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参数资料
| 型号： | LTC6908CDCB-2#TRMPBF |
| 厂商： | Linear Technology |
| 文件页数： | 14/16页 |
| 文件大小： | 0K |
| 描述： | IC OSC SILICON 10MHZ 6-DFN |
| 标准包装： | 500 |
| 类型： | 振荡器 - 硅 |
| 频率： | 50kHz ~ 10MHz |
| 电源电压： | 2.7 V ~ 5.5 V |
| 电流 - 电源： | 1.25mA |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 6-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 6-DFN-EP（2x3） |
| 安装类型： | 表面贴装 |
LTC6908-1/LTC6908-2
7
690812fa
IRES (A)
V
RES
=
V
+ –
V
SET
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.1
10
100
1000
690812 F01
1
V+ = 5V
V+ = 3V
TA = 25°C
OPERATIO
U
As shown in the Block Diagram, the LTC6908’s master
oscillator is controlled by the ratio of the voltage between
the V+ and SET pins and the current entering the SET pin
(IMASTER). When the spread spectrum frequency modula-
tion (SSFM) is disabled, IMASTER is strictly determined by
the (V+ – VSET) voltage and the RSET resistor. When SSFM is
enabled, IMASTER is modulated by a ltered pseudorandom
noise (PRN) signal. Here the IMASTER current is a random
value uniformly distributed between (ISET – 10%) and (ISET
+ 10%). In this way the frequency of the master oscillator
is modulated to produce an approximately at frequency
spectrum that is centered at the frequency set by the ISET
current, with a bandwidth equal to approximately 20% of
the center frequency.
The voltage on the SET pin is forced to approximately 1.1V
below V+ by the PMOS transistor and its gate bias volt-
age. This voltage is accurate to ±5% at a particular input
current and supply voltage (see Figure 1). The LTC6908
is optimized for use with resistors between 20k and 400k,
corresponding to output frequencies between 250kHz and
5MHz. Accurate frequencies up to 10MHz (RSET = 10k)
are attainable if the supply voltage is greater than 4V. The
RSET resistor, connected between the V
+ and SET pins,
locks together the (V+ – VSET) voltage and the current ISET.
This allows the parts to attain excellent frequency accuracy
regardless of the precision of the SET pin voltage. The
master oscillation frequency is:
fMASTER = 20MHz 10k/RSET
The master oscillator signal is divided by 2 before driving
the output pins, resulting in the simple formula for the
Figure 3. Output Waveforms for LTC6908-1, LTC6908-2
Figure 2. RSET vs Desired Output Frequency
Figure 1. V+ – VSET Variation with IRES
OUT1
OUT2
OUT1
LTC6908-1 (COMPLEMENTARY)
LTC6908-2 (QUADRATURE)
OUT2
690812 F03
output frequency, fOUT, below (see Figure 2):
fOUT = 10MHz 10k/RSET
When the spread spectrum frequency modulation (SSFM)
is disabled, the frequency fOUT is the nal output fre-
quency. When SSFM is enabled, 0.9 fOUT is the minimum
output frequency and 1.1 fOUT is the maximum output
frequency.
Both outputs are nominally 50% duty cycle. There are 2
possible output congurations for the LTC6908, shown
in Figure 3.
Output Congurations
The only difference between the two versions of the
LTC6908 is the phase relationship between the two outputs.
The LTC6908-1 outputs are 180 degrees out of phase and
the LTC6908-2 outputs are 90 degrees out of phase. These
convenient output options are useful in synchronizing the
clocking of multiple phase switching regulator designs. In
very high current applications, a signicant improvement
DESIRED OUTPUT FREQUENCY (Hz)
10k
R
SET
(
)
100k
1M
10M
100k
1M
10M
690812 F02
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| LTC6908CS6-1 | 制造商:Linear Technology 功能描述:RESISTOR SET SOT-23 OSCILLATOR WITH SPREAD SPECTRUM MODULATION |
| LTC6908CS6-1#PBF | 制造商:Linear Technology 功能描述:Silicon Oscillator 6-Pin TSOT-23 制造商:Linear Technology 功能描述:OSCILLATOR 10MHZ 5.5V TSOT- 制造商:Linear Technology 功能描述:OSCILLATOR, 10MHZ, 5.5V, TSOT-23-6; Operating Mode:-; Frequency:10MHz; Supply Voltage Min:2.7V; Supply Voltage Max:5.5V; Digital IC Case Style:TSOT-23; No. of Pins:6; Clock External Input:Yes; Operating Temperature Min:0C ;RoHS Compliant: Yes |
| LTC6908CS6-1#TR | 制造商:Linear Technology 功能描述:SC-Timing, 2 Phase 10kHz - 10MHz oscillator W/SSFM |
| LTC6908CS6-1#TRM | 制造商:Linear Technology 功能描述:SC-Timing, 2 Phase 10kHz - 10MHz oscillator W/SSFM |
| LTC6908CS6-1#TRMPBF | 功能描述:IC OSC SILICON 10MHZ TSOT23-6 RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 可编程计时器和振荡器 系列:- 标准包装:3,000 系列:- 类型:振荡器 - 晶体 计数:- 频率:- 电源电压:2.3 V ~ 5.5 V 电流 - 电源:1.07mA 工作温度:-30°C ~ 80°C 封装/外壳:SOT-665 包装:带卷 (TR) 供应商设备封装:SS迷你型-5D 安装类型:表面贴装 其它名称:AN8955SSMTXLTR |
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