View MAX7438_295171.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-2857; Rev 0; 4/03
KIT ATION EVALU E AILABL AV
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND
General Description
The MAX7438/MAX7439 three-channel standard definition video reconstruction filters include a back-porch clamp that sets the output blanking level of the video signal to ground. Each channel of the MAX7438/ MAX7439 combines a lowpass filter with adjustable high-frequency boost levels and an output buffer capable of driving two standard 150 video loads. The blanking level of the output video signal on each channel is clamped to ground, eliminating the need for large AC-coupling output capacitors. Direct input coupling circuitry eliminates the need for AC-coupling input capacitors. This DC-in/DC-out architecture results in extremely low line-time distortion. The MAX7438/ MAX7439 are ideal for antialiasing and DAC smoothing in digital video devices such as STBs, DVDs, PVRs, and hard disk recorders. The MAX7438/MAX7439 operate from 5V dual supplies. The three-channel MAX7438/MAX7439 are ideal for Y, Pb, Pr, and RGB component video signals, three composite video signals, and also Y/C plus CVBS video signals. Each filter channel achieves 60dB of attenuation at 27MHz and a maximally flat passband from DC to 5MHz. The MAX7438 offers an internal gain of +2V/V, while the MAX7439 offers a gain of +3V/V.
Features
o Back-Porch of Video Output Signal Clamped to Ground o Eliminates Input/Output AC-Coupling Capacitors o 0.1% Line-Time Distortion o Stopband: 55dB at 27MHz o Passband: 0.8dB out to 5MHz o Diff Gain = 0.05%, Diff Phase = 0.05 Degrees o Output Clamped to Ground with Loss of Input o Each Output Drives Two 150 Video Loads o Up to 2dB of High-Frequency Boost Control o Ideal for CVBS, Y/C (S-Video), and RGB (Y, Pb, Pr) Outputs for NTSC, PAL, and SDTV o Filter Bypass Mode o Small 20-Pin 5mm 5mm Thin QFN Package
MAX7438/MAX7439
Ordering Information
PART MAX7438ETP MAX7439ETP TEMP RANGE -40C to +85C -40C to +85C PIN-PACKAGE 20 Thin QFN-EP* 20 Thin QFN-EP*
Applications
Set-Top Boxes/HDR/DVD Game Consoles Camcorders Composite, Component, S-Video Output for NTSC, PAL, SDTV
*EP = Exposed paddle Pin Configuration appears at end of data sheet.
Functional Diagram
ENCODER DAC1 IN1 LOWPASS FILTER BACK-PORCH DETECTOR IN2 LOWPASS FILTER
GAIN/LEVEL SHIFT
OUT1 75
Z0 = 75 Z0 = 75 75
75 OUT2 75
75
DAC2
GAIN/LEVEL SHIFT
Z0 = 75 Z0 = 75 75
MAX7438 MAX7439
DAC3 IN3 LOWPASS FILTER HIGH-FREQUENCY BOOST CONTROL/ BYPASS
GAIN/LEVEL SHIFT
75 OUT3 75
75
Z0 = 75 Z0 = 75 75
HFB1 HFB2 HFB3
75 BIAS GENERATOR GND EXT 10k
75
VCC = +5V VSS = -5V
________________________________________________________________ Maxim Integrated Products
1
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.
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND MAX7438/MAX7439
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..............................................................-0.3V to +6V VSS to GND...............................................................-6V to +0.3V OUT_ to GND ........................................................-2.5V to +3.5V All Other Pins to GND ......................(VSS - 0.3V) to (VCC + 0.3V) Maximum Current into Any Pin .........................................50mA Continuous Power Dissipation (TA = +70C) 20-Pin 5mm x 5mm Thin QFN (derate 20.8mW/C above +70C)...........................................................1666.7mW Operating Temperature Range ...........................-40C to +85C Storage Temperature Range .............................-65C to +150C Junction Temperature ......................................................+150C Lead Temperature (soldering, 10s) .................................+300C
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 5%, VSS = -5V 5%, REXT = 10k 1%, RHFB_-1 = 15k 1%, RHFB_-2 = 1k 1%, no boost, ROUT = 75, COUT = 0 to 20pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.)
PARAMETER Passband Response Stopband Attenuation HF Boost Step Size ASB SYMBOL CONDITIONS f = 100kHz to 4.2MHz, no HF boost f = 100kHz to 5MHz, no HF boost f = 27MHz, relative to 100kHz f = 4.2MHz Bypass No boost HFB_ Voltage Range VHFB_ Boost 1 Boost 2 Boost 3 Boost 4 5-step modulated staircase MAX7438, VIN = 1VP-P MAX7439, VIN = 670mVP-P MAX7438, VIN = 1VP-P MAX7439, VIN = 670mVP-P MAX7438, VIN = 700mVP-P MAX7439, VIN = 460mVP-P 68 0 280 670 1360 2250 3500 0.05 0.05 0.05 0.05 0.2 0.2 75 12 2 0.1 0.2 30 MIN -0.6 -0.8 40 60 0.45 50 360 850 1700 2750 VCC 0.5 % 0.5 0.5 Degrees 0.5 0.5 % 0.5 dB ns ns % % mV TYP MAX +0.6 +0.8 UNITS dB dB dB
Differential Gain
dG
Differential Phase
d
5-step modulated staircase
Total Harmonic Distortion
THD
f = 100kHz to 5MHz, VIN = 0.7VP-P
Signal-to-Noise Ratio Group Delay Deviation Group Delay Matching Line-Time Distortion Field-Time Distortion
SNR tG tG(MATCH) HDIST VDIST
Output signal (2VP-P) to P-P noise, f = 100Hz to 5MHz Deviation from 100kHz to 3.58(4.43)MHz f = 100kHz 18s, 100 IRE bar 130 lines, 18s, 100 IRE bar
2
_______________________________________________________________________________________
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V 5%, VSS = -5V 5%, REXT = 10k 1%, RHFB_-1 = 15k 1%, RHFB_-2 = 1k 1%, no boost, ROUT = 75, COUT = 0 to 20pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.)
PARAMETER Clamp Accuracy Clamp Settling Time Low-Frequency Gain Low-Frequency Gain Matching Input Voltage Range Output Voltage Range Channel-to-Channel Crosstalk Output Short-Circuit Current Input Leakage Current at IN_ Input Leakage Current at HFB_ Input Resistance Supply Voltage Range Supply Current Power-Supply Rejection Ratio VCC VSS ICC ISS PSRR VCC = +5.25V, no load VSS = -5.25V, no load VIN = 100mVP-P, f = 0 to 3.5MHz VOUT XTALK ISC IIN_ IHFB_ Bypass mode, boost 1 to boost 3 Boost 4 500 4.75 -4.75 110 110 30 5.25 -5.25 160 160 tG SYMBOL CONDITIONS Output blanking level relative to GND Back porch within the specified clamp accuracy Gain at 100kHz MAX7438 MAX7439 5.5 9 6 9.54 MIN -55 TYP MAX +55 50 6.5 10 +5 -0.5 -0.8 -60 50 1 5 0.2 30 +1.8 +1.8 UNITS mV Lines dB % V V dB mA A A k V mA dB
MAX7438/MAX7439
Channel-to-channel gain matching, f = 100kHz THD < 0.5% f = 5MHz Channel-to-channel crosstalk, f = 5MHz OUT_ shorted to GND or VCC
Typical Operating Characteristics
(VCC = +5V, VSS = -5V, ROUT_ = 150, REXT = 10k, no boost, TA = +25C, unless otherwise noted.)
MAX7438 AMPLITUDE vs. FREQUENCY
MAX7438/9 toc01
MAX7439 AMPLITUDE vs. FREQUENCY
MAX7438/9 toc02
MAX7438 PASSBAND AMPLITUDE vs. FREQUENCY
2.0 1.5 1.0 GAIN (dB) 0.5 0 -0.5 -1.0 -1.5 -2.0 BOOST 1 NO BOOST BOOST 4 BOOST 3 BOOST 2
MAX7438/9 toc03
10 0 -10 -20 GAIN (dB) -30 -40 -50 -60 -70 -80 NORMALIZED TO 0dB 0.1 1 10
10 0 -10 -20 GAIN (dB) -30 -40 -50 -60 -70 -80 NORMALIZED TO 0dB
2.5
NORMALIZED TO 0dB -2.5 10 100 0.1 1 FREQUENCY (MHz) 10
100
0.1
1
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
3
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND MAX7438/MAX7439
Typical Operating Characteristics (continued)
(VCC = +5V, VSS = -5V, ROUT_ = 150, REXT = 10k, no boost, TA = +25C, unless otherwise noted.)
MAX7439 PASSBAND AMPLITUDE vs. FREQUENCY
MAX7438/9 toc04
MAX7438 CHANNEL RESPONSE (BYPASS MODE)
MAX7438/9 toc05
MAX7439 CHANNEL RESPONSE (BYPASS MODE)
MAX7438/9 toc06
2.5 2.0 1.5 1.0 GAIN (dB) 0.5 0 -0.5 -1.0 -1.5 -2.0 NORMALIZED TO 0dB -2.5 0.1 1 FREQUENCY (MHz) BOOST 1 NO BOOST BOOST 4 BOOST 3 BOOST 2
10 0 -10 GAIN (dB) -20 -30 -40 -50 NORMALIZED TO 0dB 0.1 1 10
10 0 -10 GAIN (dB) -20 -30 -40 -50 NORMALIZED TO 0dB 0.1 1 10
10
100
100
FREQUENCY (MHz)
FREQUENCY (MHz)
MAX7438 GROUP DELAY vs. FREQUENCY
MAX7438/9 toc07
MAX7439 GROUP DELAY vs. FREQUENCY
MAX7438/9 toc08
DIFFERENTIAL GAIN
0.00 -0.04 0.01 -0.02 -0.04 -0.01 0.2 DIFFERENTIAL GAIN (%) 0.1 0.0 -0.1 -0.2 -0.3
MAX7438/9 toc09
140 120 100 80 60 40 20 0 0.1 1 FREQUENCY (MHz)
140 120 100 80 60 40 20 0
0.3
GROUP DELAY (ns)
10
GROUP DELAY (ns)
0.1
1 FREQUENCY (MHz)
10
1ST
2ND
3RD
4TH
5TH
6TH
DIFFERENTIAL PHASE
MAX7438/9 toc10
2T RESPONSE
MAX7438/9 toc11
12.5T RESPONSE
MAX7438/9 toc12
0.3 0.00 0.03 DIFFERENTIAL PHASE (DEGREES) 0.2 0.1 0.0 -0.1 -0.2 -0.3 1ST 2ND 3RD 4TH 5TH 6TH 0.03 -0.02 -0.01 -0.02
IN_ 200mv/div
IN_ 200mv/div
OUT_ 200mv/div 200ns/div
OUT_ 200mv/div 400ns/div
4
_______________________________________________________________________________________
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND
Typical Operating Characteristics (continued)
(VCC = +5V, VSS = -5V, ROUT_ = 150, REXT = 10k, no boost, TA = +25C, unless otherwise noted.)
PASSBAND CHANNEL-TO-CHANNEL CROSSTALK vs. FREQUENCY
MAX7438/9 toc15
MAX7438/MAX7439
SUPPLY CURRENT VS. TEMPERATURE
MAX7438/9 toc13
OUTPUT SOURCE IMPEDANCE vs. FREQUENCY
3.5 OUTPUT IMPEDANCE () 3.0 2.5 2.0 1.5 1.0 0.5 0 -100 0.1 1 FREQUENCY (MHz) 10 0.1
MAX7438/9 toc14
140 105 SUPPLY CURRENT (mA) 70 35 0 -35 -70 -105 -140 -40 -15 10 35 60 ISS VCC = +5V VSS = -5V ICC
4.0
0
-20 CROSSTALK (dB)
-40
-60
-80
85
1 FREQUENCY (MHz)
10
TEMPERATURE (C)
BACK-PORCH LEVEL OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX7438/9 toc16
BACK-PORCH CLAMP VOLTAGE vs. TEMPERATURE
BACK-PORCH CLAMP VOLTAGE (mV)
MAX7438/9 toc17
100 75 OUTPUT VOLTAGE (mV) 50 25 0 -25 -50 -75 -100 -0.2 0.1 0.4 0.7 1.0 1.3
50
25
0
-25
-50 1.6 -40 -15 10 35 60 85 INPUT VOLTAGE (V) TEMPERATURE (C)
_______________________________________________________________________________________
5
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND MAX7438/MAX7439
Pin Description
PIN 1, 4, 7, 10, 11, 13, 15, 19 2 3 5 6 8 9 12 14 16 17 18 20 -- NAME GND IN1 HFB1 OUT1 VCC OUT2 VSS OUT3 HFB3 IN3 HFB2 IN2 EXT EP Ground Channel 1 Video Input Channel 1 High-Frequency Boost and Filter Bypass Control Input. Connect external resistors to HFB1 for high-frequency boost and filter bypass control. See Table 1. Channel 1 Video Output +5V Power Input Channel 2 Video Output -5V Power Input. Connect the backside exposed pad to VSS. Channel 3 Video Output Channel 3 High-Frequency Boost and Filter Bypass Control Input. Connect external resistors to HFB3 for high-frequency boost and filter bypass control. See Table 1. Channel 3 Video Input Channel 2 High-Frequency Boost and Filter Bypass Control Input. Connect external resistors to HFB2 for high-frequency boost and filter bypass control. See Table 1. Channel 2 Video Input External Bias Resistor. Connect a 10k resistor from EXT to GND. Exposed Paddle. Connect to VSS. Do not connect to GND. FUNCTION
Table 1. External Resistor Values for Bypass Mode and High-Frequency Boost Control
MODE Bypass No boost Boost 1 Boost 2 Boost 3 Boost 4 RHFB_-1 (k) Open 15 11.3 16.5 11.3 4.42 RHFB_-2 (k) 0 1 2 7.32 11.3 18.2 VHFB_ (V) (VCC = 5V) 0 0.318 0.758 1.53 2.5 4.027 NOMINAL BOOST (dB)/ BYPASS (MAX7438) Bypass 0 0.5 1.0 1.5 2.0 NOMINAL BOOST (dB)/ BYPASS (MAX7439) Bypass 0 0.75 1.5 2.25 3.0
Detailed Description
Filter
Filter Response The MAX7438/MAX7439 reconstruction filters consist of three separate lowpass filters with Butterworth-type response. The filter features a maximally flat passband for NTSC and PAL bandwidths, while maintaining good group delay characteristics. The stopband offers excellent attenuation at frequencies of 27MHz and above (see the Typical Operating Characteristics section).
6
The autotrimming circuit digitally controls the corner frequency to maintain the frequency characteristics over process and temperature. High-Frequency Boost The high-frequency boost compensates for signal degradation and roll-off in the signal path prior to the MAX7438/MAX7439 to increase image sharpness. Program the level of high-frequency boost for each channel by selecting the corresponding external resistor values (R HFB_-1 and R HFB_-2 , as shown in the Typical Operating Circuit section) given in Table 1. The
_______________________________________________________________________________________
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND MAX7438/MAX7439
ACTIVE VIDEO FRONT PORCH BACK PORCH
BLACK LEVEL (SETUP) BLANK LEVEL
COLOR BURST
H-SYNC TIP
Figure 1. Standard Video Signal
external resistors form a voltage-divider between VCC and GND. The values in the fourth column (VHFB_ (V)) are calculated using the following equation: VHFB_ = VCC x RHFB_-2 / (RHFB_-1 + RHFB_-2) where VCC = 5V. Apply an external voltage to HFB_ in place of RHFB_-1 and R HFB_-2 as an alternative. See the Electrical Characteristics section. Filter boost modes can also be controlled from a microprocessor. See the Applications Information section. Filter Bypass The MAX7438/MAX7439 offer selectable filter bypassing that allows any of the video inputs to be filtered or unfiltered. Select the filter bypass mode for a given channel by setting the corresponding values for RHFB_-1 and RHFB_-2 according to Table 1.
system that provides the appropriate DC-level shift in the filter channel to clamp the output to ground. The back-porch clamp to ground eliminates the need for large output-coupling capacitors that can introduce unwanted line-time distortion (tilt), cost, and board space. This feedback network and the on-chip capacitors introduce a finite settling time (50 lines max) after power-up or any dramatic shift in input voltage (see the Electrical Characteristics section). Channel 1 requires a video signal with sync information (CVBS, Y, or G), since the other two channels are clamped from channel 1. In the absence of a sync on channel 1, the circuit forces all outputs actively and continuously to ground.
Applications Information
Power-Supply Bypassing and Layout
The MAX7438/MAX7439 operate from dual 5V supplies. Bypass VCC and VSS to GND with 0.1F capacitors in parallel with 1F capacitors. Place the 0.1F capacitors as close to the power inputs as possible. Since EXT is a sensitive input, place REXT close to the device to avoid signals coupling into EXT. Do not route any input, output, or dynamic signal near this pin and the accompanying trace. Note: The exposed paddle is electrically connected to VSS. Do not connect the exposed paddle to ground. Refer to the MAX7438 EV kit for layout examples, as well as a proven PC board layout example.
Output Buffer
The output buffer is able to drive two standard 150 video loads with a 2VP-P signal. The MAX7438 output buffer has a preset gain of 2V/V, and the MAX7439 output buffer has a gain of 3V/V. The MAX7439 is ideal for a DAC output whose voltage range is between 0.67V and 1V. Set the DAC output to 0.67V to achieve a 2V/V signal on OUT_.
Back-Porch Clamp
The MAX7438/MAX7439 feature a back-porch clamp to set the output blanking level. This clamp shifts the DC level of the video signal so that the back-porch level is close to ground (see Figure 1). The devices sense the voltage during back porch and feed back into a control
_______________________________________________________________________________________
7
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND MAX7438/MAX7439
Typical Operating Circuit
ENCODER DAC3 RT RHFB2-1 DAC2 RT 10k RHFB2-2 VCC EXT RT VCC RHFB1-1 HFB1 RHFB1-2 IN1 IN2 HFB2 IN3 HFB3 RHFB3-2 RHFB3-1 VCC
DAC1
MAX7438 MAX7439
OUT3 75
Z0 = 75 75 Z0 = 75 75
Z0 = 75 75 Z0 = 75 75 75 1F 0.1F 75
OUT1 VCC OUT2
GND VSS
8
75
0.1F
1F
VCC = +5V
VSS = -5V Z0 = 75 75 Z0 = 75 75 75 75
Microprocessor Control of High-Frequency Boost and Bypass
Use a DAC output to control the bypass and high-frequency boost levels on each channel (see Figure 2). Set the DAC output voltage to the corresponding bypass or boost levels desired (see Table 1).
DAC
MAX7438 MAX7439
HFB_
Figure 2. DAC Control of High-Frequency Boost and Bypass 8 _______________________________________________________________________________________
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND
Pin Configuration
TOP VIEW
HFB2
Chip Information
TRANSISTOR COUNT: 6418 PROCESS: BiCMOS
MAX7438/MAX7439
GND
EXT
IN2
20
19
18
17
GND IN1 HFB1 GND OUT1
1 2 3 4 5
16
IN3
15 14
GND HFB3 GND OUT3 GND
MAX7438 MAX7439
*CONNECT EXPOSED PADDLE TO VSS
13 12 11
OUT2
5mm 5mm THIN QFN
_______________________________________________________________________________________
GND
VCC
GND
VSS
10
6
7
8
9
9
Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND MAX7438/MAX7439
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.)
QFN THIN.EPS
L
REV.
0.15 C A
D2
C L
D
b D2/2
0.10 M C A B
PIN # 1 I.D.
D/2
0.15 C B
k
PIN # 1 I.D. 0.35x45
E/2 E2/2 E (NE-1) X e
C L
E2
k L
DETAIL A
e (ND-1) X e
C L
C L
L
e 0.10 C A 0.08 C
e
C
A1 A3
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE 16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm
APPROVAL DOCUMENT CONTROL NO.
21-0140
C
1 2
COMMON DIMENSIONS
EXPOSED PAD VARIATIONS
NOTES: 1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994. 2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES. 3. N IS THE TOTAL NUMBER OF TERMINALS. 4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE. 5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.25 mm AND 0.30 mm FROM TERMINAL TIP. 6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY. 7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION. 8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS. 9. DRAWING CONFORMS TO JEDEC MO220. 10. WARPAGE SHALL NOT EXCEED 0.10 mm.
PROPRIETARY INFORMATION TITLE:
PACKAGE OUTLINE 16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm
APPROVAL DOCUMENT CONTROL NO. REV.
21-0140
C
2 2
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.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

▲Up To Search▲

Price & Availability of MAX7438

	To Download MAX7438 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .