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参数资料
| 型号： | MAX3580ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 11/20页 |
| 文件大小： | 0K |
| 描述： | IC TUNER TV DIRECT CONV 32TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 类型： | 直接转换电视调谐器 |
| 应用： | 机顶盒 |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 托盘 |
MAX3580
Direct-Conversion TV Tuner
______________________________________________________________________________________
19
RF Tracking Filter
The MAX3580 utilizes two narrowband RF tracking filters,
one for VHF and one for UHF. Each filter is comprised of
a fixed inductor and three digitally controlled variable
capacitors named series, shunt, and parallel capacitors.
The integrated RF tracking filters uses an external induc-
tor between IND1 and IND2 pins to set the filter’s center
frequency. The inductor value must be 68nH ±2% in
order to achieve the corner frequency response. The vari-
able capacitors are factory calibrated to this particular
inductor value. The value of each capacitor is also set to
compensate for process variation of each individual part
and to receive the desired RF channel.
The process variation is factory calibrated by determin-
ing the best capacitor values for three discrete frequen-
cies, which are stored in the on-chip ROM table. Upon
power-up these values (6 bytes total) have to be read
out of the MAX3580 ROM table and stored in the micro-
processor local memory.
When tuning the MAX3580 to a given Rx frequency, the
correct capacitor value has to be calculated using the
following linear formulas and written to the appropriate
registers. This is in addition to programming the PLL
with the desired frequency.
The formulas differ for VHF and UHF bands but are the
same for all three capacitor values. Since the factory
calibration coefficients stored on the MAX3580 can dif-
fer for each capacitor, the calculations have to be exe-
cuted for all three capacitor values separately.
VHF: Capacitor = ROM_value_VHF -
(RX_frequency_in_MHz - 200MHz ) / 10MHz
In other words, the capacitor values to be written to the
MAX3580 decrease 1 count per 10MHz above 200MHz
and increase accordingly below 200MHz.
UHF: Capacitor = ROM_value_UHF_lo -
(ROM_value_UHF_lo - ROM_value_UHF_hi)
x (RX_frequency_in_MHz - 470MHz ) / 390MHz
This means the capacitor values stored in the UHF_lo
entries of the MAX3580 ROM table are the correct values
for 470MHz reception and the UHF_hi values for 860MHz
reception. For any frequency in between, the capacitor
values are obtained by a simple linear interpolation.
Note: When tuning to frequencies above 860MHz
channel center frequency, do not use the formula
above, but rather keep programming the tracking filter
with the coefficients obtained for 860MHz.
Examples: Assuming the MAX3580 ROM table entries
are CSERIES VHF = 8, CSERIES UHF_lo = 15, CSERIES
UHF_hi = 3
208MHz:
CSERIES = 8 - round ( ( 208-200 ) / 10 ) = 7
(floating point division, round to nearest
integer after division)
8 - floor ( ( 208 - 200 + 5) / 10 ) = 7
(all calculations using signed integer values,
truncate result of division)
677MHz:
CSERIES = 15 - round ( (15-3) x (677 - 470) /
390 ) = 9 (floating point division, round to
nearest integer after division) 15 - floor
( ( ( 15-3) x (677-470) + 195 ) / 390 ) = 9
(all calculations using signed integer values,
truncate result of division)
Power-Supply Layout
To minimize coupling between different sections of the
IC, the ideal power-supply layout is a star configuration,
which has a large decoupling capacitor at the central
VCC node. The VCC traces branch out from this node,
with each trace going to separate VCC pins of the
MAX3580. Next to each VCC pin is a bypass capacitor
with a low impedance to ground at the frequency of
interest. Use at least one via per bypass capacitor for a
low-inductance ground connection.
The three ground pins (GND_PLL, GND_CP,
GND_TUNE) must be connected to the ground plane
by separate via holes and must not be directly connect-
ed to the exposed paddle.
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package draw-
ings may show a different suffix character, but the drawing per-
tains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
32 TQFN-EP
T3255-5
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX3580ETJ+ | 功能描述:调谐器 Direct Conversion TV Tuner RoHS:否 制造商:NXP Semiconductors 功能: 噪声系数: 工作电源电压: 最小工作温度: 最大工作温度: |
| MAX3580ETJ+CA1 | 功能描述:调谐器 RoHS:否 制造商:NXP Semiconductors 功能: 噪声系数: 工作电源电压: 最小工作温度: 最大工作温度: |
| MAX3580ETJ+T | 功能描述:调谐器 Direct Conversion TV Tuner RoHS:否 制造商:NXP Semiconductors 功能: 噪声系数: 工作电源电压: 最小工作温度: 最大工作温度: |
| MAX3580ETJ+TW | 制造商:Maxim Integrated Products 功能描述:DIRECT-CONVERSION TV TUNER - Tape and Reel |
| MAX3580ETJ+W | 制造商:Maxim Integrated Products 功能描述:DIRECT-CONVERSION TV TUNER - Rail/Tube |
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