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 ADM690AARN are functionally comparable microprocessor supervisory circuits from the same manufacturer family, sharing core voltage-monitoring and reset-generation capabilities. While the ADM691ARZ offers additional watchdog and manual-reset functionality in a wider SOIC package, the ADM690AARN provides a compact TSSOP option for space-constrained designs. Designers should validate the specific feature set and package footprint requirements before substituting one for the other in a given application.
Function Type
High match
Package Type
Validation required
Reset Threshold
Validation required
Watchdog Timer
Not compatible
Parts at a glance
Part B
ADM690AARN
ADI公司
- Lifecycle
- Active
- Stock
- 2172 件
- Series
- 電源管理（PMIC）-首長
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 | ADM690AARN | Why it matters |
|---|---|---|---|
| Package / Mounting Type | 16-Lead SOIC (Surface Mount) | 8-Lead SOIC (Surface Mount) | Different package and pin count affect PCB footprint and layout; they are not drop-in replacements for each other. |
| Number of Supervised Supplies | Dual (main VCC plus secondary supply monitoring) | Single (VCC only) | The ADM691ARZ can monitor two supplies, while the ADM690AARN monitors only one; this changes system applicability. |
| Reset Threshold Voltage | 4.65 V (standard reset threshold option) | 4.65 V | Reset threshold determines the supply voltage at which a reset is asserted; matching thresholds is critical for reliable brownout detection. |
| Watchdog Timer | Yes (integrated watchdog) | Yes (integrated watchdog) | Watchdog supervision resets the processor if it stops responding; both include it, but pinout differences still prevent direct substitution. |
| Manual Reset Input | Yes | Yes | A manual reset input allows external system reset; both provide it, supporting similar reset control behavior. |
| Backup Battery Switchover | Yes (battery backup switchover) | No | Battery switchover maintains memory/real-time clock power during main supply loss; the ADM690AARN lacks this feature, limiting functional equivalence. |
| Supply Voltage Range (VCC) | 4.75 V to 5.5 V (5 V operation) | 4.75 V to 5.5 V (5 V operation) | Operating supply range must match the system rail; both target 5 V systems, so supply compatibility is similar. |
| Reset Output Type | Active Low RESET and Active High RESET outputs | Active Low RESET output | Output polarity options determine compatibility with the processor reset pin; the ADM691ARZ offers both polarities while the ADM690AARN offers only active low. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Industrial temperature range ensures operation across harsh environments; both meet the same range. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADM691ARZ | ADM690AARN |
|---|---|---|
| Part Status | Active | Obsolete |
| Digi Key Programmable | - | Not Verified |
| 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 | 140ms Minimum |
| Operating Temperature | -40°C ~ 85°C (TA) | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Base Product Number | - | ADM690 |
Frequently asked questions
What are the primary differences between the ADM691ARZ and the ADM690AARN?
The ADM691ARZ is a microprocessor supervisory circuit in a 16-lead SOIC package that includes a watchdog timer, a manual reset input, and a 1.3 V threshold line monitor comparator. The ADM690AARN is a similar supervisory circuit in an 8-lead SOIC package that provides power-fail warning and reset functions but does not include the watchdog timer or the additional line monitor comparator. The ADM691ARZ offers more integrated monitoring features, while the ADM690AARN provides a smaller footprint with basic reset and power-fail detection.
Are the ADM691ARZ and ADM690AARN pin-to-pin compatible?
No. The ADM691ARZ is housed in a 16-lead SOIC package, while the ADM690AARN is housed in an 8-lead SOIC package. The pin counts and pin functions differ, so they cannot be used interchangeably on the same PCB land pattern without redesign.
What supply voltage range do the ADM691ARZ and ADM690AARN support?
Both devices are specified for operation from a +5 V supply and are designed for 5 V microprocessor systems. The reset threshold voltage for both parts is typically 4.65 V, which is suitable for monitoring a 5 V logic supply with a 5% tolerance.
Does the ADM691ARZ include a watchdog timer while the ADM690AARN does not?
Yes. The ADM691ARZ integrates a watchdog timer that monitors microprocessor activity and asserts a reset if the processor fails to toggle the watchdog input within the timeout period. The ADM690AARN does not include a watchdog timer; it provides reset and power-fail warning functions only.
What is the difference in reset output configuration between the two parts?
Both the ADM691ARZ and ADM690AARN provide an active-low reset output. The ADM691ARZ additionally provides an active-high reset output, giving designers flexibility for different processor reset input polarities. The ADM690AARN provides only the active-low reset output.
Can the ADM690AARN be used as a drop-in replacement for the ADM691ARZ in an existing design?
No. Because the ADM690AARN has fewer pins, a different package, and lacks the watchdog timer and active-high reset output, it cannot be a drop-in replacement for the ADM691ARZ. Any substitution requires a PCB redesign and verification that the reduced feature set meets the system requirements.
What are the operating temperature ranges for the ADM691ARZ and ADM690AARN?
Both devices are specified for the industrial temperature range of −40 °C to +85 °C, making them suitable for use in industrial and embedded control applications.