MAX6700UT-T 查看數據表（PDF） - Maxim Integrated

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MAX6700UT-T

Low-Voltage, High-Accuracy, Triple/Quad Voltage µP Supervisory Circuits in SOT Package

Maxim Integrated 

Low-Voltage, High-Accuracy, Triple/Quad

Voltage µP Supervisory Circuits in SOT Package

IN_

VTH_

VTH_

RESET

10%

tRD

90%

tRP

Figure 3. RESET Output Timing Diagram

IN2 = +3.3V

IN2

RESET

+5V

100kΩ

VCC

RESET

MAX6700

MAX6710

GND

GND

Figure 4. Interfacing to Different Logic-Supply Voltage

VINTH

R1

R2

VREF = 0.62V

( ) R1 = R2

VINTH

0.62V

-

1

Figure 5. Setting the Auxiliary Monitor

VCC powers the MAX6700/MAX6710Q and is not a

monitored voltage. IN2 powers all other options for the

MAX6710 and is a monitored voltage. When any supply

drops below its threshold, the reset output asserts low

and remains low while either IN1 or IN2 is above 1.0V.

Adjustable Thresholds

The MAX6700/MAX6710 offer several monitor options

with adjustable reset thresholds. The threshold voltage at

each adjustable IN_ input is typically 0.62V. To monitor a

voltage > 0.62V, connect a resistor-divider network to the

circuit as shown in Figure 5.

VINTH = 0.62V x (R1 + R2) / R2

or, solved in terms of R1:

R1 = R2 ((VINTH / 0.62V) - 1)

Because the MAX6700/MAX6710 have a guaranteed

input current of ±0.2µA (±0.4µA for IN1) on their

adjustable inputs, resistor values up to 100kΩ can be

used for R2 with < 1% error. The MAX6700/MAX6710Q

include an internal voltage clamp (1.5V typ) at each of

the adjustable voltage inputs. An input voltage higher

than 1.5V induces a higher input current.

Unused Inputs

Connect unused monitor inputs to a supply voltage

greater in magnitude than their specified threshold volt-

ages. For unused IN_ adjustable inputs, connect a 1MΩ

series resistor between the unused input and IN2 (or

VCC) to limit the bias current. Use IN2 for normal opera-

tion (device power-supply pin). Do not connect unused

monitor inputs to ground or allow them to float.

Adding Manual Reset Capability

(MAX6710)

Figure 6 shows an application circuit adding manual reset

to the MAX6710. Depressing the pushbutton switch short-

circuits the analog input to ground and initiates a RESET

pulse. The switch must be open for at least 140ms in

order to deassert the RESET output. No external switch

debounce is required. Use a small capacitor to improve

noise immunity when using long leads from the pushbut-

ton switch to the adjustable input.

Power-Supply Bypassing and Grounding

The MAX6700/MAX6710 are normally powered from the

monitored IN2 or from the VCC supply input. All monitored

inputs are immune to short supply transients. For higher

immunity in noisy applications, connect a 0.1µF bypass

capacitor from the IN2 input to ground. Add capacitance

to IN1, IN3, and IN4 to increase their noise immunity.

_______________________________________________________________________________________ 7

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