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Microchip Technology 23A256T-I/ST
- Part No.:
- 23A256T-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
23A256T-I/ST.pdf
- Description:
- IC SRAM 256KBIT SPI 20MHZ 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,910
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Product details
Overview
23A256T-I/ST from Microchip Technology Inc. is a 256 Kbit (32,768 × 8-bit) low-voltage SPI Serial SRAM optimized for ultra-low-power embedded systems. It operates from 1.5 V to 1.95 V, supports up to 20 MHz clock frequency at 1.8 V, delivers 3 mA read current at 1 MHz, and draws only 4 µA max standby current at +85°C - enabling battery-backed data retention in portable medical sensors and industrial IoT edge nodes.
For engineers reviewing the 23A256T-I/ST datasheet, 23A256T-I/ST pinout, 23A256T-I/ST application, or 23A256T-I/ST equivalent, key selection criteria include its 1.5–1.95 V supply range, HOLD pin support for interrupt-safe SPI pausing, 32-byte page write capability, industrial temperature rating (−40°C to +85°C), and TSSOP-8 package compatibility with space-constrained PCB layouts.
Technical Context
The 23A256T-I/ST implements a true SPI-compatible serial interface with separate SI (data in) and SO (data out) lines, requiring only CS, SCK, SI, SO, HOLD, VCC, and VSS - no internal voltage regulation or command decoding logic beyond standard SPI framing. Its STATUS register controls three distinct operation modes: Byte (default), Page (32-byte auto-increment within page), and Sequential (full-array wraparound).
Timing is strictly synchronous to SCK rising edge for input sampling and falling edge for output update. The HOLD function suspends ongoing transfers without resetting internal address pointers, provided HOLD is asserted while SCK is low - ensuring deterministic resumption after host interrupt servicing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 32,768 × 8-bit (256 Kbit); supports byte/page/sequential access without external address latches |
| Supply voltage | 1.5 V to 1.95 V; enables direct integration with 1.8 V logic domains and eliminates level-shifting overhead |
| Max clock frequency | 20 MHz at VCC = 1.8 V; sustains 2.5 MB/s effective throughput in sequential read mode |
| Read current | 3 mA at 1 MHz, SO loaded; allows continuous background logging in energy-harvesting sensor nodes |
| Standby current | 4 µA max at +85°C; ensures >1-year data retention on coin-cell batteries (e.g., CR2032) |
| Page size | 32 bytes; minimizes write latency per page while limiting over-write risk during power loss |
| Data retention voltage | 1.2 V minimum; guarantees RAM content survival during brown-out events down to 1.2 V supply |
Pinout & Package
23A256T-I/ST is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, JEDEC MO-153 compliant, footprint compatible with SOIC-8 but 35% smaller area and lower profile.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select Input | Active-low enable; forces SO into high-impedance when deasserted, enabling multi-device SPI bus sharing |
| SO (Pin 2) | Serial Data Output | Tri-states automatically during HOLD or CS high; outputs data on SCK falling edge, MSB-first |
| VSS (Pin 4) | Ground Reference | Primary return path for all I/O and core logic; must be connected before VCC during power-up sequencing |
| SI (Pin 5) | Serial Data Input | Latches instruction/address/data on SCK rising edge; accepts standard SPI-level signals (VIL ≤ 0.2×VCC) |
| SCK (Pin 6) | Serial Clock Input | Edge-triggered master clock; rise/fall times ≤ 2 µs required for reliable timing margin at 20 MHz |
| HOLD (Pin 7) | Hold Input | Pauses active SPI transfer mid-sequence; requires STATUS register HOLD bit = 0 and SCK low to activate |
| VCC (Pin 8) | Supply Voltage | 1.5–1.95 V core supply; decoupling capacitor (0.1 µF X7R) required within 5 mm of pin for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage operation | 1.5–1.95 V supply enables direct coupling to 1.8 V microcontrollers (e.g., PIC24F, SAM D21) without regulators or LDOs |
| HOLD pin functionality | Enables deterministic pause/resume of SPI transfers during host interrupt handling - no retransmission or address reload needed |
| 32-byte page write | Reduces average write time by 31× vs. byte writes; limits data corruption window during unexpected power loss |
| Industrial temperature range | −40°C to +85°C operation validated across full voltage and timing specs - suitable for uncontrolled industrial enclosures |
| Pb-free & RoHS-compliant | TSSOP-8 package meets J-STD-020 moisture sensitivity level 3 (MSL3), supporting standard reflow profiles without baking |
Applications
| Medical Wearable Sensor Hub | Industrial PLC I/O Module |
|---|---|
Use Scenario: Continuous acquisition of ECG/accelerometer data in a battery-powered patch monitor with intermittent BLE transmission. IC Role / Device Role / Timing Role: SPI-connected nonvolatile scratchpad memory buffering raw sensor samples between wake cycles. Use Value: 4 µA standby current extends CR2032 battery life beyond 12 months; 1.8 V operation matches MCU I/O voltage, eliminating level shifters. | Use Scenario: Storing configuration parameters and transient process values in a DIN-rail mounted programmable logic controller with limited board space. IC Role / Device Role / Timing Role: External SRAM providing fast read/write access for ladder logic execution and real-time diagnostics. Use Value: TSSOP-8 footprint saves >40% PCB area vs. SOIC-8; −40°C to +85°C rating ensures reliability in factory-floor thermal cycling. |
| Smart Meter Data Logger | Automotive Body Control Unit |
Use Scenario: Capturing utility consumption snapshots every 15 minutes and retaining last 72 hours of data during mains power outage. IC Role / Device Role / Timing Role: Backup memory holding time-stamped kWh/kVAR readings accessible via SPI during brown-out conditions. Use Value: 1.2 V data retention threshold ensures integrity down to critical brown-out levels; 32-byte page writes minimize flash wear in hybrid storage architectures. | Use Scenario: Temporary storage of door lock status, seat position, and mirror calibration data in a 12 V automotive system with local 1.8 V LDO rail. IC Role / Device Role / Timing Role: Low-voltage SRAM interfacing directly with 1.8 V CAN microcontroller peripherals. Use Value: 1.5–1.95 V supply range aligns precisely with automotive-grade 1.8 V regulators; HOLD pin allows safe SPI suspension during CAN error interrupts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 23K256-I/ST | 3.0–3.6 V supply range; higher 10 mA read current at 20 MHz; same 32-byte page, HOLD, and TSSOP-8 package | Requires 3.3 V domain; unsuitable for 1.8 V-only systems; better noise immunity in electrically noisy environments | Select 23K256-I/ST only if existing 3.3 V rail is available and lower standby current is not critical |
| FM25V20-G | F-RAM technology; unlimited endurance (>10¹⁴ cycles); 2.0–3.6 V supply; 15 MHz max clock; SOIC-8 only | No write delays; eliminates page-write timing constraints; higher cost; no TSSOP option | Choose FM25V20-G when write-cycle endurance or zero write-time latency is mandatory, accepting larger footprint and higher BOM cost |
Compared with 23K256-I/ST, the 23A256T-I/ST enables direct 1.8 V integration and cuts standby power by >99%, while FM25V20-G trades SRAM volatility for infinite write endurance at the expense of voltage flexibility and package options.
Availability
23A256T-I/ST is available at Aetrix Electronics and suitable for medical wearables, industrial PLC modules, smart meter data loggers, and automotive body control units requiring stable component supply across extended product lifecycles.
Supply support for 23A256T-I/ST includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology Inc. is a leading provider of microcontroller, mixed-signal, analog, and Flash-IP solutions, serving industrial, automotive, consumer, and communications markets with high-reliability silicon and development tools.
The 23X256 family was designed specifically to deliver low-voltage, low-power, SPI-compatible serial SRAM for resource-constrained embedded systems where board space, energy budget, and interrupt-safe communication are critical design constraints.
FAQ
What is the minimum supply voltage required to retain data in the 23A256T-I/ST?
The 23A256T-I/ST guarantees RAM data retention down to 1.2 V (VDR parameter), meaning stored contents remain intact even during brown-out conditions as low as 1.2 V, provided the device remains powered and temperature stays within −40°C to +85°C. This value is verified per DS22100F, Table 1-1, Param. D011.
Does the 23A256T-I/ST support true SPI Mode 0 (CPOL = 0, CPHA = 0)?
Yes, the 23A256T-I/ST operates exclusively in SPI Mode 0: data is sampled on the rising edge of SCK (CPHA = 0) and clock idles low (CPOL = 0). This is confirmed in DS22100F Section 2.1 and Figure 2-1 through 2-8, where SI latching occurs on SCK rising edge and SO updates after SCK falling edge.
How does the HOLD function interact with the STATUS register in the 23A256T-I/ST?
The HOLD function in the 23A256T-I/ST is disabled unless the HOLD bit (bit 0) in the STATUS register is cleared to '0'. When set to '1', the HOLD pin is ignored. This behavior is explicitly defined in DS22100F Section 2.5 and Table 2-2, and applies to all 23A256T-I/ST operations regardless of mode.
Can the 23A256T-I/ST be used in automotive applications requiring AEC-Q200 qualification?
No - the 23A256T-I/ST is rated for Industrial temperature (−40°C to +85°C) only and is not AEC-Q200 qualified. For automotive use, Microchip offers the 23K256-E/ST variant (−40°C to +125°C, AEC-Q200 compliant), which shares identical pinout and protocol but requires 2.7–3.6 V supply.
What is the maximum supported clock frequency for the 23A256T-I/ST at 1.5 V supply?
At VCC = 1.5 V, the 23A256T-I/ST supports up to 10 MHz clock frequency, as specified in DS22100F Table 1-2, Param. No. 1 (FCLK). Performance scales with voltage: 16 MHz at 1.8 V, 20 MHz at 1.8 V (I-temp), and 16 MHz at 3.0 V (E-temp) for the 23K256 variant.
23A256T-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- Volatile
- Memory Format:
- SRAM
- Technology:
- SRAM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- SPI
- Clock Frequency:
- 20 MHz
- Write Cycle Time - Word, Page:
- -
- Access Time:
- -
- Voltage - Supply:
- 1.7V ~ 1.95V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
23A256T-I/ST FAQ
1.How can I place an order for 23A256T-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 23A256T-I/ST on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for 23A256T-I/ST reliable?
The price and inventory of 23A256T-I/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 23A256T-I/ST is usually 5 days.
3.What payment methods are accepted for 23A256T-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 23A256T-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 23A256T-I/ST?
23A256T-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 23A256T-I/ST order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for 23A256T-I/ST?
For technical support, including 23A256T-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 23A256T-I/ST requirements.
6.How does Aetrix verify that 23A256T-I/ST is sourced from the original manufacturer or authorized distributors?
All 23A256T-I/ST products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 23A256T-I/ST meets industry standards.
7.What is the process for return or replacement of 23A256T-I/ST?
All 23A256T-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 23A256T-I/ST, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The 23A256T-I/ST part is unused and in its original packaging.
Return procedure for 23A256T-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
23A256T-I/ST Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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AT24C08C-STUM-T
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