PSD834F2V-20MI - 2Mb Flash PSD, 3.3V, 200ns, 52-PQFP | STMicroelectronics
MPN: PSD834F2V-20MI ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.25 | $112.50 |
| 100 | $9.85 | $985.00 |
| 500 | $8.4 | $4,200.00 |
| 1,000 | $7.15 | $7,150.00 |
PSD834F2V-20MI Overview
What is a Flash PSD? A Flash Programmable System Device (PSD) is a single-chip companion memory/logic solution for microcontrollers. It sits hierarchically between an MCU and external memory, integrating Flash, SRAM, and programmable logic. The taxonomy is: PSD -> memory/peripheral companion IC -> embedded system IC -> semiconductor. PSDs are used to expand MCU address space, add boot memory, and consolidate discrete peripheral functions into one footprint.
Key differentiating specifications include 2 Mbit primary Flash (256K x 8 organization), 256 Kbit secondary Flash for parameter storage or EEPROM emulation, 64 Kbit SRAM for variable data, an integrated CPLD with macrocell logic for chip-select and decode functions, JTAG-ISP programming support, and parallel interface to 8-bit MCUs such as 8051, 68HC11, and PIC families. The single 3.3V supply simplifies power tree design versus dual-supply memories.
Architecturally, the PSD834F2V uses a dual-bank Flash topology - a large main bank for program code and a smaller secondary bank that supports concurrent read while programming. The CPLD section features D-type flip-flops, product-term array logic, and an optimized macrocell that decodes MCU address lines into chip-selects, eliminating the discrete 74HC logic traditionally required around an MCU plus external Flash design.
Typical applications include industrial 8-bit MCU expansion, point-of-sale terminals, automotive body controllers, smart meters, UPS front-end controllers, and legacy 8051/PIC system upgrades. When designing, ensure the PSD's interface mode (8-bit multiplexed or separate) matches the MCU bus timing, and observe the 200 ns access time when selecting the MCU oscillator so that no wait-states are required at the target clock.
Drop-in alternatives for PSD834F2V-20MI — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PSD834F2V-15M
✅ Drop-In📋 Reference alternative (not in catalog)
PSD834F2V-20JI
✅ Drop-In📋 Reference alternative (not in catalog)
PSD834F2V-15J
✅ Drop-In📋 Reference alternative (not in catalog)
PSD834F2V-12M
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PSD834F2-70M
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PSD834F2V-20U
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PSD834F2V-20MI Maximum Ratings & Electrical Characteristics
| Memory Type | Flash (Non-Volatile) |
| Memory Size | 2 Mbit (256K x 8) primary + 256 Kbit secondary |
| SRAM Size | 64 Kbit |
| Organization | 256K x 8 |
| Interface | Parallel (8-bit MCU) |
| Access Time | 200 ns |
| Supply Voltage | 3.0 V to 3.6 V (3.3 V nominal) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | 52-PQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Programmability | In-System Programmable (ISP) via JTAG |
| Integrated Logic | CPLD macrocell block for address decode and chip-selects |
| Target MCUs | 8-bit (8051, 68HC11, PIC, etc.) |
PSD834F2V-20MI Pin Configuration
| Pin 1 | VCC — 3.3V power supply |
| Pin 2 | GND — Ground |
| Pin 3 | AD0 — MCU address/data bit 0 |
| Pin 4 | AD1 — MCU address/data bit 1 |
| Pin 5 | AD2 — MCU address/data bit 2 |
| Pin 6 | AD3 — MCU address/data bit 3 |
| Pin 7 | AD4 — MCU address/data bit 4 |
| Pin 8 | AD5 — MCU address/data bit 5 |
| Pin 9 | AD6 — MCU address/data bit 6 |
| Pin 10 | AD7 — MCU address/data bit 7 |
| Pin 11 | A8 — Address bit 8 |
| Pin 12 | A9 — Address bit 9 |
| Pin 13 | A10 — Address bit 10 |
| Pin 14 | A11 — Address bit 11 |
| Pin 15 | A12 — Address bit 12 |
| Pin 16 | A13 — Address bit 13 |
| Pin 17 | A14 — Address bit 14 |
| Pin 18 | A15 — Address bit 15 |
| Pin 19 | A16 — Address bit 16 (Flash upper bank) |
| Pin 20 | A17 — Address bit 17 (Flash upper bank) |
| Pin 21 | VCC — 3.3V power supply |
| Pin 22 | GND — Ground |
| Pin 23 | CNTL0 — Control input 0 (PSEN/RD select) |
| Pin 24 | CNTL1 — Control input 1 (WR/select) |
| Pin 25 | CNTL2 — Control input 2 (ALE/latch enable) |
| Pin 26 | CSI — Chip Select In (CPLD) |
| Pin 27 | CSO0 — Chip Select Out 0 (CPLD) |
| Pin 28 | CSO1 — Chip Select Out 1 (CPLD) |
| Pin 29 | CSO2 — Chip Select Out 2 (CPLD) |
| Pin 30 | PCO0 — Peripheral I/O 0 (CPLD macrocell) |
| Pin 31 | PCO1 — Peripheral I/O 1 (CPLD macrocell) |
| Pin 32 | PCO2 — Peripheral I/O 2 (CPLD macrocell) |
| Pin 33 | PCO3 — Peripheral I/O 3 (CPLD macrocell) |
| Pin 34 | PCO4 — Peripheral I/O 4 (CPLD macrocell) |
| Pin 35 | PCO5 — Peripheral I/O 5 (CPLD macrocell) |
| Pin 36 | PCO6 — Peripheral I/O 6 (CPLD macrocell) |
| Pin 37 | PCO7 — Peripheral I/O 7 (CPLD macrocell) |
| Pin 38 | TCK — JTAG Test Clock (ISP) |
| Pin 39 | TMS — JTAG Test Mode Select (ISP) |
| Pin 40 | TDI — JTAG Test Data In (ISP) |
| Pin 41 | TDO — JTAG Test Data Out (ISP) |
| Pin 42 | TSTAT — Test Status / Ready output |
| Pin 43 | RESET — Global Reset input |
| Pin 44 | VSTBY — Standby supply for SRAM retention |
| Pin 45 | VCC — 3.3V power supply |
| Pin 46 | GND — Ground |
| Pin 47 | NC — Not connected |
| Pin 48 | NC — Not connected |
| Pin 49 | NC — Not connected |
| Pin 50 | NC — Not connected |
| Pin 51 | NC — Not connected |
| Pin 52 | NC — Not connected |
Typical Applications
PSD834F2V-20MI is suitable for 6 applications: Industrial 8-bit MCU System Expansion, Point-of-Sale (POS) Terminal Controllers, Smart Meter and Energy Monitoring, Automotive Body and Comfort Controllers, UPS and Power-Conversion Front-End, Legacy 8051/PIC System Modernization.
Industrial 8-bit MCU System Expansion
The PSD834F2V-20MI's 2 Mbit primary Flash plus 64 Kbit SRAM gives 8051-class MCUs an upgrade path beyond their internal code/data memory limits. Its 200 ns access time pairs well with 8051 cores running at 25 MHz or slower with zero wait-states, and the integrated CPLD replaces external 74HC address-latch and chip-select decode logic. Per the STMicroelectronics datasheet, the parallel 8-bit interface multiplexes directly onto the MCU bus, eliminating a discrete address latch. The single 3.3V supply simplifies the power tree versus legacy 5V Flash plus 12V Vpp designs.
Recommended
Point-of-Sale (POS) Terminal Controllers
POS terminals require non-volatile storage for firmware, transaction logs, and configuration parameters. The PSD834F2V-20MI's dual-bank Flash (2 Mbit primary for application code, 256 Kbit secondary for transaction records) supports concurrent read-while-erase, ideal for systems that must log transactions without interrupting service. Per the datasheet, the JTAG ISP interface enables field firmware updates without removing the terminal from service, and the 52-PQFP package keeps the BOM compact for slim-line POS form factors.
Recommended
Smart Meter and Energy Monitoring
Smart electricity and water meters store calibration tables, rolling consumption logs, and tamper flags in non-volatile memory that must survive power loss. The PSD834F2V-20MI's 256 Kbit secondary Flash provides 32K bytes of parameter storage ideal for time-of-use tariff tables and tamper-event logs, while the 64 Kbit SRAM holds metering variables between ADC samples. Per the datasheet, the -40 C to +85 C industrial temperature range supports outdoor meter enclosures, and the 52-PQFP's robust leads survive vibration in field installations.
Recommended
Automotive Body and Comfort Controllers
Body controllers manage windows, mirrors, lighting, and climate with 8-bit MCUs that need extended Flash for multi-feature firmware plus EEPROM emulation for trim-level configuration. The PSD834F2V-20MI's 256 Kbit secondary Flash serves as wear-leveled EEPROM for storing seat-position memory, mirror presets, and dealer configuration - tasks previously requiring an external I2C EEPROM. Per the STMicroelectronics datasheet, the parallel interface avoids the latency overhead of I2C/SPI EEPROMs during boot-time configuration recall.
Recommended
UPS and Power-Conversion Front-End
Uninterruptible power supplies and solar inverters need fast firmware updates in the field plus reliable storage of calibration constants. The PSD834F2V-20MI's JTAG-ISP enables field-upgradeable inverter control firmware without opening the enclosure, while the 64 Kbit SRAM buffers ADC samples between control-loop iterations. According to the datasheet, the 200 ns access time is well-suited to control-loop MCUs running at 20 MHz, and the integrated CPLD can generate the timing signals for the IGBT gate-driver stage.
Recommended
Legacy 8051/PIC System Modernization
Designers maintaining installed bases of 8051, 68HC11, or early PIC systems can use the PSD834F2V-20MI to consolidate the existing Flash, SRAM, and glue logic into a single footprint-compatible device. Per the STMicroelectronics datasheet, the parallel interface and chip-select decoding match the original MCU bus timing, so legacy firmware runs unchanged. This reduces PCB complexity, improves EMC by shortening bus traces, and extends product life without an expensive redesign.
Recommended
Recommended Products Summary
Engineering reference data for PSD834F2V-20MI — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PSD834F2V-15M | PSD834F2V-20JI | PSD834F2V-15J | PSD834F2V-12M | PSD834F2-70M |
|---|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Package | 52-PQFP (10x10) | 52-PQFP (10x10) - same | 52-PLCC | 52-PLCC | 52-PQFP (10x10) - same | 52-PQFP (10x10) - same |
| Memory Size | 2 Mbit Flash + 256 Kbit + 64 Kbit SRAM | 2 Mbit Flash + 256 Kbit + 64 Kbit SRAM - same | 2 Mbit Flash + 256 Kbit + 64 Kbit SRAM - same | 2 Mbit Flash + 256 Kbit + 64 Kbit SRAM - same | 2 Mbit Flash + 256 Kbit + 64 Kbit SRAM - same | 2 Mbit Flash + 256 Kbit + 64 Kbit SRAM - same |
| Access Time | 200 ns | 150 ns (25% faster) | 200 ns - same | 150 ns (25% faster) | 120 ns (40% faster) | 70 ns (65% faster) |
| Supply Voltage | 3.0 V to 3.6 V | 3.0 V to 3.6 V - same | 3.0 V to 3.6 V - same | 3.0 V to 3.6 V - same | 3.0 V to 3.6 V - same | 3.0 V to 3.6 V - same |
| Interface | Parallel 8-bit MCU | Parallel 8-bit MCU - same | Parallel 8-bit MCU - same | Parallel 8-bit MCU - same | Parallel 8-bit MCU - same | Parallel 8-bit MCU - same |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C - same | -40 C to +85 C - same | -40 C to +85 C - same | -40 C to +85 C - same | -40 C to +85 C - same |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND | NRND |
Key Differentiators
- Higher-density memory than 8051 discrete solutions (vs Discrete 8051 + 29F040 + 62256 + 74HC573 design)
- Faster access than -20 grade for higher MCU clocks (vs PSD834F2V-15M)
- Industrial temperature range for harsh environments (vs Commercial-grade 28C-series parallel Flash)
Design Notes
Route the MCU address/data bus to the PSD834F2V-20MI's AD[0:7] pins with matched trace lengths (within 50 mils) to preserve bus timing at 200 ns access. Per the datasheet, the parallel bus is the timing-critical interface - isolate it from switching power traces with a ground guard ring. Decouple VCC pins with 0.1 uF ceramic capacitors placed within 3 mm of each VCC pin, plus a 10 uF bulk tantalum near the package.
Do not connect the VSTBY pin (pin 44) to VCC without verifying the standby-current specification - if the SRAM retention feature is unused, tie VSTBY to GND to disable it and save quiescent current. Per the datasheet, leaving VSTBY floating can cause unpredictable boot behavior. Also ensure JTAG pins (TCK/TMS/TDI/TDO) are not left floating during normal operation; pull them to defined logic levels via 10 kohm resistors to prevent accidental ISP-mode entry.
When using the integrated CPLD for chip-select generation, verify that the CNTL[0:2] inputs are properly connected to the MCU's PSEN, RD, and ALE signals - mis-wiring these inputs is the most common cause of 'PSD not responding' debugging issues. Per the STMicroelectronics datasheet, the CNTL inputs determine the MCU interface mode (multiplexed vs separate address/data). Place a 0.1 uF decoupling cap adjacent to the RESET pin to suppress noise-induced spurious resets.
Compliance Information
RoHS/REACH compliance status not explicitly stated in the verified web data; designers should request the latest material declaration from STMicroelectronics. Not AEC-Q100 qualified (industrial grade, not automotive grade).
