KA556I Equivalent & Substitute Parts Reference

Part Overview

The KA556I is a dual timer/oscillator IC manufactured by onsemi, utilizing 555-type circuitry in a 14-DIP package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The 555-type timer architecture remains a foundational building block in timing and oscillation applications, with multiple manufacturers offering compatible alternatives across different performance tiers and compliance levels.

Substiute Parts

KA556I

onsemiIn Stock: 815KA556I Datasheet

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NA556N

Texas InstrumentsIn Stock: 1357NA556N Datasheet

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NE556N

STMicroelectronicsIn Stock: 30933NE556N Datasheet

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SA556N

STMicroelectronicsIn Stock: 2927SA556N Datasheet

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TLC556CN

Texas InstrumentsIn Stock: 2151TLC556CN Datasheet

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TLC556IN

Texas InstrumentsIn Stock: 2159TLC556IN Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the KA556I is determined by strict adherence to the following electrical and mechanical parameters:

Critical Compatibility Parameters:

• Package type: 14-DIP (0.300", 7.62mm) with Through Hole mounting
• Supply voltage range: Must encompass or be compatible with 4.5V ~ 16V
• Functional type: 555-type dual timer/oscillator IC
• Pin configuration: 14-pin DIP

Acceptable Variation Parameters:

• Supply current: Substitute parts may exceed the 16 mA specification of the KA556I, provided the application circuit design accommodates higher current draw
• Operating temperature range: Substitute parts with extended or different temperature ranges are acceptable if the application operates within the substitute part's specified range
• Product status: Active or Last Time Buy parts are preferred over obsolete alternatives for new designs

Non-Substitutable Parameters:

• Package type and pin count
• Basic 555-type functional architecture
• DIP package form factor

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute (Direct Replacement): NA556N (Texas Instruments) is the recommended primary substitute for KA556I. This part maintains identical supply voltage range (4.5V ~ 16V), identical package configuration (14-DIP), and is currently in Active product status. The NA556N operates at -40°C ~ 105°C, providing extended temperature coverage compared to the KA556I. Supply current increases from 16 mA to 20 mA, a 25% increase that must be evaluated within the application circuit design. ROHS3 compliance provides regulatory advantage for new designs.

Secondary Substitutes (Functional Equivalents): SA556N (STMicroelectronics) and NE556N (STMicroelectronics) are functionally equivalent alternatives with identical electrical parameters (4.5V ~ 16V supply, 20 mA current, 500kHz frequency specification). Both are classified as obsolete. SA556N provides the widest operating temperature range (-40°C ~ 105°C) among STMicroelectronics offerings. NE556N operates at 0°C ~ 70°C, limiting applicability to commercial temperature range applications.

Low-Power Alternatives (Performance Enhancement): TLC556IN (Texas Instruments, Active status) and TLC556CN (Texas Instruments, Last Time Buy status) represent LinCMOS™ technology variants with significantly reduced supply current (720 µA versus 16-20 mA). These parts operate at higher maximum frequency (2.1MHz) and require modified supply voltage consideration: TLC556IN operates at 3V ~ 15V, while TLC556CN operates at 2V ~ 15V. These alternatives are suitable for power-constrained applications where the lower current draw justifies circuit redesign for the modified voltage range.

Compliance Considerations: All substitute parts listed maintain REACH Unaffected status and EAR99 ECCN classification, matching the regulatory profile of the KA556I. ROHS3 compliance is available across all active and last-time-buy alternatives, supporting modern manufacturing and environmental requirements.

Frequently Asked Questions (FAQ)

Q: Can NA556N directly replace KA556I without circuit modification? A: NA556N is pin-compatible and functionally equivalent within the 4.5V ~ 16V supply range. The 4 mA increase in supply current (16 mA to 20 mA) must be evaluated in the application circuit. If the power supply and current-limiting components are designed with adequate margin, direct substitution is feasible. If the circuit operates at the upper current limit of the original design, power supply recalculation is required.

Q: What is the difference between NE556N and SA556N? A: Both parts are STMicroelectronics 555-type dual timers with identical electrical specifications (4.5V ~ 16V, 20 mA, 500kHz frequency). The primary difference is operating temperature range: SA556N covers -40°C ~ 105°C, while NE556N covers 0°C ~ 70°C. For applications requiring extended low-temperature operation below 0°C, SA556N is the appropriate selection.

Q: Why would I choose TLC556IN over NA556N? A: TLC556IN is selected for power-sensitive applications where the 720 µA supply current (versus 20 mA for NA556N) provides significant power savings. TLC556IN operates at higher frequency (2.1MHz) and requires supply voltage in the 3V ~ 15V range. Circuit redesign is necessary to accommodate the modified voltage specification. TLC556IN is appropriate for battery-powered or low-power applications where the design effort justifies the power reduction.

Q: Are all substitute parts available in the same packaging? A: All listed substitute parts are available in 14-DIP (0.300", 7.62mm) Through Hole packages, maintaining mechanical compatibility with KA556I PCB layouts. Supplier device packages vary (14-MDIP, 14-PDIP, 14-DIP), but these represent manufacturer-specific designations for the same physical 14-DIP form factor.

Q: What is the product status significance for component selection? A: Product status indicates manufacturing availability and long-term support. Active status (NA556N, TLC556IN) indicates ongoing production and indefinite availability. Last Time Buy status (TLC556CN) indicates limited production window before discontinuation. Obsolete status (KA556I, NE556N, SA556N) indicates no further production; existing inventory only. For new designs, Active status parts are preferred. For legacy system support, Last Time Buy or Obsolete parts may be necessary if inventory is available.

Q: Can I use TLC556CN instead of TLC556IN? A: Both parts are LinCMOS™ technology with identical electrical specifications (2.1MHz, 720 µA, 14-DIP package). TLC556CN is Last Time Buy status with limited availability, while TLC556IN is Active status with ongoing production. For new designs, TLC556IN is the appropriate selection. TLC556CN may be used if existing inventory is available and the application does not require extended low-temperature operation (TLC556CN operates 0°C ~ 70°C versus TLC556IN at -40°C ~ 85°C).