19-4346; Rev 0; 10/08
KIT
ATION
EVALU
E
L
B
A
IL
AVA
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
Features
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.
♦ Three Selectable 6th-Order 9MHz/16MHz/33MHz
(SD/PS/HD) Filters
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 2VP-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.
♦ ±12kV HBM ESD Protection on Outputs
Applications
Cable and Satellite STB Receivers
HDTV
♦ Bypass Mode for High Bandwidth Signals
♦ Transparent Input Clamp
♦ Output Buffers Drive a Standard 150Ω Video Load
♦ 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
Ordering Information
PART
TEMP RANGE
MAX11508UUD+
0°C to +85°C
14 TSSOP
PIN-PACKAGE
MAX11509UUD+
0°C to +85°C
14 TSSOP
+Denotes a lead-free/RoHS-compliant package.
Pin Configuration
TOP VIEW
+
VCC 1
14 N.C.
FSEL0 2
Y/G_IN 3
DVD Players
Pb/B_IN 4
Personal Video Recorders
Pr/R_IN 5
13 FSEL1
MAX11508
MAX11509
12 Y/G_OUT
11 Pb/B_OUT
10 Pr/R_OUT
DVRs
BIAS 6
9 SHDN
Video-On-Demand
N.C. 7
8 GND
HD Recorders
TSSOP
Typical Operating Circuit appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX11508/MAX11509
General Description
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..............................................................-0.3V to +6V
All Other Pins to GND...................................-0.3V to the lower of
(VCC + 0.3V) and +6V
Continuous Power Dissipation (TA = +70°C)
14-Pin TSSOP (derate 10mW/°C above +70°C) .......796.8mW
Maximum Current into Any Pin Except VCC 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
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, RLOAD = 150Ω to GND, CIN = 0.1µF, TA = 0°C to +85°C, all frequency responses are relative to 100kHz, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
4.75
24
35
mA
5.00
5.25
V
DC CHARACTERISTICS
Supply Current
ICC
Supply Voltage Range
VDD
Input Voltage Range
VIN
Power-Down Current
IPD
Digital Input High Voltage
VIH
Digital Input Low Voltage
VIL
No load
Referenced to GND if DC-coupled
1.4
BIAS = high
1
BIAS = low
15
V
µA
2.0
V
0.8
V
STANDARD-DEFINITION VIDEO
-1dB Bandwidth
f1dB
-3dB Bandwidth
f3dB
Stopband Attenuation
ASB
MAX11508, TA = +25°C
4.5
7.9
MAX11509, TA = +25°C
5
8.6
MAX11508
9.0
MAX11509
10
f = 27MHz
35
5.6
MHz
MHz
48
Low-Frequency Gain
AV
No load
Differential Gain
dG
All channels
0.7
%
Differential Phase
dφ
All channels
0.7
Degrees
THD
VOUT = 1.4VP-P, f = 1MHz, all channels
-60
dB
SNR
2VP-P signal to RMS noise,
f = 100kHz to 4.2MHz
71
dB
Total Harmonic Distortion
Signal-to-Noise Ratio
Group Delay
Power-Supply Rejection Ratio
2
tG
PSRR
6.0
dB
6.6
dB
f = 4.5MHz
59
ns
DC, all channels
50
dB
_______________________________________________________________________________________
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
(VCC = +5V, RLOAD = 150Ω to GND, CIN = 0.1µF, TA = 0°C to +85°C, all frequency responses are relative to 100kHz, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX11508, TA = +25°C
9
13.5
MAX11509, TA = +25°C
10
14
MAX
UNITS
PROGRESSIVE-SCAN VIDEO
-1dB Bandwidth
f1dB
-3dB Bandwidth
f3dB
Stopband Attenuation
ASB
Low-Frequency Gain
AV
MAX11508
16
MAX11509
17
f = 54MHz
MHz
MHz
44
5.6
6.0
dB
6.6
dB
Total Harmonic Distortion
THD
VOUT = 1.4VP-P, f = 7MHz
-55
dB
Signal-to-Noise Ratio
SNR
2VP-P signal to RMS noise,
f = 100kHz to 15MHz
66
dB
f = 10MHz
47
ns
Group Delay
tG
HIGH-DEFINITION VIDEO
-1dB Bandwidth
f1dB
-3dB Bandwidth
f3dB
Stopband Attenuation
Low-Frequency Gain
Total Harmonic Distortion
Signal-to-Noise Ratio
Group Delay
ASB
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
f = 74.25MHz
45
AV
THD
SNR
tG
5.4
6.0
MHz
MHz
dB
6.6
dB
VOUT = 1.4VP-P, f = 10MHz
-55
VOUT = 1.4VP-P, f = 15MHz
-50
VOUT = 1.4VP-P, f = 22MHz
-40
2VP-P signal to RMS noise,
f = 100kHz to 30MHz
65
dB
f = 20MHz
25
ns
60
MHz
dB
BYPASS VIDEO (Note 2)
-3dB Bandwidth
f3dB
Low-Frequency Gain
AV
5.4
6.0
6.6
dB
Total Harmonic Distortion
THD
VOUT = 1.4VP-P, f = 22MHz
-40
dB
Signal-to-Noise Ratio
SNR
2VP-P signal to RMS noise,
f = 100kHz to 30MHz
65
dB
Note 1: All devices are 100% production tested at TA = +25°C.
Note 2: Output AC-coupled with 220µF into 150Ω to GND.
_______________________________________________________________________________________
3
MAX11508/MAX11509
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VCC = 5V, RL = 150Ω to GND, output DC-coupled, TA = +25°C, unless otherwise noted.)
0
10
MAX11508 toc02
7
MAX11508 toc01
10
MAX11509
SD FREQUENCY RESPONSE
MAX11508
SD PASSBAND RESPONSE
5
0
-10
-20
-30
RESPONSE (dB)
RESPONSE (dB)
-10
RESPONSE (dB)
MAX11508 toc03
MAX11508
SD FREQUENCY RESPONSE
3
1
-20
-30
-40
-40
-1
-50
-50
-60
-3
-60
1
10
0.1
100
1
0.1
10
1
10
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX11509
SD PASSBAND RESPONSE
MAX11508
PS FREQUENCY RESPONSE
MAX11508
PS PASSBAND RESPONSE
5
7
0
100
MAX11508 toc06
10
MAX11508 toc04
7
MAX11508 toc05
0.1
5
3
1
RESPONSE (dB)
RESPONSE (dB)
RESPONSE (dB)
-10
-20
-30
3
1
-40
-1
-1
-50
-3
-3
-60
0.1
1
10
0.1
1
10
0.1
100
1
10
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX11509
PS FREQUENCY RESPONSE
MAX11509
PS PASSBAND RESPONSE
MAX11508
HD FREQUENCY RESPONSE
5
100
MAX11508 toc09
0
10
MAX11508 toc08
7
MAX11508 toc07
10
0
-10
-20
-30
RESPONSE (dB)
RESPONSE (dB)
-10
RESPONSE (dB)
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
3
1
-20
-30
-40
-40
-1
-50
-50
0.1
1
10
FREQUENCY (MHz)
4
-60
-3
-60
100
0.1
1
10
FREQUENCY (MHz)
100
0.1
1
10
FREQUENCY (MHz)
_______________________________________________________________________________________
100
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
5
7
MAX11508 toc11
10
MAX11508 toc10
7
MAX11509
HD PASSBAND RESPONSE
MAX11509
HD FREQUENCY RESPONSE
0
MAX11508 toc12
MAX11508
HD PASSBAND RESPONSE
5
3
1
RESPONSE (dB)
RESPONSE (dB)
RESPONSE (dB)
-10
-20
-30
3
1
-40
-1
-1
-50
-3
-3
-60
1
10
100
0.1
1
10
0.1
100
10
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX11508
BP FREQUENCY RESPONSE
MAX11508
BP PASSBAND RESPONSE
MAX11509
BP FREQUENCY RESPONSE
0
5
100
10
MAX11508 toc15
7
MAX11508 toc13
10
0
-10
-20
-30
RESPONSE (dB)
RESPONSE (dB)
-10
RESPONSE (dB)
1
FREQUENCY (MHz)
MAX11508 toc14
0.1
3
1
-20
-30
-40
-40
-1
-50
-50
-60
-3
1
10
0.1
100
1
10
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX11509
BP PASSBAND RESPONSE
MAX11508
SD GROUP DELAY vs. FREQUENCY
120
MAX11508 toc16
7
5
0.1
100
100
120
100
60
40
-20
-20
1
10
FREQUENCY (MHz)
100
40
0
0
0.1
60
20
20
-1
-3
100
80
DELAY (ns)
DELAY (ns)
RESPONSE (dB)
1
10
MAX11509
SD GROUP DELAY vs. FREQUENCY
80
3
1
FREQUENCY (MHz)
MAX11508 toc17
0.1
MAX11508 toc18
-60
0.1
1
10
100
0.1
1
10
100
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
5
MAX11508/MAX11509
Typical Operating Characteristics (continued)
(VCC = 5V, RL = 150Ω to GND, output DC-coupled, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = 5V, RL = 150Ω to GND, output DC-coupled, TA = +25°C, unless otherwise noted.)
20
0
40
20
-40
-20
0.1
1
10
100
0
-20
0
-20
0.1
1
10
0.1
100
10
100
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX11509
HD GROUP DELAY vs. FREQUENCY
MAX11508
BP GROUP DELAY vs. FREQUENCY
MAX11509
BP GROUP DELAY vs. FREQUENCY
20
-20
DELAY (ns)
DELAY (ns)
20
0
0
-40
-40
0.1
1
10
100
0
-20
-20
-40
MAX11508 toc24
40
MAX11508 toc23
MAX11508 toc22
40
20
0.1
1
10
0.1
100
1
10
100
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX11508
SD DIFFERENTIAL GAIN, NTSC
MAX11508
SD DIFFERENTIAL PHASE, NTSC
MAX11509
SD DIFFERENTIAL GAIN, NTSC
0.4
0.2
0
-0.2
-0.4
1.0
0.6
0.4
0.2
0
-0.2
-0.4
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.6
-0.6
-0.8
-0.8
-0.8
-1.0
-1.0
-1.0
2
3
4
STEP
5
6
7
MAX11508 toc27
0.8
DIFFERENTIAL GAIN (%)
0.6
1.0
MAX11508 toc26
0.8
DIFFERENTIAL PHASE (deg)
MAX11508 toc25
1.0
1
1
FREQUENCY (MHz)
40
DELAY (ns)
20
DELAY (ns)
40
40
MAX11508 toc20
60
DELAY (ns)
60
DELAY (ns)
80
MAX11508 toc19
80
6
MAX11508
HD GROUP DELAY vs. FREQUENCY
MAX11509
PS GROUP DELAY vs. FREQUENCY
MAX11508 toc21
MAX11508
PS GROUP DELAY vs. FREQUENCY
DIFFERENTIAL GAIN (%)
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
1
2
3
4
STEP
5
6
7
1
2
3
4
STEP
_______________________________________________________________________________________
5
6
7
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
MAX11509
SD DIFFERENTIAL PHASE, NTSC
MAX11508 toc30
MAX11508 toc29
MAX11508 toc28
1.0
0.8
DIFFERENTIAL PHASE (deg)
MAX11509
SD 2T RESPONSE
MAX11508
SD 2T RESPONSE
0.6
IN
IN
0.4
0.2
CH1
0
CH1
-0.2
-0.4
OUT
OUT
-0.6
-0.8
CH2
CH2
-1.0
1
2
3
4
5
6
STEP
7
200ns/div
CH1: INPUT, 200mV/div
CH2: OUTPUT AFTER BACKMATCH RESISTOR, 200mV/div
200ns/div
CH1: INPUT, 200mV/div
CH2: OUTPUT AFTER BACKMATCH RESISTOR, 200mV/div
Pin Description
PIN
NAME
1
VCC
FUNCTION
Power-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
6
BIAS
Bias Control Digital Input. Enables voltage bias for the Pb/B and Pr/R channels. Force BIAS low to
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.
_______________________________________________________________________________________
7
MAX11508/MAX11509
Typical Operating Characteristics (continued)
(VCC = 5V, RL = 150Ω to GND, output DC-coupled, TA = +25°C, unless otherwise noted.)
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
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.
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.
VCC
Y/G_IN
TRANSPARENT
CLAMP
Y/G_OUT
9MHz/16MHz/33MHz/60MHz
(10MHz/17MHz/34MHz/60MHz)
Inputs
MAX11508
MAX11509
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.
6dB
Pb/B_IN
TRANSPARENT
CLAMP
6dB
Pb/B_OUT
9MHz/16MHz/33MHz/60MHz
(10MHz/17MHz/34MHz/60MHz)
BIAS
BIAS
NETWORK
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,
Pr/R_IN
TRANSPARENT
CLAMP
SHDN
6dB
9MHz/16MHz/33MHz/60MHz
(10MHz/17MHz/34MHz/60MHz)
FSEL1
FSEL0
GND
Figure 1. Block Diagram
Table 1. Frequency-Selection Truth Table
CONTROL INPUTS
FSEL1
FSEL0
0
0
0
1
1
0
1
1
8
FILTER -3dB FREQUENCY (MHz)
MAX11508
MAX11509
9
10
16
17
33
34
60
60
OPERATING MODE
Standard definition
Progressive scan
High definition
Bypass
_______________________________________________________________________________________
Pr/R_OUT
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
MAX11508/MAX11509
2.55V
OUTPUT SIGNAL
MAX11508
MAX11509
INPUT
1.0V
OUTPUT
1.15V
INPUT SIGNAL
0.3V
0.55V
0.0V
SD SYNC SIGNAL NOT SHOWN FOR CLARITY.
Figure 2. Typical AC-Coupled Signal
2.59V
OUTPUT SIGNAL
MAX11508
MAX11509
1.02V
INPUT
OUTPUT
1.19V
INPUT SIGNAL
0.32V
0.59V
0.02V
0.00V
SD SYNC SIGNAL NOT SHOWN FOR CLARITY.
Figure 3. Typical DC-Coupled Signal
_______________________________________________________________________________________
9
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
MAX11508
MAX11509
ENCODER
Pb/B_IN
DAC
0.1µF
VCC
VCC
0.59V
BIAS
0.59V
Pr/R_IN
DAC
0.1µF
Figure 4. Simple AC-Coupling and BIAS Control for Unipolar Signals (CVBS, Y, R, G, B)
MAX11508
MAX11509
ENCODER
Pb/B_IN
DAC
0.1µF
VCC
BIAS
0.59V
0.59V
Pr/R_IN
DAC
0.1µF
Figure 5. AC-Coupling and BIAS Control for Bipolar Signals (C, Pb, Pr)
10
______________________________________________________________________________________
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
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:
VOUT = (2 x VIN) + 0.55V
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 VCC to
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
Typical voltage waveforms are shown in Figures 2 and 3.
______________________________________________________________________________________
11
MAX11508/MAX11509
Filters
MAX11508/MAX11509
Low-Cost, 3-Channel, HD/PS/SD/BP
Video Filters with Buffer
Typical Operating Circuit
+5V
1.0µF
0.1µF
VCC
Y/G_IN
DAC
AC-COUPLING
CAPACITORS ARE OPTIONAL.
75Ω VIDEO
220µF
75Ω
CABLE
Y/G_OUT
75Ω
75Ω
MAX11508
MAX11509
Pb/B_OUT
Pb/B_IN
DAC
75Ω
75Ω
220µF
75Ω
BIAS
SHDN
Pr/R_OUT
Pr/R_IN
DAC
75Ω
75Ω
220µF
75Ω
FSEL1
FSEL0
GND
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
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.
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