (typ), and the
outputs are internally connected to GND through
1.58kΩ resistors. In shutdown, the input clamps are disabled and the inputs are internally connected to GND
through 350kΩ resistors. When shutdown is forced low
while BIAS is low, the bias network remains active, but
the bias voltage changes from its nominal 0.59V to
0.475V (typ).
Applications Information
Output Considerations
DC- or AC-couple the MAX11508/MAX11509 outputs.
These devices, with +6dB gain, are typically connected
to a 75Ω series backmatch resistor followed by a video
cable. Choose an AC-coupling capacitor value that
ensures that the lowest frequency content in the video
signal is passed and the field-time distortion is kept
within desired limits when using an AC connection. The
selection of this value is a function of the input impedance, and more importantly, the input leakage of the
circuit being driven. Common industry practice is to
use a 220µF or larger capacitor.
The MAX11508/MAX11509 outputs are fully protected
against short circuits to ground. The short-circuit protection circuitry limits the output current to 75mA (typ)
per output. Shorting more than one output to ground
simultaneously may exceed the maximum package
power dissipation.
PCB Layout Recommendations
Connect the power and ground traces to large copper
areas to enhance power dissipation. Bypass VCCto
GND with 0.1µF and 1.0µF capacitors. Place the 0.1µF
capacitor closest to VCC. Use surface-mount capacitors for their low inductance. Place traces carrying
video signals appropriately to avoid mutual coupling.
When inputs are AC-coupled, place the capacitors as
close as possible to the device and keep traces short
to minimize parasitic capacitance and inductance.
Refer to the MAX11508/MAX11509 evaluation kit data
sheet for PCB layout.
Chip Information
PROCESS: BiCMOS
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
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.
12
____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Typical Operating Circuit
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages
.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
14 TSSOP U14+1
21-0066
+5V
DAC
75Ω
DAC
75Ω
DAC
75Ω
1.0µF
Y/G_IN
Pb/B_IN
BIAS
SHDN
Pr/R_IN
FSEL1
FSEL0
V
CC
MAX11508
MAX11509
GND
0.1µF
AC-COUPLING
CAPACITORS ARE OPTIONAL.
Y/G_OUT
Pb/B_OUT
Pr/R_OUT
75Ω
75Ω
75Ω
220µF
220µF
220µF
75Ω VIDEO
CABLE
75Ω
75Ω
75Ω
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