CAT9554AWI-GT2 Equivalent & Substitute Parts

Part Overview

The CAT9554AWI-GT2 is an 8-channel I/O expander interface circuit manufactured by onsemi, designed for I2C and SMBus communication at 400 kHz. The device features push-pull output configuration with interrupt output capability and power-on reset (POR) functionality. The part is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain functional compatibility across I/O count, interface protocol, clock frequency, and electrical characteristics while accommodating different package options and supply voltage ranges.

Key Parameters

Parameter	CAT9554AWI-GT2
Number of I/O	8
Interface Protocol	I2C, SMBus
Clock Frequency	400 kHz
Output Type	Push-Pull
Interrupt Output	Yes
Current - Output Source/Sink	10mA, 24mA
Voltage - Supply	2.3V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package / Case	16-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the CAT9554AWI-GT2 are selected based on the following critical parameters that determine functional compatibility:

Core Compatibility Criteria:

Number of I/O: Must be 8 channels
Interface Protocol: Must support I2C (SMBus support is optional but preferred)
Clock Frequency: Must operate at 400 kHz
Output Type: Must be push-pull configuration
Interrupt Output: Must be present
Mounting Type: Must be surface mount

Acceptable Variations:

Package / Case: Different package options are acceptable (16-SOIC, 16-TSSOP, 16-SSOP, 24-QSOP, 24-TQFN, 16-VQFN) provided PCB layout accommodates the physical dimensions
Voltage - Supply: Substitute parts may have wider or narrower supply voltage ranges; designs must operate within the overlap range
Operating Temperature: Substitute parts may have extended temperature ranges; minimum requirement is -40°C ~ 85°C coverage
Current - Output Source/Sink: Substitute parts may have equal or higher current ratings; lower ratings are not acceptable
Product Status: Active or Last Time Buy status is preferred over obsolete

Substitute parts are grouped by package type to facilitate PCB layout considerations and assembly process compatibility.

Parameter Comparison

Part Number	Manufacturer	I/O Count	Interface	Clock Freq	Output Type	Interrupt	Supply Voltage	Temp Range	Package	Status
CAT9554AWI-GT2	onsemi	8	I2C, SMBus	400 kHz	Push-Pull	Yes	2.3V ~ 5.5V	-40°C ~ 85°C	16-SOIC	Obsolete
PCA9554ADWR	Texas Instruments	8	I2C, SMBus	400 kHz	Push-Pull	Yes	2.3V ~ 5.5V	-40°C ~ 85°C	16-SOIC	Last Time Buy
TCA9534ADWT	Texas Instruments	8	I2C	400 kHz	Push-Pull	Yes	1.65V ~ 5.5V	-40°C ~ 85°C	16-SOIC	Active
TCA9534DWR	Texas Instruments	8	I2C	400 kHz	Push-Pull	Yes	1.65V ~ 5.5V	-40°C ~ 85°C	16-SOIC	Active
TCA6408APWR	Texas Instruments	8	I2C, SMBus	400 kHz	Push-Pull	Yes	1.65V ~ 5.5V	-40°C ~ 85°C	16-TSSOP	Active
TCA6408ARGTR	Texas Instruments	8	I2C, SMBus	400 kHz	Push-Pull	Yes	1.65V ~ 5.5V	-40°C ~ 85°C	16-VQFN	Active
TCA9534PWR	Texas Instruments	8	I2C	400 kHz	Push-Pull	Yes	1.65V ~ 5.5V	-40°C ~ 85°C	16-TSSOP	Active
TCA9538DBR	Texas Instruments	8	I2C	400 kHz	Push-Pull	Yes	1.65V ~ 5.5V	-40°C ~ 85°C	16-SSOP	Active
MAX7324AEG+T	Analog Devices Inc./Maxim Integrated	8	I2C	400 kHz	Push-Pull	Yes	1.71V ~ 5.5V	-40°C ~ 125°C	24-QSOP	Active
MAX7324ATG+T	Analog Devices Inc./Maxim Integrated	8	I2C	400 kHz	Push-Pull	Yes	1.71V ~ 5.5V	-40°C ~ 125°C	24-TQFN	Active
MAX7324ATG+	Analog Devices Inc./Maxim Integrated	8	I2C	400 kHz	Push-Pull	Yes	1.71V ~ 5.5V	-40°C ~ 125°C	24-TQFN	Active

Engineering Selection Recommendations

For Direct Package Replacement (16-SOIC): PCA9554ADWR is the primary substitute, maintaining identical package, supply voltage range, and operating temperature specifications. Product status is Last Time Buy, indicating limited availability. TCA9534ADWT and TCA9534DWR offer active product status with compatible 16-SOIC packaging but operate at lower minimum supply voltage (1.65V vs 2.3V), requiring design verification that supply rails remain within 1.65V ~ 5.5V overlap range.

For Alternative Package Options: TCA6408APWR and TCA9534PWR provide 16-TSSOP packaging with active product status and SMBus support (TCA6408APWR). TCA6408ARGTR offers 16-VQFN packaging with SMBus support and active status. TCA9538DBR provides 16-SSOP packaging with active status. All alternatives operate at 1.65V ~ 5.5V supply voltage range.

For Extended Temperature Range: MAX7324 series parts (MAX7324AEG+T, MAX7324ATG+T, MAX7324ATG+) provide -40°C ~ 125°C operating range with active product status. These parts require different package accommodations (24-QSOP or 24-TQFN) and operate at 1.71V ~ 5.5V supply voltage.

Compliance Considerations: All substitute parts carry RoHS3 compliance and REACH Unaffected status, matching the regulatory requirements of the original part. Moisture sensitivity levels range from MSL 1 (Unlimited) to MSL 2 (1 Year), requiring appropriate handling procedures during storage and assembly.

Frequently Asked Questions (FAQ)

Q: Can I use TCA9534ADWT as a direct replacement for CAT9554AWI-GT2? A: TCA9534ADWT is functionally compatible in 16-SOIC package with matching I/O count, interface, clock frequency, and operating temperature range. The primary difference is supply voltage range: TCA9534ADWT operates at 1.65V ~ 5.5V versus CAT9554AWI-GT2 at 2.3V ~ 5.5V. Substitution is valid if your design operates within the 2.3V ~ 5.5V overlap range. TCA9534ADWT lacks SMBus support, supporting I2C only.

Q: What is the difference between PCA9554ADWR and TCA9534DWR? A: Both are 16-SOIC I2C/I2C+SMBus I/O expanders with 8 channels and 400 kHz operation. PCA9554ADWR maintains the original 2.3V ~ 5.5V supply voltage range and includes SMBus support. TCA9534DWR operates at 1.65V ~ 5.5V with I2C only. PCA9554ADWR is Last Time Buy status; TCA9534DWR is active. Select based on supply voltage requirements and SMBus protocol necessity.

Q: Why do MAX7324 parts have different package options? A: MAX7324 series offers multiple package variants (24-QSOP, 24-TQFN) to accommodate different PCB layout requirements and assembly processes. All variants maintain identical electrical specifications: 8 I/O, I2C 400 kHz, push-pull output, interrupt capability, and extended -40°C ~ 125°C temperature range. Package selection depends on available PCB footprint space and manufacturing equipment compatibility.

Q: Are all substitute parts RoHS compliant? A: All listed substitute parts carry RoHS3 compliance status. The original CAT9554AWI-GT2 does not specify RoHS status in provided data. Verify RoHS compliance requirements for your application before final part selection.

Q: What is the impact of different current ratings on substitution? A: CAT9554AWI-GT2 specifies 10mA source and 24mA sink current. Substitute parts with equal or higher ratings (e.g., TCA6408APWR at 10mA/25mA) are acceptable. Parts with unspecified current ratings require datasheet verification before use in current-sensitive applications.

Q: Can I use a 24-pin package substitute in place of the 16-pin original? A: No. Package pin count and footprint differences require PCB redesign. MAX7324 series (24-pin packages) cannot be used as drop-in replacements without circuit board modification. Select substitutes matching your current PCB package requirement or plan for board redesign.

Q: What is the significance of product status (Active vs. Last Time Buy vs. Obsolete)? A: Active status indicates ongoing production and long-term availability. Last Time Buy indicates limited production window before discontinuation. Obsolete indicates no further production. For new designs, select Active status parts. For legacy system support, Last Time Buy parts provide transition options before full obsolescence.

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