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参数资料
| 型号： | LMX2350TM/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | PLL合成/DDS/VCOs |
| 英文描述： | PLL FREQUENCY SYNTHESIZER, 2500 MHz, PDSO24 |
| 封装： | PLASTIC, TSSOP-24 |
| 文件页数： | 8/21页 |
| 文件大小： | 405K |
| 代理商： | LMX2350TM/NOPB |
Programming Description (Continued)
Synchronous Power down Mode
One of the PLL loops can be synchronously powered down
by first setting the power down mode bit HIGH (IF_N[21] = 1)
and then asserting its power down bit (IF_N[22] or RF_N[22]
= 1). The power down function is gated by the charge pump.
Once the power down bit is loaded, the part will go into
power down mode upon the completion of a charge pump
pulse event.
Asynchronous Power down Mode
One of the PLL loops can be asynchronously powered down
by first setting the power down mode bit LOW (IF_N[21] = 0)
and then asserting its power down bit (IF_N[22] or RF_N[22]
= 1). The power down function is NOT gated by the charge
pump. Once the power down bit is loaded, the part will go
into power down mode immediately.
Prescaler select is used to set the RF prescaler. The
LMX2350 is capable of operating from 500 MHz to 1.2 GHz
with the 16/17 prescaler, and 1.2 GHz to 2.5 GHz with the
32/33 prescaler selection. The LMX2352 is capable of oper-
ating from 250 MHz to 500 MHz with the 8/9 prescaler, and
500MHz to 1.2GHz with 16/17 prescaler selection.
4.2.2 5-BIT RF SWALLOW COUNTER DIVIDE RATIO
(RF A COUNTER)
(RF_N[6]-[10])
Swallow Count
RF_NA_CNTR
(A)
43210
0
00000
1
00001
-
-----
31
11111
Note: Swallow Counter Value LMX2350: 0 to 31; LMX2352: 0 to 15
RF_NB_CNTR
≥ RF_NA_CNTR + 2
4.2.3 10-BIT RF PROGRAMMABLE COUNTER DIVIDE
RATIO (RF B COUNTER)
(RF_N[11]-[20])
RF_NB_CNTR
Divide Ratio
9876543210
3
0000000011
4
0000000100
-
----------
1,023
1111111111
Note: Divide ratio: 3 to 1023 (Divide ratios less than 3 are prohibited)
RF_NB_CNTR
≥ RF_NA_CNTR + 2
4.2.4 FRACTIONAL MODULUS ACCUMULATOR (FRAC_CNTR)
(RF_N[2]-[5])
Fractional Ratio (F)
FRAC_CNTR
Modulus 15
Modulus 16
RF_N[5]
RF_N[4]
RF_N[3]
RF_N[2]
0
0000
1/15
1/16
0001
2/15
2/16
0010
-
----
14/15
14/16
1110
N/A
15/16
1111
4.3 PULSE SWALLOW FUNCTION
fvco = [N + F] x [fosc/R]
N=(P x B) + A
F:
Fractional ratio (contents of FRAC_CNTR divided by
the fractional modulus)
fvco: Output frequency of external voltage controlled oscil-
lator (VCO)
B:
Preset divide ratio of binary 10-bit programmable
counter
A:
Preset value of binary 4 or 5-bit swallow counter (0
≤
A
≤ 31 {RF} , 0 ≤ A ≤ 15 {IF} , A+2 ≤ B {RF}, A ≤ B {IF})
fosc: Output frequency of the external reference frequency
oscillator
R:
Preset divide ratio of binary 15-bit programmable ref-
erence counter (3 to 16383)
P:
Preset
modulus
of
dual
modulus
prescaler
(LMX2350:RF P=16 or 32, IF P=8)
(LMX2352:RF P=8 or 16, IF P=8)
4.4 CMOS (Programmable CMOS outputs)
(IF_N[17]-[20])
MSB
LSB
FastLock
TEST
OUT_1
OUT_0
Note: Test bit is reserved and should be set to zero for normal usage.
LMX2350/LMX2352
www.national.com
16
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LMX2350TMX | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Serial-Input Frequency Synthesizer |
| LMX2350TMX/NOPB | 功能描述:IC FREQ SYNTH LOPWR DUAL 24TSSOP RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:PLLatinum™ 标准包装:39 系列:- 类型:* PLL:带旁路 输入:时钟 输出:时钟 电路数:1 比率 - 输入:输出:1:10 差分 - 输入:输出:是/是 频率 - 最大:170MHz 除法器/乘法器:无/无 电源电压:2.375 V ~ 3.465 V 工作温度:0°C ~ 70°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* |
| LMX2352 | 制造商:未知厂家 制造商全称:未知厂家 功能描述: |
| LMX2352SLBX | 功能描述:IC FREQ SYNTH DUAL 24LAMINATECSP RoHS:否 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:PLLatinum™ 标准包装:39 系列:- 类型:* PLL:带旁路 输入:时钟 输出:时钟 电路数:1 比率 - 输入:输出:1:10 差分 - 输入:输出:是/是 频率 - 最大:170MHz 除法器/乘法器:无/无 电源电压:2.375 V ~ 3.465 V 工作温度:0°C ~ 70°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* |
| LMX2352TM | 制造商:Texas Instruments 功能描述:IC, DUAL FREQ SYNTHESIZER 1.2GHZ 24-TSSOP, PLL Type:Frequency Synthesis, Frequen |
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