Rainbow Electronics MAX9671 - Manual

General Description
The MAX9670/MAX9671 dual SCART matrices route
audio and video signals between a set-top box
decoder chip and two external SCART connectors
under I
2 C control. Operating from a 3.3V supply and a
12V supply, the MAX9670/MAX9671 consume 70mW
during quiescent operation and 471mW during average
operation when driving typical signals into typical
loads. Video input detection, video load detection, and
a 2.5mW standby mode facilitate the design of intelli-
gent, low-power set-top boxes.
The MAX9670/MAX9671 audio section contains a
buffered crosspoint to route audio inputs to audio out-
puts and programmable volume control from -62dB to
0dB in 2dB steps. The DirectDrive
® output amplifiers
create a 2V
RMS
full-scale audio signal biased around
ground, eliminating the need for bulky output capaci-
tors and reducing click-and-pop noise. The zero-cross
detection circuitry also further reduces clicks and pops
by enabling audio sources to switch only during a zero-
crossing. The MAX9671 offers TV left and right audio
inputs.
The MAX9670/MAX9671 video section contains a
buffered crosspoint to route video inputs to video out-
puts. The standard-definition video signals from the set-
top box decoder chip are lowpass filtered to remove
out-of-band artifacts.
The MAX9670/MAX9671 also support slow-switching
and fast-switching signals. An interrupt signal from the
MAX9670/MAX9671 informs the microcontroller when
the system status has changed.
Applications
Set-Top Boxes
TVs
DVD Players
Features
♦ 70mW Quiescent Power Consumption
♦ 2.5mW Standby Mode Consumption
♦ Programmable Audio Gain Control of -62dB to
0dB (TV Audio Outputs)
♦ Clickless, Popless, DirectDrive Audio
♦ Video Input and Video Load Detection
♦ Video Reconstruction Filter with 10MHz Passband
and 52dB Attenuation at 27MHz
♦ 3.3V and 12V Supply Voltages
MAX9670/MAX9671
Low-Power Audio/Video Switch with Audio
Volume Control for Dual SCART Connectors
________________________________________________________________ Maxim Integrated Products 1
19-4653; Rev 0; 7/09
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
Ordering Information
PART TEMP RANGE
PIN-
PACKAGE
TV R+L
AUDIO
INPUTS
MAX9670CTL+ 0°C to +70°C 40 TQFN-EP* No
MAX9671CTH+ 0°C to +70°C 44 TQFN-EP* Yes
+ Denotes a lead(Pb)-free/RoHS-compliant package.
* EP = Exposed pad.
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
Typical Application Circuit appears at end of data sheet.
I 2 C INTERFACE
REGISTERS AND
ACTIVITY
MONITOR
VIDEO FILTERS AND
CROSSPOINT
AUDIO CROSSPOINT
WITH DIRECTDRIVE
OUTPUTS, VOLUME
CONTROL
SLOW SWITCHING
FAST SWITCHING
CHARGE PUMP
V 12 V AUD V VID
12V 3.3V 3.3V
EP GNDVID
µC
VIDEO
ENCODER
STEREO
AUDIO
DAC
I 2 C
INTERRUPT
OUTPUT
RGB, Y/C, CVBS
SINGLE-ENDED R/L
STEREO AUDIO
RGB, Y/C, CVBS
CVBS
L/R AUDIO
(MAX9671 ONLY)
SLOW SWITCHING
Y/C, CVBS
RGB, Y/C, CVBS
L/R AUDIO
SLOW SWITCHING
STB CHIP
TV
SCART
VCR
SCART
FAST SWITCHING
FAST SWITCHING
L/R AUDIO
(MAX9670 ONLY)
MAX9670/MAX9671
System Block Diagram