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参数资料
| 型号： | LTC6909IMS#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 模拟信号调理 |
| 英文描述： | SPECIALTY ANALOG CIRCUIT, PDSO16 |
| 封装： | LEAD FREE, PLASTIC, MSOP-16 |
| 文件页数： | 6/22页 |
| 文件大小： | 0K |
| 代理商： | LTC6909IMS#PBF |
LTC6909
14
6909fa
peakelectromagneticradiation(orconduction)isreduced.
Outputripplemaybesomewhatincreased,butitsbehavior
is very much like noise and its system impact is benign.
SUPPLY BYPASSING, SIGNAL CONNECTIONS AND
PCB LAYOUT
Using the LTC6909 in spread spectrum mode naturally
eliminates any concerns for output frequency accuracy
and stability as it is continually hopping to new settings.
In fixed frequency applications however, some attention to
V+ supply voltage ripple is required to minimize additional
output frequency error. Ripple frequency components on
the supply line near the programmed output frequency of
the LTC6909 in excess of 30mVP-P could create an addi-
tional0.2%offrequencyerror.Inapplicationswhereafixed
frequency LTC6909 output clock is used to synchronize
the same switching regulator that provides the V+ supply
to the oscillator, noticeable jitter of the clock may occur if
the ripple exceeds 30mVP-P .
The LTC6909’s accuracy is affected as described above
by supply ripple on the V+A pin only. The V+D pin is es-
sentially insensitive to supply ripple. The V+A pin supplies
the power for the analog section of the LTC6909 and its
current is largely constant for a given RSET resistor value.
The V+D pin supplies the digital section including the out-
put drivers and its current requirement consists mainly of
large bursts that digital circuitry requires when switching.
The peak current required by the output drivers is by far
the largest. The current is mainly dependent on output
capacitive loading and the supply voltage.
Figure 6 shows how to connect the V+A and V+D supply
pinstothepowersupplyaswellasasuggestedPCBlayout.
The PCB layout assumes a two layer board with a ground
plane in the layer beneath the part and 0805 sized passive
components. The PCB layout in Figure 6 is a guide and
need not be followed exactly. However, there are several
items to note from the layout as follows:
1. There should be a ground plane underneath and around
the part. Connect the GND pin to this plane through
multiple (three to four minimum) vias to minimize
inductance.
2. Place the bypass capacitors, C1 and C2, as close to the
V+AandV+Dpinsaspossibletominimizetheinductance
between the capacitor’s lead and the part’s pins.
3. The connection to the V+A and V+D pins to the main
supply should be through a low impedance path. If
the board has a V+ power plane, use it instead of the
top layer connection shown in Figure 6. Use multiple
vias (three to four minimum) at each point to connect
the V+A and V+D pins to the V+ plane to minimize the
inductance.
4.Connectthebypasscapacitors,C1andC2,directlytothe
GND pin using a low inductance path. The connection
from C1 to the GND pin is easily done directly on the top
layer. The C2 path is more difficult but is accomplished
through multiple vias to the ground plane.
5. Connect the RSET resistor directly to the SET pin and
the V+A pin. Connecting the resistor to the V+ supply
through any manner other than directly to the V+A pin
will result greater frequency error.
6. Provide a ground shield around the RSET resistor and
its connections to V+A and SET. The SET pin is a fairly
high impedance point and is susceptible to interference
from noisy signal lines such as the part’s CMOS outputs
OUT1 through OUT8.
7.Routetheoutputsignals,OUT1throughOUT8,awayfrom
the SET pin as soon as possible to minimize coupling.
8.WhenusingtheLTC6909withspreadspectrumdisabled,
an active output is connected to the MOD pin. This is
best done by routing the OUT1 signal under the part
as shown in Figure 6. The ground shield between this
traceandtheRSETresistorisveryimportanttominimize
coupling of the OUT1 signal into the SET pin.
ApplicAtions inForMAtion
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相关代理商/技术参数 |
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| LTC6909IMS-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1 to 8 Output, Multiphase Silicon Oscillator with Spread Spectrum Modulation |
| LTC690C | 制造商:LINER 制造商全称:Linear Technology 功能描述:Microprocessor Supervisory Circuits |
| LTC690CN8 | 功能描述:IC MPU SUPERVISORY CIRCUIT 8-DIP RoHS:否 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 标准包装:1 系列:- 类型:简单复位/加电复位 监视电压数目:1 输出:开路漏极或开路集电极 复位:高有效 复位超时:- 电压 - 阀值:1.8V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:6-TSOP（0.059"，1.50mm 宽）5 引线 供应商设备封装:5-TSOP 包装:剪切带 (CT) 其它名称:NCP301HSN18T1GOSCT |
| LTC690CN8#PBF | 功能描述:IC MPU SUPERVISORY CIRCUIT 8-DIP RoHS:是 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 其它有关文件:STM6905 View All Specifications 标准包装:1 系列:- 类型:多压监控器 监视电压数目:5 输出:开路漏极或开路集电极 复位:低有效 复位超时:最小为 140 ms 电压 - 阀值:2.188V，2.955V，可调，可调，可调 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 供应商设备封装:8-TSSOP 包装:Digi-Reel® 产品目录页面:1197 (CN2011-ZH PDF) 其它名称:497-8728-6 |
| LTC690CN8PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Microprocessor Supervisory Circuits |
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