Part A
ADM691ARZ
ADI公司
- Lifecycle
- Active
- Stock
- 4235 件
- Package
- SOIC-16
- Series
- PMIC-首長
Replacement verdict
Compatible functional replacement candidate
The ADM691ARZ and ADM690ARM are both microprocessor supervisory circuits from Analog Devices with closely aligned core functions, making them a viable functional replacement candidate in many designs. However, the ADM691ARZ offers an adjustable reset threshold and a watchdog timer input, while the ADM690ARM provides a fixed reset threshold without a watchdog function, so engineers should validate reset timing, threshold accuracy, and watchdog requirements against the target application before substituting one for the other.
Function Type
High match
Reset Threshold
Validation required
Watchdog Timer
Validation required
Package Type
High match
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADM691ARZ | ADM690ARM | Why it matters |
|---|---|---|---|
| Reset Threshold Voltage (typ) | 4.65 V | 4.65 V | Determines the supply voltage level at which a reset is asserted; both share the same threshold, so reset behavior is equivalent. |
| Package / Mounting | 16-SOIC (surface mount) | 8-MSOP (surface mount) | Different footprints and pin counts affect PCB layout and are not drop-in compatible without redesign. |
| Number of Pins | 16 | 8 | Pin count dictates available functions and board routing; the two parts are not pin-compatible. |
| Watchdog Timer | Yes (with adjustable timeout) | Yes | Watchdog supervision resets the processor if it hangs; both provide it, but the ADM691ARZ offers adjustable timeout configuration. |
| Manual Reset Input | Yes | Yes | Allows external push-button or logic reset; both support it, preserving manual reset functionality. |
| Backup Battery Switchover | Yes | Yes | Enables battery backup during main supply loss; both include switchover, so backup behavior is comparable. |
| Reset Output Type | Active low and active high | Active low | Output polarity must match the processor reset input; the ADM691ARZ offers both polarities while the ADM690ARM provides only active-low. |
| Supply Voltage Range | 4.75 V to 5.5 V | 4.75 V to 5.5 V | Defines the operating supply window; identical ranges mean both suit standard 5 V systems. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Determines environmental suitability; identical ranges mean equivalent thermal tolerance. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADM691ARZ | ADM690ARM |
|---|---|---|
| Part Status | Active | Obsolete |
| Type | Battery Backup Circuit | Battery Backup Circuit |
| Number of Voltages Monitored | 1 | 1 |
| Voltage - Threshold | 4.65V | 4.65V |
| Output | Open Drain, Push-Pull | Push-Pull, Totem Pole |
| Reset | Active High/Active Low | Active Low |
| Reset Timeout | 35ms Minimum | 35ms Minimum |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the primary differences between the ADM691ARZ and ADM690ARM?
The ADM691ARZ is a microprocessor supervisory circuit in a 16-lead SOIC package that includes a watchdog timer, manual reset input, and adjustable reset threshold, while the ADM690ARM is a similar supervisory circuit in an 8-lead MSOP package. The ADM690ARM provides power-fail warning and reset functions but does not include the watchdog timer or manual reset features found on the ADM691ARZ.
Are the ADM691ARZ and ADM690ARM pin-to-pin compatible?
No. The ADM691ARZ uses a 16-lead SOIC (R-16) package, while the ADM690ARM uses an 8-lead MSOP (RM-8) package. The pin counts, pin functions, and PCB land patterns differ, so they are not direct drop-in replacements for each other.
What supply voltage range do the ADM691ARZ and ADM690ARM support?
Both devices are designed for 5 V microprocessor systems and operate from a supply voltage of 4.75 V to 5.5 V, with reset thresholds suitable for monitoring 5 V logic supplies. Designers should confirm the exact threshold option against the specific orderable part number in the manufacturer datasheet.
Does the ADM691ARZ include a watchdog timer while the ADM690ARM does not?
Yes. The ADM691ARZ integrates a watchdog timer that monitors microprocessor activity and asserts reset if the processor fails to toggle the watchdog input within the timeout period. The ADM690ARM does not include a watchdog timer; it provides reset and power-fail warning functions only.
Which device offers a manual reset input?
The ADM691ARZ provides a dedicated manual reset input that allows a pushbutton or logic signal to force a reset assertion. The ADM690ARM does not provide a manual reset input, so external circuitry would be required if manual reset capability is needed.
Can the ADM690ARM be used as a substitute for the ADM691ARZ in an existing design?
Not directly. Because the ADM690ARM lacks the watchdog timer and manual reset input and uses a different package and pinout, substituting it for the ADM691ARZ would require design changes, including PCB rework and verification that the missing functions are not needed. Any substitution should be validated against the manufacturer datasheets for both parts.
What are the package and mounting options for each device?
The ADM691ARZ is supplied in a 16-lead SOIC surface-mount package (R-16 suffix). The ADM690ARM is supplied in an 8-lead MSOP surface-mount package (RM-8 suffix). Both are surface-mount devices, but their footprints and thermal characteristics differ.