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| 型号： | LTC6991IS6#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/24页 |
| 文件大小： | 0K |
| 描述： | IC OSC SILICON 977HZ TSOT23-6 |
| 产品培训模块： | TimerBlox Family Timing Devices |
| 产品目录绘图： | LTC699_TSOT-23 |
| 特色产品： | TimerBlox? |
| 标准包装： | 2,500 |
| 系列： | TimerBlox® |
| 类型： | 振荡器 - 硅 |
| 频率： | 29.1µHz ~ 977Hz |
| 电源电压： | 2.25 V ~ 5.5 V |
| 电流 - 电源： | 135µA |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | SOT-23-6 细型，TSOT-23-6 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | TSOT-23-6 |
| 安装类型： | 表面贴装 |
| 配用： | DC1562A-B-ND - BOARD EVAL LTC6991 |
LTC6991
16
6991fb
Self-Resetting Circuits
The RST pin has hysteresis to accommodate slow-changing
input voltages. Furthermore, the trip points are proportional
to the supply voltage (see Note 6 and the RST Threshold
Voltage vs Supply Voltage curve in Typical Performance
Characteristics). This allows an RC time constant at the
RST input to generate a delay that is nearly independent
of the supply voltage.
A simple application of this technique allows the LTC6991
output to reset itself, producing a well-controlled pulse
once each cycle. Figures 13a and 13b show circuits that
produce approximately 1μs pulses once a minute. The
only difference is in the POL bit setting, which controls
whether the pulse is positive or negative.
Voltage Controlled Frequency
With one additional resistor, the LTC6991 output frequency
can be manipulated by an external voltage. As shown in
Figure 14, voltage VCTRL sources/sinks a current through
RVCO to vary the ISET current, which in turn modulates the
output frequency as described in Equation (3).
f
MHz
k
NR
R
V
OUT
DIV
VCO
SET
CTRL
S
=+
150
1024
1
Ω
E
ET
(3)
Digital Frequency Control
The control voltage can be generated by a DAC (digital-
to-analog converter), resulting in a digitally-controlled
frequency. Many DACs allow for the use of an external
reference. If such a DAC is used to provide the VCTRL
voltage, the VSET dependency can be eliminated by buffer-
ing VSET and using it as the DAC’s reference voltage, as
shown in Figure 15. The DAC’s output voltage now tracks
any VSET variation and eliminates it as an error source.
The SET pin cannot be tied directly to the reference input
of the DAC because the current drawn by the DAC’s REF
input would affect the frequency.
ISET Extremes (Master Oscillator Frequency Extremes)
When operating with ISET outside of the recommended
1.25μA to 20μA range, the master oscillator operates
outside of the 62.5kHz to 1MHz range in which it is most
accurate.
APPLICATIONS INFORMATION
LTC6991
2.25V TO 5.5V
0.1μF
OUT
R1
1M
R2
392k
RSET
715k
RST
GND
SET
OUT
V+
DIV
CPW
470pF
RPW
2.26k
6991 F13a
60 SECONDS
1μs PULSE WIDTH
VRST(RISING)
V+
tPULSE = –RPW CPW In
tPULSE ≈ –2.26kΩ 470pF In(1 – 0.61)
tPULSE ≈ 1μs
1–
LTC6991
2.25V TO 5.5V
0.1μF
6991 F13b
OUT
R1
392k
R2
1M
60 SECONDS
0.9μs PULSE WIDTH
VRST(FALLING)
V+
tPULSE = –RPW CPW In
tPULSE ≈ –2.26kΩ 470pF In(0.43)
tPULSE ≈ 0.9μs
RSET
715k
RST
GND
SET
OUT
V+
DIV
CPW
470pF
RPW
2.26k
6991 F14
LTC6991
RST
GND
SET
OUT
V+
DIV
R1
C1
0.1μF
R2
RSET
RVCO
VCTRL
V+
Figure 13a. Self-Resetting Circuit (DIVCODE = 4)
Figure 13b. Self-Resetting Circuit (DIVCODE = 11)
Figure 14. Voltage-Controlled Oscillator
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC6991MPS6#TRMPBF | 功能描述:IC OSCILLATOR RESET LF 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:TimerBlox® 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:45 系列:- 类型:温度 - 补偿晶体振荡器（TCXO） 计数:- 频率:25MHz 电源电压:3.135 V ~ 3.465 V 电流 - 电源:1.5mA 工作温度:-40°C ~ 85°C 封装/外壳:16-SOIC（0.295"，7.50mm 宽） 包装:管件 供应商设备封装:16-SOIC W 安装类型:表面贴装 |
| LTC6991MPS6#TRPBF | 功能描述:IC OSCILLATOR RESET LF 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:TimerBlox® 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:45 系列:- 类型:温度 - 补偿晶体振荡器（TCXO） 计数:- 频率:25MHz 电源电压:3.135 V ~ 3.465 V 电流 - 电源:1.5mA 工作温度:-40°C ~ 85°C 封装/外壳:16-SOIC（0.295"，7.50mm 宽） 包装:管件 供应商设备封装:16-SOIC W 安装类型:表面贴装 |
| LTC6992-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:TimerBlox Voltage-Controlled Pulse Width Modulator (PWM) |
| LTC6992-2 | 制造商:LINER 制造商全称:Linear Technology 功能描述:TimerBlox Voltage-Controlled Pulse Width Modulator (PWM) |
| LTC6992-3 | 制造商:LINER 制造商全称:Linear Technology 功能描述:TimerBlox Voltage-Controlled Pulse Width Modulator (PWM) |
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