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Infineon Technologies CY7C138-25JC
- Part No.:
- CY7C138-25JC
- Manufacturer:
- Infineon Technologies
- Category:
- Memory
- Package:
- 68-LCC (J-Lead)
- Datasheet:
-
CY7C138-25JC.pdf
- Description:
- IC SRAM 32KBIT PARALLEL 68PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,821
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Product details
Overview
CY7C138-25JC 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/interrupt/busy arbitration logic. It enables simultaneous asynchronous read/write access to shared memory in multiprocessor interconnects and video buffering systems.
For engineers reviewing the CY7C138-25JC datasheet, CY7C138-25JC pinout, CY7C138-25JC application, or CY7C138-25JC equivalent, key selection criteria include dual-port arbitration behavior, 68-pin PLCC package compatibility, 5 V ±10% supply operation, and port-to-port timing parameters (tWDD = 50 ns, tDDD = 30 ns) for interprocessor mailbox design.
Technical Context
The CY7C138-25JC implements fully asynchronous dual-port architecture with separate address, data, and control buses per port (A0L–A11L/I/O0L–I/O7L/CEL/OEL/R/WL and A0R–A11R/I/O0R–I/O7R/CER/OER/R/WR). Arbitration is handled by hardware BUSY flag generation and software-controlled semaphores (eight shared latches).
Interrupt signaling uses dedicated INTL/INTR pins with fixed mailbox addresses (FFEh/FFFh), while M/S pin enables master/slave expansion to 16-bit+ data width without external logic. Power management includes per-port automatic power-down via CE or SEM assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 4K × 8 bits (32,768 total bits), two independent addressable spaces |
| Access Time | 25 ns maximum - determines minimum processor bus cycle duration for reliable read/write |
| Supply Voltage | 5 V ±10% - compatible with legacy TTL and 5 V CMOS system rails |
| Operating Current | 160 mA max (ICC) - defines thermal budget and regulator sizing for sustained dual-port activity |
| Standby Current | 30 mA max (ISB1, both ports disabled) - enables low-power idle states in battery-backed or intermittent-use systems |
| I/O Voltage Levels | VIH = 2.2 V min, VIL = 0.8 V max - ensures robust noise margin against TTL-level signal sources |
| Output Drive | IOH = –4 mA / IOL = 4 mA - supports direct connection to standard TTL loads without buffers |
Pinout & Package
68-pin Plastic Leaded Chip Carrier (PLCC) package with gull-wing leads, RoHS-compliant Pb-free option available. Pin 1 identified by corner notch; top-side marking includes "CY7C138-25JC" and date code.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A11L | Left port address inputs | 12-bit address bus selecting one of 4K locations for left-side access |
| A0R–A11R | Right port address inputs | Independent 12-bit address bus for concurrent right-side memory access |
| I/O0L–I/O7L | Left port bidirectional data bus | 8-bit parallel data path; high-impedance when OEL = HIGH or CEL = HIGH |
| I/O0R–I/O7R | Right port bidirectional data bus | Independent 8-bit data path; isolated from left port during arbitration contention |
| CEL, CER | Chip enable (active LOW) | Per-port power-down control; disables outputs and reduces ICC to ISB1/ISB2 levels |
| OEL, OER | Output enable (active LOW) | Tri-states I/O bus independently of CE; enables output gating without disabling core logic |
| R/WL, R/WR | Read/write control (active LOW = write) | Determines data direction per port; must be stable during address setup and hold windows |
| INTL, INTR | Interrupt flags (push-pull) | No pull-up required; INTL set by right-port write to FFEh, cleared by left-port read of FFEh |
| BUSYL, BUSYR | Busy status indicators | Signal port-level contention: BUSYL = LOW when left port attempts access to location busy on right port |
| SEML, SEMR | Semaphore enable (active LOW) | Enables access to eight shared semaphore latches using A0–A2 as select lines; I/O0 used for read/write |
| M/S | Master/slave mode select | LOW = master (BUSY output), HIGH = slave (BUSY input); enables 16-bit+ expansion without discrete logic |
| VCC, GND | Power and ground | Single 5 V supply; decoupling required at each VCC pin per high-speed CMOS layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| True dual-port memory cells | Enables simultaneous reads from same address on both ports - eliminates arbitration delay for shared status polling |
| Hardware BUSY flag generation | Automatic per-port BUSY assertion on address collision - prevents data corruption without software overhead |
| Eight on-chip semaphores | Shared latches controllable via SEML/SEMR + A0–A2 - provides atomic resource locking across processors |
| Mailbox-style interrupt signaling | Fixed-address INTL/INTR toggle (FFEh/FFFh) - enables zero-latency interprocessor notification without polling |
| Master/slave expansion mode | M/S pin configures device as master (BUSY output) or slave (BUSY input) - simplifies 16-bit+ memory construction |
Applications
| Interprocessor Communication | Video Frame Buffering |
|---|---|
|
Use Scenario: Two microcontrollers exchange real-time sensor data and control commands via shared memory. IC Role / Device Role / Timing Role: Dual-port RAM acts as synchronized mailbox with semaphore-controlled access and INT-driven event signaling. Use Value: Eliminates need for external arbitration logic; 25 ns access enables sub-40 MHz processor bus synchronization. |
Use Scenario: Graphics controller writes rendered frames while display engine reads previous frame for scanout. IC Role / Device Role / Timing Role: Memory serves as ping-pong buffer with independent read/write ports preventing display tearing. Use Value: True dual-port architecture allows concurrent write/read of same address - no wait states during frame swaps. |
| Communications Protocol Stack | Industrial PLC Data Exchange |
|
Use Scenario: Modem baseband processor and host CPU share packet buffers for TCP/IP offload. IC Role / Device Role / Timing Role: RAM provides low-latency, deterministic data transfer between protocol layers with BUSY-interrupt handshaking. Use Value: Hardware arbitration ensures packet integrity under burst traffic; 30 mA standby current supports low-power sleep modes. |
Use Scenario: PLC main CPU and I/O coprocessor coordinate analog/digital I/O updates via shared register map. IC Role / Device Role / Timing Role: Acts as deterministic shared memory with semaphore-based resource locking for I/O configuration registers. Use Value: On-chip semaphores prevent race conditions during configuration changes; 5 V tolerance matches industrial I/O voltage rails. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT70V25L25PF | 3.3 V supply only; 25 ns access; 4K × 8 organization; LVDS-compatible I/O | Requires level-shifting for 5 V systems; lower power but incompatible with TTL-level peripherals | Select when migrating to 3.3 V infrastructure and requiring lower ICC (90 mA typical) |
| ISSI IS61LV25616AL-10TLI | Single-port, 256K × 16; 10 ns access; 3.3 V supply; no built-in arbitration | Lacks semaphores, BUSY, INT; requires external logic for dual-processor coordination | Choose only if application uses external arbitration and prioritizes density/speed over integrated features |
Compared with IDT70V25L25PF and IS61LV25616AL-10TLI, the CY7C138-25JC uniquely delivers 5 V TTL compatibility, hardware arbitration, and mailbox interrupts in a single 68-pin PLCC - reducing BOM count and PCB area in legacy industrial designs.
Availability
CY7C138-25JC is available at Aetrix Electronics and suitable for interprocessor communication, video frame buffering, communications protocol stacks, and industrial PLC data exchange requiring stable component supply across extended temperature ranges.
Supply support for CY7C138-25JC 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 logic solutions for industrial, automotive, and communications markets.
The CY7C138 series targets legacy 5 V embedded systems requiring deterministic dual-processor memory sharing without external arbitration logic - emphasizing pin compatibility, timing predictability, and long-lifecycle support.
FAQ
What is the function of the M/S pin on CY7C138-25JC?
The M/S pin configures the device as master (M/S = LOW) or slave (M/S = HIGH) for multi-chip expansion. In master mode, BUSYL/BUSYR are outputs; in slave mode, BUSYL is an input. This enables 16-bit or wider dual-port memory without external glue logic or discrete bus transceivers.
How do the semaphore latches operate in CY7C138-25JC?
Eight semaphore latches are accessed via SEML/SEMR assertion with A0–A2 selecting the latch. Writing 0 to a latch requests it; reading returns its state. Only one port can control a given latch at a time, enabling atomic resource locking. I/O0L/I/O0R carries semaphore data during access.
Can CY7C138-25JC operate in industrial temperature range?
Yes - the -25JC suffix denotes industrial grade (-40°C to +85°C) operation with 5 V ±10% supply. Electrical specifications including ICC (180 mA max), ISB1 (40 mA max), and timing parameters (tRC = 25 ns) are guaranteed across this full range per datasheet Rev. *B.
What is the timing relationship between BUSY assertion and address matching?
BUSY asserts LOW within 15–20 ns (tBLA) after both ports drive identical addresses. It remains asserted until the contending port completes its cycle. The BUSY signal is synchronous to the local port's clock domain and does not require external synchronization for use in handshake protocols.
CY7C138-25JC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Infineon Technologies
- Series:
- -
- Package/Case:
- 68-LCC (J-Lead)
- Packaging:
- Tube
- 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)
CY7C138-25JC FAQ
1.How can I place an order for CY7C138-25JC through Aetrix?
Please submit a Request for Quotation (RFQ) for CY7C138-25JC 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 CY7C138-25JC reliable?
The price and inventory of CY7C138-25JC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY7C138-25JC is usually 5 days.
3.What payment methods are accepted for CY7C138-25JC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY7C138-25JC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CY7C138-25JC?
CY7C138-25JC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CY7C138-25JC 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 CY7C138-25JC?
For technical support, including CY7C138-25JC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY7C138-25JC requirements.
6.How does Aetrix verify that CY7C138-25JC is sourced from the original manufacturer or authorized distributors?
All CY7C138-25JC 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 CY7C138-25JC meets industry standards.
7.What is the process for return or replacement of CY7C138-25JC?
All CY7C138-25JC units undergo pre-shipment inspection (PSI). If there is an issue with CY7C138-25JC, 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 CY7C138-25JC part is unused and in its original packaging.
Return procedure for CY7C138-25JC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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