参数资料
型号: MAX7391AMTP
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: 时钟产生/分配
英文描述: 8 MHz, OTHER CLOCK GENERATOR, PDSO8
封装: MO-187C-AA, MICRO, SOP-8
文件页数: 9/12页
文件大小: 594K
代理商: MAX7391AMTP
Detailed Description
The MAX7391 replaces ceramic resonators, crystals,
and supervisory functions for microcontrollers in 3.3V
and 5V applications.
The MAX7391 provides a clock source, reset, and
power-fail functions. The power-fail output provides
early warning of power failure. The power-fail threshold
is configurable to detect either an external voltage or
the VCC supply voltage to the device.
The clock output can be switched between normal and
half-speed operation. This functionality allows the
microcontroller to operate at reduced power and may
be used to extend the time available to perform house-
keeping tasks, such as writing data to flash, during a
power failure. Connecting the power-fail output (PFO)
to the SPEED input reduces clock speed automatically
during power-fail events.
The integrated reset provides the power-supply monitor-
ing functions necessary to ensure correct microcontroller
operation. The reset circuit has built-in power-supply
transient immunity and provides both power-on reset
and power-fail or brownout reset functionality. Two stan-
dard factory-trimmed reset levels are available.
A power-fail function is provided for power-supply volt-
age monitoring and can provide advance notice of an
impending power failure. The power-fail input monitors
external power-supply voltages through an external
resistive divider. Connect PFI to VCC to monitor VCC.
Clock Output (CLOCK)
The push-pull clock output (CLOCK) drives a ground-
connected 1k
load or a positive supply connected
500
load to within 300mV of either supply rail. CLOCK
remains stable over the full operating voltage range and
does not generate short output cycles during either
power-on or power-off. A typical startup characteristic is
shown in the Typical Operating Characteristics section.
The clock output frequency is reduced by a factor of
two by taking SPEED low. This functionality allows the
microcontroller to operate at reduced power and may
be used to extend the time available to perform house-
keeping tasks, such as writing data to flash during
power failure.
Reset
The reset function drives the microcontroller reset input
to prevent operation in the cases of the initial power-on
setting, low power-supply voltages, and the failed
watchdog operations. Three reset output versions are
available: push-pull RST, push-pull RST, and open-drain
RST. The reset timeout period (tRST) is nominally 135s.
Power-On Reset (POR)
The internal power-on reset (POR) circuit detects the
power-supply voltage (VCC) level at startup. The POR
circuit starts the oscillator when VCC exceeds the reset
rising threshold level (VTH+). The reset output remains
asserted from the time VCC crosses the VTH+ and con-
tinues to be asserted for the reset timeout period (tRST).
Upon completion of the reset timeout, the reset output
is released. See Figure 1.
MAX7391
Speed-Switching Clock Generator
with Power Fail
6
_______________________________________________________________________________________
PIN
NAME
FUNCTION
1
PFI
Power-Fail Input. PFI monitors the condition of either an external supplied voltage or VCC. See the Power Fail
section for more details.
2VCC
Power Input. Connect VCC to the power supply. Bypass VCC to GND with a 0.1F capacitor. Install the
bypass capacitor as close to the device as possible.
3
N.C.
No Connection
4
GND
Ground
5
PFO
Power-Fail Output. Open-drain output asserts when the voltage being monitored drops below the power-fail
threshold voltage.
6
SPEED
Clock-Speed Select Input. Connect SPEED high for the factory-trimmed clock output frequency. Connect
SPEED low to reduce the clock output frequency by half.
7
RST/RST
Reset Output. Reset output is available in one of three configurations: push-pull RST, push-pull RST,
or open-drain RST. The reset output occurs if any combination of the following conditions occurs: reset
output is asserted during power-up, and whenever VCC is below the reset threshold level; for devices with WDI,
reset output asserts when WDI does not receive a rising or falling edge within the watchdog timeout period.
8
CLOCK
Clock Output
Pin Description
相关PDF资料
PDF描述
MAX7391BQVB 12 MHz, OTHER CLOCK GENERATOR, PDSO8
MAX7391CJWB 16 MHz, OTHER CLOCK GENERATOR, PDSO8
MC9S12GC16MPBE25 16-BIT, FLASH, 25 MHz, MICROCONTROLLER, PQFP52
MPC8548EHXATG 32-BIT, 1200 MHz, MICROPROCESSOR, CBGA783
MPC8548EVUATGA 32-BIT, 1200 MHz, MICROPROCESSOR, CBGA783
相关代理商/技术参数
参数描述
MAX7391CMAC 功能描述:时钟发生器及支持产品 RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56
MAX7391CMRD 功能描述:时钟发生器及支持产品 RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56
MAX7391CMRD-T 制造商:Maxim Integrated Products 功能描述:SPEED-SWITCHING CLOCK GENERATOR WIT - Tape and Reel
MAX7391CMTP 功能描述:时钟发生器及支持产品 RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56
MAX7391CMTP-T 功能描述:时钟发生器及支持产品 RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56