feature

Specified overtemperature; low power consumption (12 μA); accurate monitoring of 2.5 V, 3 V, 3.3 V, and 5 V supply voltages; reset timeout 140 ms (min); manual reset input; output stage; push-pull reset output ( ADM6711 ); open-drain reset output (ADM6713); reset assertion to 1 V VCC power-fail immunity; 4-lead SC70 package.

application

Microprocessor systems; computers; controllers; intelligent instrumentation automotive systems.

General Instructions

The ADM6711/ADM6713 are reset generator circuits for microprocessor-based systems. They provide reset signals on power-up, power-down, and supply voltages below preset thresholds. In addition, both parts have de-noised manual reset inputs so that the reset signal can also be activated with an external switch or logic signal.

The ADM6711/ADM6713 have six different reset threshold options ranging from 2.32 V to 4.63 V for monitoring 2.5 V, 3 V, 3.3 V, and 5 V supplies. A reset timeout of at least 140 ms occurs when V rises above the threshold. This allows time for the supply voltage to stabilize before the microprocessor starts up.

The ADM6711 has push-pull outputs, so no additional external components are required. The ADM6713 open-drain output requires an external pull-up resistor, which can be connected to a voltage higher than V if desired.

These parts feature high reliability, an accurate voltage reference, and immunity to fast, negative-going transients on V. The low current consumption and space-efficient, 4-lead SC70 package make the ADM6711/ADM6713 ideal for low-power portable applications.

Typical performance characteristics

Circuit Description

The ADM6711/ADM6713 are designed to protect the integrity of system operation by ensuring proper system operation during power-on, power-off, and power-off states.

When the ADM6711/ADM6713 are powered up, the reset output remains low for a period equal to the typical reset activity timeout period. This is to give the system time to power up properly and allow the power to stabilize before any device comes out of reset and is allowed to start executing instructions. Initializing the system in this manner provides a more reliable startup for the microprocessor system.

Manual reset input

The ADM6711/ADM6713 manual reset (MR) input allows the system operator to reset the system via an external manual switch. Alternatively, a logic signal from another digital circuit can be used to trigger a reset via the MR input.

The MR input ignores negative-going pulses greater than 100ns (typical) and is guaranteed to accept any negative-going input with a duration greater than or equal to 1µs. RESET When MR is held low for 240ms, the output is held low (typical) after MR returns high.

If the MR is connected to long cables or used in a noisy environment, then placing a 0.1µF capacitor between the MR input and ground helps to eliminate any fast negative transients.

Power Failure Immunity

The ADM6711/ADM6713 contain internal filtering circuitry that provides immunity to fast transient faults on the power supply line. Figure 9 illustrates fault immunity performance by showing the maximum transient duration without reset pulses causing faults with amplitudes ranging from 1 mV to 1000 mV.

Fault immunity makes the ADM6711/ADM6713 suitable for use in noisy environments. Installing a 0.1µF decoupling capacitor as close as possible to the V pin further improves fault immunity.

ADM6713 reset output logic level

The ADM6713 open-drain reset output is designed for use with external pull-up resistors. This resistor can be used with V or any other reasonable voltage level, providing the flexibility to drive a variety of different logic level circuits using the ADM6713.

Ensure a valid reset output drops to V=0V

When V drops below 0.8 V, the reset output of the ADM6711/ADM6713 no longer sinks current, and the high-impedance CMOS logic input connected to reset may drift to an indeterminate logic level. To eliminate this problem, a pull-down resistor is connected from reset to ground. The 100 kΩ resistor is large enough not to load reset and small enough to pull reset to ground.

Dimensions