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Infineon Technologies CY7C138-25JXC
- Part No.:
- CY7C138-25JXC
- Manufacturer:
- Infineon Technologies
- Category:
- Memory
- Package:
- 68-LCC (J-Lead)
- Datasheet:
-
CY7C138-25JXC.pdf
- Description:
- IC SRAM 32KBIT PARALLEL 68PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,327
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Product details
Overview
CY7C138-25JXC from Cypress Semiconductor is a 4K × 8 true dual-port static RAM with independent left/right ports, 25 ns access time, TTL-compatible I/O, and on-chip semaphore logic for interprocessor synchronization in real-time embedded systems.
For engineers reviewing the CY7C138-25JXC datasheet, CY7C138-25JXC pinout, CY7C138-25JXC application, or CY7C138-25JXC equivalent, key selection factors include simultaneous asynchronous port access, BUSY/INT flag timing (tBLA ≤ 20 ns), M/S master/slave expansion capability, and PLCC-68 packaging for legacy industrial control designs.
Technical Context
The CY7C138-25JXC implements fully asynchronous dual-port operation with separate CE/R/W/OE controls per port and hardware arbitration via BUSY flag assertion on address collision. Its 0.65-μm CMOS process enables 25 ns read/write cycle times while maintaining TTL-level compatibility across all I/O pins.
On-chip semaphores consist of eight shared latches controlled by SEML/SEMR and A0–A2; INTL/INTR flags support mailbox-style inter-port communication using fixed addresses FFEH/FFFH. The M/S pin enables 16-bit+ memory expansion without external logic by configuring master/slave device roles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory organization | 4K × 8 bits (32,768 total bits), enabling byte-wide data exchange between two independent processors |
| Access time | 25 ns maximum - guarantees deterministic latency for real-time interrupt response in dual-CPU systems |
| Supply voltage | 5 V ±10% - compatible with standard TTL logic rails and legacy industrial power supplies |
| Operating current | 180 mA max (commercial) - supports thermal management in dense PCB layouts without forced cooling |
| Standby current ISB1 | 40 mA max (commercial, both ports disabled) - reduces power in idle states during multi-processor handshaking |
| I/O voltage levels | TTL-compatible (VIH ≥ 2.2 V, VIL ≤ 0.8 V) - ensures direct interfacing with 74LS/ALS logic families |
| Capacitance | CIN = 10 pF, COUT = 15 pF - limits signal integrity degradation at 25 ns timing margins |
Pinout & Package
Package: 68-pin plastic leaded chip carrier (PLCC), surface-mount, RoHS-compliant, with exposed thermal pad not present (standard PLCC-68 footprint).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A11L / A0R–A11R | Address inputs (left/right) | 12-bit independent addressing per port; enables full 4K space access from either side without contention |
| I/O0L–I/O7L / I/O0R–I/O7R | Bidirectional data bus (left/right) | Byte-wide parallel interface; supports simultaneous read/write if accessing different addresses |
| CEL / CER | Chip enable (left/right) | Active-low port activation; enables independent power-down per port via automatic ISB3 mode |
| OEL / OER | Output enable (left/right) | Controls three-state output drivers; tLZOE ≤ 3 ns ensures fast bus release during arbitration |
| R/WL / R/WR | Read/write control (left/right) | Determines data direction per port; tLZWE ≤ 3 ns minimizes write-to-read turnaround delay |
| SEML / SEMR | Semaphore enable (left/right) | Activates access to eight shared latches; A0–A2 select latch; I/O0 used for write data |
| INTL / INTR | Interrupt flag (left/right) | Push-pull outputs (no pull-up required); INTL set by right-port write to FFEH, cleared by left-port read |
| BUSYL / BUSYR | Busy flag (left/right) | Indicates address collision; BUSY asserted within 20 ns (tBLA) when both ports access same location |
| M/S | Master/slave select | Configures device role for 16-bit+ expansion; eliminates need for discrete priority logic in multi-chip systems |
Key Features
| Feature | Design Value |
|---|---|
| True dual-port architecture | Enables concurrent reads from identical memory locations - critical for status mirroring in redundant controllers |
| Hardware semaphore logic | Eight dedicated latches with atomic request/grant protocol prevent race conditions in shared resource allocation |
| Asynchronous port control | Fully independent CE/R/W/OE per port allows mismatched timing domains (e.g., 8051 + DSP) to coexist on one RAM |
| Interrupt mailbox mechanism | Fixed-address INT triggers (FFE/FFF) provide zero-latency inter-processor signaling without polling overhead |
| Automatic power-down | Per-port standby modes (ISB1–ISB4) reduce current to 15 mA when CE inactive - extends uptime in battery-backed systems |
Applications
| Industrial PLC Backplane Buffer | Avionics Dual-Redundant CPU Interface |
|---|---|
|
Use Scenario: Two independent PLC CPUs share I/O status and motion control parameters via common memory. IC Role / Device Role / Timing Role: Dual-port SRAM acts as non-blocking shared register bank with BUSY arbitration preventing corrupted writes during scan cycles. Use Value: 25 ns access ensures sub-millisecond update latency between CPUs, meeting IEC 61131-3 cyclic task timing requirements. |
Use Scenario: Primary and backup flight control computers maintain synchronized state tables for failover readiness. IC Role / Device Role / Timing Role: CY7C138-25JXC serves as fault-tolerant data exchange buffer with INT-driven mailbox for health status updates. Use Value: Push-pull INT outputs eliminate external pull-ups, reducing component count in DO-254-certifiable hardware. |
| Medical Imaging Frame Buffer | Legacy Telecom Protocol Processor |
|
Use Scenario: Image acquisition engine writes raw pixel data while display controller reads processed frames. IC Role / Device Role / Timing Role: Acts as ping-pong frame buffer with semaphore-controlled buffer switching to avoid tearing artifacts. Use Value: On-chip semaphores eliminate software mutex overhead, enabling deterministic 60 Hz video refresh in real-time OS environments. |
Use Scenario: TDM switch fabric processor and channel bank ASIC coordinate call setup via shared configuration registers. IC Role / Device Role / Timing Role: Provides low-latency inter-ASIC communication path with M/S expansion supporting 32-bit data paths. Use Value: PLCC-68 package matches legacy telecom board layouts, avoiding redesign costs in field-replaceable line cards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT7134SA25YG | 4K × 8, 25 ns, 5 V, but uses 52-pin SOJ package and lacks M/S pin for master/slave expansion | Requires external logic for >8-bit bus width; no integrated semaphore arbitration | Select when board space constraints favor SOJ and semaphore logic is implemented in FPGA |
| ISSI IS61LV25616AL-25TQLI | 256K × 16, 25 ns, 3.3 V only; incompatible voltage domain and larger density | Not drop-in replaceable due to VCC mismatch and 100-pin TQFP packaging | Consider only for new 3.3 V designs requiring higher density and willing to redesign power and layout |
Compared with IDT7134SA25YG and IS61LV25616AL-25TQLI, CY7C138-25JXC uniquely combines PLCC-68 packaging, 5 V TTL compatibility, M/S expansion, and integrated semaphores - making it irreplaceable in legacy industrial backplanes where mechanical and electrical form-factor alignment is mandatory.
Availability
CY7C138-25JXC is available at Aetrix Electronics and suitable for industrial PLC backplanes, avionics redundancy interfaces, and medical imaging subsystems requiring stable component supply across extended product lifecycles.
Supply support for CY7C138-25JXC 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
Cypress Semiconductor (now part of Infineon Technologies) designs high-reliability memory and programmable solutions for industrial, automotive, and aerospace applications.
The CY7C138 belongs to Cypress's legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in safety-critical real-time systems with strict timing and packaging constraints.
FAQ
Is CY7C138-25JXC pin-compatible with CY7C137-25JXC?
No. CY7C137-25JXC is a 4K × 9 dual-port SRAM with an extra data bit (I/O8) and different pin assignments for parity-related signals. The CY7C138-25JXC has no parity support and allocates those pins to ground or NC, making direct substitution electrically and mechanically invalid.
Can the BUSY flag be disabled to force unconditional access?
No. BUSY is hardwired arbitration logic - it cannot be disabled. When both ports attempt access to the same address, BUSY asserts within 20 ns (tBLA) and holds until one port completes its cycle. This behavior is intrinsic to the silicon design and ensures data coherency.
What is the maximum clock frequency supported for continuous read/write cycling?
The device has no internal clock; it is fully asynchronous. Maximum sustained operation is governed by tRC = 25 ns, yielding an effective upper limit of 40 MHz for repetitive read or write cycles - provided address and control setup/hold times (e.g., tSA = 0 ns, tHA = 2 ns) are met by the driving logic.
Does the PLCC-68 package support reflow soldering?
Yes. CY7C138-25JXC in PLCC-68 is qualified for IR reflow per J-STD-020, with peak temperature up to 225 °C. The plastic body is rated for moisture sensitivity level (MSL) 3, requiring bake-out if exposed to ambient >60% RH for >168 hours before reflow.
CY7C138-25JXC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Infineon Technologies
- Series:
- -
- Package/Case:
- 68-LCC (J-Lead)
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Volatile
- Memory Format:
- SRAM
- Technology:
- SRAM - Dual Port, Asynchronous
- Memory Size:
- 32Kbit
- Memory Organization:
- 4K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 25ns
- Access Time:
- 25 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 68-PLCC (24.23x24.23)
CY7C138-25JXC FAQ
1.How can I place an order for CY7C138-25JXC through Aetrix?
Please submit a Request for Quotation (RFQ) for CY7C138-25JXC 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 CY7C138-25JXC reliable?
The price and inventory of CY7C138-25JXC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY7C138-25JXC is usually 5 days.
3.What payment methods are accepted for CY7C138-25JXC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY7C138-25JXC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CY7C138-25JXC?
CY7C138-25JXC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CY7C138-25JXC 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 CY7C138-25JXC?
For technical support, including CY7C138-25JXC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY7C138-25JXC requirements.
6.How does Aetrix verify that CY7C138-25JXC is sourced from the original manufacturer or authorized distributors?
All CY7C138-25JXC 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 CY7C138-25JXC meets industry standards.
7.What is the process for return or replacement of CY7C138-25JXC?
All CY7C138-25JXC units undergo pre-shipment inspection (PSI). If there is an issue with CY7C138-25JXC, 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 CY7C138-25JXC part is unused and in its original packaging.
Return procedure for CY7C138-25JXC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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