参数资料
型号: XR17D154CV-0A-EVB
厂商: Exar Corporation
文件页数: 16/69页
文件大小: 0K
描述: EVAL BOARD FOR XR17D154 144TQFP
标准包装: 1
系列: *
xr
XR17D154
REV. 1.2.2
UNIVERSAL (3.3V AND 5V) PCI BUS QUAD UART
23
3.0 CRYSTAL OSCILLATOR / BUFFER
The D154 includes an on-chip oscillator (XTAL1 and XTAL2). The crystal oscillator provides the system clock
to the Baud Rate Generators (BRG) in each of the 4 UARTs, the 16-bit general purpose timer/counter and
internal logics. XTAL1 is the input to the oscillator or external clock buffer input with XTAL2 pin being the
output. Caution: The XTAL1 input is not 5V tolerant. See Programmable Baud Rate Generator in the UART
section for programming details.
The on-chip oscillator is designed to use an industry standard microprocessor crystal (parallel resonant with
10-22 pF capacitance load, 100ppm) connected externally between the XTAL1 and XTAL2 pins (see Figure 9).
Alternatively, an external clock can be connected to the XTAL1 pin to clock the internal 4 baud rate generators
for standard or custom rates. However, for external clock frequencies greater than 24MHz, a 2K pull-up may be
necessary on the XTAL2 output (see Figure 10). Typically, the oscillator connections are shown in Figure 9.
For further reading on oscillator circuit please see application note DAN108 on EXAR’s web site.
FIGURE 9. TYPICAL OSCILLATOR CONNECTIONS
FIGURE 10. EXTERNAL CLOCK CONNECTION FOR EXTENDED DATA RATE
C1
22-47pF
C2
22-47pF
14.7456
MHz
XTAL1
XTAL2
R=300K to 400K
2K
XTAL1
XTAL2
R1
VCC
External Clock
vcc
gnd
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XR17D154CV-F 功能描述:UART 接口集成电路 3.3V-5V 64B FIFO temp 0C to 70C; UART RoHS:否 制造商:Texas Instruments 通道数量:2 数据速率:3 Mbps 电源电压-最大:3.6 V 电源电压-最小:2.7 V 电源电流:20 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:LQFP-48 封装:Reel
XR17D154CVTR-F 制造商:Exar Corporation 功能描述:UART 4-CH 64Byte FIFO 3.3V/5V 144-Pin LQFP T/R 制造商:Exar Corporation 功能描述:XR17D154CVTR-F
XR17D154IV 功能描述:UART 接口集成电路 UART RoHS:否 制造商:Texas Instruments 通道数量:2 数据速率:3 Mbps 电源电压-最大:3.6 V 电源电压-最小:2.7 V 电源电流:20 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:LQFP-48 封装:Reel
XR17D154IV-F 功能描述:UART 接口集成电路 3.3V-5V 64B FIFO temp -45 to 85C;UART RoHS:否 制造商:Texas Instruments 通道数量:2 数据速率:3 Mbps 电源电压-最大:3.6 V 电源电压-最小:2.7 V 电源电流:20 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:LQFP-48 封装:Reel
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