K4A8G085WB - 8Gb B-die DDR4 SDRAM 1Gx8 | Samsung
MPN: K4A8G085WB ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.48 | $6.48 |
| 10 | $6.15 | $61.50 |
| 100 | $5.8 | $580.00 |
| 500 | $5.5 | $2,750.00 |
| 1,000 | $5.2 | $5,200.00 |
Drop-in alternatives for K4A8G085WB — 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:
K4A8G085WB-BCRC
✅ Drop-In✓ In Stock
$6.8 / Unit
View Datasheet →K4A8G085WB-BCPB
✅ Drop-In✓ In Stock
$3.28 / Unit
View Datasheet →K4A8G085WB-BIRC
✅ Drop-In✓ In Stock
$4.15 / Unit
View Datasheet →K4A8G085WB-BITD
✅ Drop-In✓ In Stock
$3.8 / Unit
View Datasheet →K4A8G085WB-BCTD
✅ Drop-In✓ In Stock
$7.5 / Unit
View Datasheet →K4A8G085WC-BCTD
✅ Drop-In✓ In Stock
$50.85 / Unit
View Datasheet →K4A8G085WC-BIWE
✅ Drop-In✓ In Stock
$6.29 / Unit
View Datasheet →K4A8G085WB Maximum Ratings & Electrical Characteristics
| Memory Type | DDR4 SDRAM (B-die) |
| Density | 8 Gbit |
| Organization | 1G x 8 |
| Supply Voltage | 1.2 V |
| Package | 78-pin FBGA |
| Mounting Type | Surface Mount |
| Operating Mode | DLL Enabled mode (per datasheet) |
| Speed Grade Suffixes | -BCRC, -BIRC, -BCTD, -BCPB (per family naming) |
K4A8G085WB [data_needed: package dimensions] Pin Configuration Guide
Complete pinout information for K4A8G085WB ([data_needed: package dimensions] package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
![[data_needed: package dimensions] package pinout diagram for K4A8G085WB](/assets/package-diagrams/default.svg?v=1788069619)
No detailed pinout data available for K4A8G085WB.
Refer to the datasheet for full pin configuration.
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
K4A8G085WB is suitable for 6 applications: Server and Data Center DIMMs, Networking and Telecom Equipment, Industrial Embedded Computing, High-Performance Computing Accelerators, Desktop PC and Consumer Motherboards, Automotive and Rugged Infotainment Memory.
Server and Data Center DIMMs
Server main memory is the primary application for 8Gb B-die DDR4 SDRAM. The K4A8G085WB's 8Gbit density in a x8 organization is the classic building block for registered and load-reduced DIMMs, where 9 or 18 x8 chips create single-rank or dual-rank 8GB/16GB modules. The 1.2V DDR4 interface with fly-by termination topology keeps per-rail power low at high capacities, and the FBGA-78 package supports the dense stacking required on standard 288-pin RDIMM and LRDIMM form factors. The B-die silicon is widely qualified across server platforms; designers must configure the memory controller (RCD) for the device's speed grade and bank-group timing, and program SPD data to match the installed grade.
Recommended
Networking and Telecom Equipment
Switches, routers, and baseband cards use solder-down DDR4 as deep-packet-buffer and control-plane memory. The K4A8G085WB fits these designs because its x8 organization matches network processor and FPGA memory controllers that expose 8-, 16-, or 32-bit DDR4 interfaces, allowing 1-4 chips per controller channel. The 1.2V supply simplifies power-tree design in telecom chassis where VDDQ rails are already provisioned, and DLL-enabled operation delivers stable timing across the industrial card temperature range when the -BIxx industrial grades are selected. Layout should follow short, length-matched fly-by address/command routing with on-die termination enabled to maintain signal integrity on high-layer-count boards.
Recommended
Industrial Embedded Computing
Industrial PCs, machine-vision controllers, and edge AI gateways require DRAM capacity and bandwidth with long-term availability. The K4A8G085WB in industrial grade (-BIRC, -BITD) supports these platforms, soldered directly beside x86 or ARM SoCs with integrated DDR4 controllers. The 8Gb density allows 4GB-8GB system memory with only 4-8 components, reducing BOM line count versus 4Gb alternatives, and the FBGA-78 footprint reflows on standard SMT lines. Designers should select the industrial temperature suffix, provide the 1.2V VDD and 0.6V VTT rails with proper decoupling, and validate controller timing across temperature, since DRAM refresh and AC timing parameters must hold over the -40C to +85C (or wider) industrial range.
Recommended
High-Performance Computing Accelerators
GPGPU accelerator cards, FPGA compute boards, and HPC modules use solder-down DDR4 as local scratchpad and workspace memory alongside HBM or as the main system memory pool. The K4A8G085WB's high 8Gb per-chip density lets accelerator designers reach 16-32GB local memory with compact x8 channel groupings, and the DDR4 interface achieves multi-Gbps transfer rates per pin in higher speed grades, delivering the streaming bandwidth large matrix workloads demand. XAIPART cross-reference data notes this Samsung DDR4 portfolio is intended for high-bandwidth, low-operating-voltage computing platforms. Multi-rank designs should use balanced loading per chip-select and verify signal-integrity margins at the target data rate with IBIS models.
Recommended
Desktop PC and Consumer Motherboards
Consumer desktop platforms use unbuffered DIMMs built from 8Gb x8 DDR4 chips; the K4A8G085WB B-die has become well known in the enthusiast community for its overclocking characteristics, though it is specified per Samsung's JEDEC DDR4 datasheet in standard DLL-enabled operation. A 16GB unbuffered UDIMM uses sixteen 8Gb x8 devices in single- or dual-rank topology. The 1.2V rail is provided directly from the motherboard VDDQ regulator, and the FBGA-78 packages reflow onto the module PCB in one pass. Consumer builds typically select commercial grades (-BCxx); OEMs must program SPD EEPROM data with the installed device's timings so the BIOS trains the memory controller correctly.
Recommended
Automotive and Rugged Infotainment Memory
Automotive infotainment, telematics, and ADAS domain controllers solder down DDR4 for navigation-map buffers and camera-frame stores. The K4A8G085WB family, using the industrial/wide-temperature -BI grades suited to automotive cabin and near-engine environments after board-level qualification, provides the 4-8GB working memory these SoCs require with a proven 1.2V DDR4 interface. Solder-down FBGA mounting withstands vibration better than socketed modules, a key advantage in vehicles. Designs should implement full DDR4 controller training, temperature-compensated refresh, and conformal-coated layout for harsh environments. Note this standard-grade part is not AEC-Q100 qualified by default; confirm the specific grade's automotive qualification status with Samsung for safety-relevant systems.
Recommended
Recommended Products Summary
Engineering reference data for K4A8G085WB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | K4A8G085WB-BCRC | K4A8G085WB-BIRC | K4A8G085WC-BCTD | K4A8G085WC-BIWE |
|---|---|---|---|---|---|
| Package | 78-pin FBGA | 78-pin FBGA - same | 78-pin FBGA - same | 78-pin FBGA - same | 78-pin FBGA - same |
| Brand | Samsung Electronics | Samsung Electronics | Samsung Electronics | Samsung Electronics | Samsung Electronics |
| Density | 8 Gbit | 8 Gbit | 8 Gbit | 8 Gbit | 8 Gbit |
| Organization | 1G x 8 | 1G x 8 | 1G x 8 | 1G x 8 | 1G x 8 |
| Supply Voltage | 1.2 V | 1.2 V | 1.2 V | 1.2 V | 1.2 V |
| Temperature Grade | Depends on suffix | Commercial | Industrial | Commercial | Industrial wide-temp |
| Die Revision | B-die | B-die | B-die | C-die (next rev) | C-die (next rev) |
| Price (qty 1, as of 2026-09-04) | $6.48 (family, BIRC grade) | [DATA_NEEDED] | $6.4758 (LCSC) | [DATA_NEEDED] | [DATA_NEEDED] |
Key Differentiators
- 8Gb B-die density halves component count vs 4Gb parts (vs K4A4G085WD-BCRC)
- Industrial grade availability with in-stock distribution (vs K4A8G085WB-BCRC)
- Same footprint as next-revision C-die parts eases migration (vs K4A8G085WC-BCTD)
Design Notes
The 78-pin FBGA fanout is the hardest part of a DDR4 solder-down layout. Use via-in-pad (filled and capped) or dog-bone escape routing on the outer ball rows, and plan layer stackup so each DQ byte lane (8 DQ + DQS/DM) has a dedicated inner-layer pair. Keep address/command on fly-by topology with per-DIMM-style series termination. For x8 parts, DQS is a single differential pair (UDQS/UDQS# plus LDQS/LDQS# for x16 - here x8 uses one pair), so length-match DQS to its DQ byte within tight skew budgets.
Provide three rails: 1.2V VDD, 1.2V VDDQ, and 0.6V VTT termination rail. Estimated: each x8 DDR4 chip can draw roughly 200-400 mA from VDDQ at speed depending on grade and activity, so size VTT regulators for the total termination current across all chips (typically up to ~0.5A per chip transient). Place bulk capacitance near each device group and high-frequency ceramic caps inside the FBGA ball field. VTT requires a low-impedance split plane - do not share it with other noisy loads.
The most frequent error is ordering by truncated MPN. The suffix encodes speed grade and temperature (-BCRC vs -BIRC vs -BCTD differ in data rate and/or operating range), and C-die parts (K4A8G085WC) may carry timing differences versus B-die per public documentation. Always verify the full suffix, cross-check controller timing at the target data rate, and program SPD/strap settings to the actual device. Substituting a commercial grade into an industrial design without thermal validation risks field failures.
Compliance Information
Compliance status not stated in provided web data; consult Samsung product pages or request compliance certificates from Samsung Semiconductor.
