了解直流电气特性的微控制器-Understanding DC

文章摘要：PARAMETERSYMBOLMINTYPMAXUNITSNOTESPower-Fail WarningVPFW4.254.384.55V1The DS80C320 incorporates a precision bandgap voltage reference to determine when VCC is out of tolerance. The bandgap reference provides a precise voltage to compare with VCC. If VCC should fall, the power monitor compares it to

了解直流电气特性的微控制器-Understanding DC,标签：计算机控制技术,工厂电气控制技术,http://www.88dzw.com

PARAMETER	SYMBOL	MIN	TYP	MAX	UNITS	NOTES
Power-Fail Warning	VPFW	4.25	4.38	4.55	V	1

The DS80C320 incorporates a precision bandgap voltage reference to determine when VCC is out of tolerance. The bandgap reference provides a precise voltage to compare with VCC. If VCC should fall, the power monitor compares it to the bandgap reference. Analog circuits internal to the microcontroller detect when VCC crossed the predetermined power-fail warning threshold. An optional early warning power-fail interrupt can be generated in the event of a low power-supply voltage. When VCC reaches VPFW threshold, the device generates a power-fail interrupt.

PARAMETER	SYMBOL	MIN	TYP	MAX	UNITS	NOTES
Minimum Operating Voltage	VRST	4.0	4.1	4.25	V	1, 12

The minimum operating voltage parameter describes the power-supply voltage range that invokes a power-fail reset. Prior to this condition, the power-supply voltage must pass through the power-fail warning minimum voltage. If the power-fail warning interrupt is not enabled and VCC crosses the threshold of minimum operating voltage, a power-fail reset occurs. Upon a power-fail reset, the device halts operations and places all the output pins to the reset state. When the VCC voltage is restored and exceeds VRST, the internal detection circuits activate the on-chip crystal oscillator and count 65,536 oscillator clocks. If VCC falls below the VRST threshold during this startup period, the process restarts.

PARAMETER	SYMBOL	MIN	TYP	MAX	UNITS	NOTES
Supply Current Active Mode at 25MHz	ICC		30	45	mA	2

If a milliampere meter were connected in series with the VCC pin, it would indicate the total device current draw, ICC. The supply current is a function of the operating frequency. Following the DC Characteristics table in the DS80C320 data sheet is an ICC versus frequency curve. Notice how ICC increases as frequency is increased. Also notice VCC is held constant. The values of ICC found in the data sheet is measured under a controlled condition. An external 25MHz clock source drives the XTAL1 pin of the microcontroller. The VCC and RST pins are connected to 5.5V. All other pins on the DS80C320 are disconnected.

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