AT25320B-SSHL-T - 32Kbit SPI EEPROM, 20MHz, 8-SOIC | Microchip
MPN: AT25320B-SSHL-T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.55 | $5.50 |
| 100 | $0.42 | $42.00 |
| 500 | $0.34 | $170.00 |
| 1,000 | $0.28 | $280.00 |
| 3,000 | $0.23 | $690.00 |
AT25320B-SSHL-T Overview
A serial EEPROM (Electrically Erasable Programmable Read-Only Memory) is a type of non-volatile memory that retains data without power and is accessed serially through a small pin count. SPI EEPROMs belong to the broader hierarchy of memory ICs -> non-volatile memory (NVM) -> EEPROM -> serial EEPROM -> SPI EEPROM, and are widely used as configuration, calibration, user-data, and black-box storage on PCBs where small density, low pin count, and byte-level write granularity are required.
Key features include: 32 Kbit density (4096 x 8), 20 MHz maximum SPI clock rate at 5V, byte and 32-byte page write modes, hardware/software write protection via /WP and /HOLD pins, and 1,000,000 erase/write cycles endurance typical with >100 year data retention. The device supports status register read and a sequential read mode that allows the entire array to be read with a single read command.
Internally, the AT25320B uses a CMOS floating-gate EEPROM cell with on-chip charge pump for high-voltage generation during programming. The SPI slave interface uses dedicated pins CS#, SCK, SI (MOSI), and SO (MISO), with /WP and /HOLD providing additional bus-sharing flexibility. The architecture is optimized for low-power operation, drawing microamp-level standby currents.
Typical applications include consumer electronics parameter storage, industrial sensor calibration, medical device patient-data logging, automotive infotainment HMI settings, IoT device configuration, and any embedded system needing persistent small-data storage with low power and low pin count. The wide 2.5V-5.5V range lets it share a bus with both 3.3V MCUs and 5V legacy logic.
When designing with this part, place a 0.1uF decoupling capacitor close to VCC, keep CS# low during any SPI transaction, and observe the write cycle time (typically 5 ms) before polling the status register for completion. Always tie unused /WP and /HOLD to VCC for normal operation.
This page synthesizes distributor pricing, drop-in SPI EEPROM alternatives in the same 8-SOIC footprint, and practical hardware design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for AT25320B-SSHL-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with AT25320B-SSHL-T (same form factor and footprint) — differing in Data Retention, MSL Level, Maximum Clock Frequency, Memory Density, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
25AA320-I/SN
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AT25320B-SSHL-B
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AT25320B-MAHL-T
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
25LC320-I/SN
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
CAT25320VI-GT3
✅ Drop-In📋 Reference alternative (not in catalog)
M95320-WMN6TP
✅ Drop-In📋 Reference alternative (not in catalog)
BR25H320-W
✅ Drop-In📋 Reference alternative (not in catalog)
AT25320B-SSHL-T Specifications
| Memory Type | Non-volatile EEPROM (Serial) |
| Memory Density | 32 Kbit (4,096 x 8-bit) |
| Organization | 4,096 words x 8 bits |
| Interface | SPI (Serial Peripheral Interface) |
| SPI Modes Supported | Mode 0 (0,0) and Mode 3 (1,1) |
| Maximum Clock Frequency | 20 MHz at 5V |
| Supply Voltage Range | 2.5 V to 5.5 V |
| Write Cycle Time | 5 ms (typical, page/byte write) |
| Page Size | 32 bytes |
| Write Endurance | 1,000,000 erase/write cycles (typical) |
| Data Retention | >100 years (typical) |
| Write Protection | Hardware (/WP pin) and software block protection (upper 1/4, upper 1/2, full array) |
| Operating Temperature Range | -40C to +85C (industrial, per -SSH suffix) |
| Package | 8-SOIC (0.150 inch body, JEDEC SO-8) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
| Packaging | Tape & Reel (per -T suffix) |
AT25320B-SSHL-T Pin Configuration
| Pin 1 | CS# — Chip Select, active low. Enables SPI communication when pulled low; tied high places device in standby. |
| Pin 2 | SO — Serial Data Out (MISO). Outputs data from the EEPROM during read operations. |
| Pin 3 | /WP — Write Protect, active low. Tie to VCC to enable writes; tie to GND to inhibit all write operations to the status register and array. |
| Pin 4 | GND — Ground reference. |
| Pin 5 | SI — Serial Data In (MOSI). Receives opcode, address, and data from the SPI master. |
| Pin 6 | SCK — Serial Clock. Driven by the SPI master; supports up to 20 MHz at 5V. |
| Pin 7 | /HOLD — Hold, active low. Pauses SPI communication without deselecting the device; tie to VCC if unused. |
| Pin 8 | VCC — Power supply, 2.5V to 5.5V. Decouple with 0.1uF ceramic capacitor placed close to the pin. |
Typical Applications
AT25320B-SSHL-T is suitable for 6 applications: Consumer Electronics Configuration Storage, Industrial Sensor Calibration Storage, Medical Device Patient-Data Logging, Automotive Infotainment HMI Settings, IoT Device Configuration & Identity, White Goods & Appliance User Interface Memory.
Consumer Electronics Configuration Storage
The AT25320B-SSHL-T is well suited for storing device configuration parameters in consumer electronics such as set-top boxes, smart appliances, and remote controls. Its 4,096-byte density is ample for user preferences, channel lists, calibration coefficients, and last-state memory, while the SPI bus at 20 MHz lets the host MCU boot and read settings in under 5 ms. The 2.5V-5.5V supply range supports both 3.3V ARM Cortex-M hosts and older 5V microcontrollers without level translation. Hardware write-protect via /WP prevents accidental corruption during firmware updates, and 1M erase/write cycles ensure years of user-setting updates without endurance concerns.
Recommended
Industrial Sensor Calibration Storage
In industrial sensor modules (pressure, flow, temperature, gas), the AT25320B-SSHL-T stores factory calibration coefficients and user trim values that must survive power cycles and harsh environments. The 8-SOIC package is robust for hand-soldering during sensor module assembly, and the -40C to +85C industrial temperature range covers most factory-floor and outdoor installations. Each sensor can be calibrated once at factory, then the host reads calibration data at every power-up to compensate the raw ADC reading. The 100-year data retention far exceeds the typical 10-year service life of industrial sensor modules.
Recommended
Medical Device Patient-Data Logging
For portable medical devices such as blood-glucose meters, pulse oximeters, and ambulatory ECG monitors, the AT25320B-SSHL-T serves as a small non-volatile log for last-session data, patient ID, and measurement history. Its low standby current (<1uA) preserves battery life between patient sessions, and the SPI bus permits the host MCU to log measurements every few seconds without bus contention. The 32-byte page write mode allows efficient batch log updates. Compliance with RoHS and 100-year data retention support the documentation requirements for medical device regulatory submissions. The wide 2.5V-5.5V range simplifies battery-direct designs without boost converters.
Recommended
Automotive Infotainment HMI Settings
The AT25320B-SSHL-T is used in automotive infotainment head units and HVAC control modules to retain user preferences (seat position, mirror settings, radio presets, climate zones) across key-off cycles. While the industrial-grade AT25320B-SSHL-T is rated -40C to +85C, Microchip offers the AT25320B-SSHL-T-577 automotive-qualified variant for under-hood applications requiring AEC-Q100. The SPI interface integrates easily with NXP i.MX and Renesas RH850 application processors used in modern head units. Fast 20 MHz reads let the HMI restore settings within 100 ms of CAN bus wake-up, before the display is even fully on.
Recommended
IoT Device Configuration & Identity
In IoT endpoint devices (smart thermostats, asset trackers, environmental monitors), the AT25320B-SSHL-T stores Wi-Fi credentials, device certificates, manufacturing ID, and last-known-good configuration for OTA rollback. Its small 8-SOIC footprint fits on space-constrained sensor PCBs alongside the radio module and MCU. The 20 MHz SPI bus allows fast boot-time credential retrieval, and the software write-protect blocks (upper 1/4, 1/2, full) protect OTA staging regions from corruption. Low standby current preserves battery life on intermittently-powered edge sensors.
Recommended
White Goods & Appliance User Interface Memory
Washing machines, dishwashers, ovens, and refrigerators use the AT25320B-SSHL-T to store cycle parameters, error logs, and service history that must survive decades of mains-bumpy operation. The robust 8-SOIC package withstands wave-soldering and the wide supply voltage handles 5V rectified rails common in appliance designs. Service technicians can read the error log via SPI to diagnose intermittent failures, while the 1M erase/write cycle endurance handles daily cycle-program updates over a 10+ year product lifetime.
Recommended
Recommended Products Summary
Engineering reference data for AT25320B-SSHL-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 25AA320-I/SN | 25LC320-I/SN | CAT25320VI-GT3 | M95320-WMN6TP | BR25H320-W |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | onsemi | STMicroelectronics | ROHM Semiconductor |
| Package | 8-SOIC (0.150 inch) | 8-SOIC (0.150 inch) - same | 8-SOIC (0.150 inch) - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same |
| Density | 32 Kbit (4 KB) | 32 Kbit (4 KB) | 32 Kbit (4 KB) | 32 Kbit (4 KB) | 32 Kbit (4 KB) | 32 Kbit (4 KB) |
| Max SPI Clock | 20 MHz at 5V | 10 MHz (-50%) | 2 MHz (-90%) | 10 MHz (-50%) | 20 MHz (same) | 10 MHz (-50%) |
| Supply Voltage | 2.5V to 5.5V | 1.8V to 5.5V (wider low end) | 2.5V to 5.5V (same) | 2.5V to 5.5V (same) | 2.5V to 5.5V (same) | 2.5V to 5.5V (same) |
| Page Size | 32 bytes | 32 bytes (same) | 32 bytes (same) | 32 bytes (same) | 32 bytes (same) | 32 bytes (same) |
| Write Endurance | 1M cycles | 1M cycles (same) | 1M cycles (same) | 1M cycles (same) | 1M cycles (same) | 1M cycles (same) |
| Approx. Unit Price (qty 1,000) | $0.28 | ~$0.32 | ~$0.30 | ~$0.26 | ~$0.31 | ~$0.35 |
| Operating Temperature | -40C to +85C | -40C to +85C (same) | -40C to +85C (same) | -40C to +85C (same) | -40C to +85C (same) | -40C to +40C (narrower) |
Key Differentiators
- Highest SPI clock speed in 32 Kbit 8-SOIC EEPROM family (vs 25AA320-I/SN)
- Wide 2.5V-5.5V supply with same 20 MHz speed as ST alternative (vs M95320-WMN6TP)
- Lower price than onsemi cross-reference (vs CAT25320VI-GT3)
Design Notes
Place a 0.1uF X7R ceramic decoupling capacitor within 3 mm of the VCC pin (Pin 8), with the ground end returning directly to the GND pin (Pin 4) via a short, wide trace. The AT25320B-SSHL-T draws brief current spikes during write cycles (peak ~3 mA for ~5 ms), and insufficient decoupling causes VCC droop that can corrupt the write or trigger false write-protect assertion. For 5V systems with noisy switching regulators upstream, add a 10uF tantalum or polymer cap in parallel.
Route the SPI bus (SCK, SI, SO) as a short matched-length group within 25 mm of the host MCU to avoid signal integrity issues at 20 MHz. Keep CS# as a dedicated GPIO, not shared with other peripherals, to prevent bus contention. The /WP and /HOLD pins must be tied to VCC (not left floating) if write protection and hold functions are not used; floating inputs can pick up noise and inadvertently assert protection or pause the bus.
After issuing a WRITE or PAGE WRITE command, the host MUST wait at least 5 ms (tWC) before polling the status register or initiating another write. Polling earlier can cause data corruption or bus contention. Use the built-in status register polling method (read STATUS with /CS low, check bit 0 transitions) rather than fixed delays for faster write turnaround. Also note: the AT25320B does NOT support sequential multi-page writes in a single command - each page write must complete before the next begins.
Place the AT25320B-SSHL-T on the same PCB side as the host MCU with no vias under the SOIC pads to simplify inspection and rework. Keep the EEPROM at least 5 mm away from switching converter inductors and high-current traces to avoid coupling of switching noise into the SPI bus, which can manifest as read errors at 20 MHz. If the design must place the EEPROM near a noisy region, add a ground guard ring around the IC and stitch GND vias every 3 mm around the package perimeter.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified - choose AT25320B-SSHL-T-577 automotive variant for AEC-Q100 requirements. Halogen-free per Microchip material declaration. Conflict minerals compliant under Dodd-Frank Section 1502.
