LTC2257IUJ-14 - 14-bit, 40Msps Ultralow Power 1.8V ADC | Analog Devices
MPN: LTC2257IUJ-14 ✓ Hoạt độngLTC2257IUJ-14 Tóm tắt
What is a pipelined ADC? A pipelined analog-to-digital converter is a high-speed ADC design that processes analog input samples through multiple cascaded low-resolution flash stages, achieving sample rates from tens to hundreds of Msps while maintaining 12- to 16-bit resolution. Within the broader ADC taxonomy, it sits between flash ADCs (fastest, lowest resolution) and sigma-delta ADCs (slowest, highest resolution), making it the dominant architecture for communications infrastructure, IF digitisation, and high-speed instrumentation.
Key features of the LTC2257IUJ-14 include ±1 LSB INL (typical), ±0.3 LSB DNL (typical), no missing codes over temperature, and 1.13 LSB RMS transition noise. The digital outputs are configurable as full-rate CMOS, double-data-rate CMOS, or double-data-rate LVDS. Integrated functions include an optional clock duty-cycle stabilizer, shutdown and nap modes for power savings, and a serial SPI port for configuration.
The device is part of a pin-compatible family that includes 12-bit and 14-bit versions at 25/40/65 Msps (LTC2256-14, LTC2257-14, LTC2258-14), enabling system designers to scale performance without layout changes and the same architecture down to lower power budgets.
Typical applications include communications infrastructure (cellular basestation IF digitisation, microwave links), high-speed imaging, portable test and measurement, and ultrasonics. The 1.8V core supply and 49 mW dissipation allow battery-powered designs without sacrificing dynamic range.
When designing with this ADC, prioritise the analog input front-end (driver amplifier, antialias filter), supply decoupling, and PCB layout symmetry around the differential analog inputs. Use the exposed pad for thermal and ground-plane stitching.
This page synthesises distributor pricing, drop-in pin-compatible alternatives, and design notes beyond what is found on the manufacturer product page, giving engineers a single source for procurement and substitution analysis.
Bộ thay thế dễ dàng lắp đặt cho LTC2257IUJ-14 — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với LTC2257IUJ-14 (cùng hình factor và footprint) — khác nhau ở Package, Sample Rate, Configuration Interface, Power-Saving Modes, Resolution.
LTC2257CUJ-14
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LTC2256IUJ-14
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
LTC2258IUJ-14
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LTC2259IUJ-14
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
LTC2260IUJ-14
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LTC2261IUJ-14
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LTC2257IUJ-14 Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 14 bit |
| Sample Rate | 40 Msps |
| Architecture | Pipelined |
| Number of Inputs | 1 |
| Input Type | Differential (single-ended capable) |
| Analog Supply Voltage | 1.7 V to 1.9 V (1.8 V nominal) |
| Digital Output Supply | 1.2 V to 1.8 V |
| INL (typical) | ±1 LSB |
| DNL (typical) | ±0.3 LSB |
| Transition Noise | 1.13 LSB RMS |
| Missing Codes | None over temperature |
| Output Interface | CMOS / DDR CMOS / DDR LVDS (selectable) |
| Hộp | 40-QFN (UJ) 6x6 mm with exposed pad |
| Kiểu lắp đặt | Surface Mount |
| Nhiệt độ hoạt động | -40C to +85C (I grade) |
| Configuration Interface | SPI serial port |
| Power-Saving Modes | Shutdown, Nap modes |
| Clock Duty-Cycle Stabilizer | Optional, on-chip |
| Reference Type | External or internal (per variant) |
| Trạng thái RoHS | Compliant (#PBF suffix) |
Cấu hình chân LTC2257IUJ-14
| Chân 1 | GND — Ground (must connect to exposed pad) |
| Chân 2 | VDD — 1.8V analog supply |
| Chân 3 | GND — Ground |
| Chân 4 | VDD — 1.8V analog supply |
| Chân 5 | GND — Ground |
| Chân 6 | AIN+ — Differential analog input positive |
| Chân 7 | AIN- — Differential analog input negative |
| Chân 8 | GND — Ground |
| Chân 9 | VREF — Voltage reference bypass/decoupling |
| Chân 10 | SENSE — Reference configuration (internal/external) |
| Chân 11 | GND — Ground |
| Chân 12 | OVDD — Digital output supply (1.2V to 1.8V) |
| Chân 13 | GND — Ground |
| Chân 14 | CLK+ — Encode clock input positive |
| Chân 15 | CLK- — Encode clock input negative (or tied to CLK+ for single-ended) |
| Chân 16 | GND — Ground |
| Chân 17 | D0 — Data output bit 0 (LSB) |
| Chân 18 | D1 — Data output bit 1 |
| Chân 19 | D2 — Data output bit 2 |
| Chân 20 | D3 — Data output bit 3 |
| Chân 21 | D4 — Data output bit 4 |
| Chân 22 | D5 — Data output bit 5 |
| Chân 23 | D6 — Data output bit 6 |
| Chân 24 | D7 — Data output bit 7 |
| Chân 25 | D8 — Data output bit 8 |
| Chân 26 | D9 — Data output bit 9 |
| Chân 27 | D10 — Data output bit 10 |
| Chân 28 | D11 — Data output bit 11 |
| Chân 29 | D12 — Data output bit 12 |
| Chân 30 | D13 — Data output bit 13 (MSB) |
| Chân 31 | DNC — Do not connect (per datasheet) |
| Chân 32 | DNC — Do not connect (per datasheet) |
| Chân 33 | DNC — Do not connect (per datasheet) |
| Chân 34 | OGND — Output driver ground |
| Chân 35 | OVDD — Output driver supply |
| Chân 36 | SDO — SPI serial data output |
| Chân 37 | SDI — SPI serial data input |
| Chân 38 | SCK — SPI serial clock |
| Chân 39 | CS — SPI chip select (active low) |
| Chân 40 | SHDN — Shutdown (active high) |
| Chân PAD | Exposed Pad — Thermal/ground pad - must be soldered to PCB ground |
Ứng dụng tiêu biểu
LTC2257IUJ-14 phù hợp cho 6 Áp dụngs: Cellular Basestation IF Digitisation, Portable Test and Measurement Instrumentation, Ultrasound Imaging Front-End, High-Speed Industrial Imaging, Software-Defined Radio Receiver, Radar and Lidar Signal Processing.
Cellular Basestation IF Digitisation
The LTC2257IUJ-14's 14-bit resolution at 40 Msps makes it well suited for digitising intermediate-frequency (IF) signals in cellular base-station receivers, where signal bandwidths of 5-15 MHz are common and dynamic range is critical. Its 1.13 LSB RMS transition noise preserves small-signal fidelity and SFDR, which is critical for distinguishing adjacent-channel blockers and maintaining EVM in the demodulated signal. The 1.8V analog supply and 49 mW dissipation ease thermal budgets in densely populated radio units, while the configurable CMOS/DDRLVDS outputs interface directly to modern FPGAs without level translators. The pin-compatible LTC2258-14 (65 Msps) or LTC2259-14 (80 Msps) can be substituted later for wider bandwidth systems without PCB rework.
Được đề xuất
Portable Test and Measurement Instrumentation
Battery-powered oscilloscopes, spectrum analysers, and data-acquisition modules benefit from the LTC2257IUJ-14's 1.8V single-supply operation and 49 mW typical power dissipation at 40 Msps, extending battery runtime versus 3V/5V ADCs. The 14-bit resolution and ±1 LSB INL provide measurement accuracy suitable for general signal capture and low-speed protocol analysis. The SPI configuration port lets a host MCU adjust output mode, clock-duty-cycle stabiliser, and power-down modes to trade noise versus runtime dynamically, while the 40-QFN (6x6 mm) small footprint leaves board space for input protection and channel multiplexing. Shutdown and nap modes cut quiescent current for triggered or burst-mode acquisitions.
Được đề xuất
Ultrasound Imaging Front-End
The LTC2257IUJ-14 is well suited to digitising low-frequency ultrasound receive channels after the TGC stage, where 14-bit dynamic range and 40 Msps sample rate are sufficient for transducers up to ~15 MHz. Its low transition noise (1.13 LSB RMS) helps preserve subtle echo contrast in B-mode and Doppler processing, while the low power dissipation eases thermal design in multi-channel probe heads where many ADCs operate near each other. The configurable LVDS outputs allow long trace runs back to an FPGA-based beamformer without EMI issues, and the SPI port enables per-channel gain calibration to compensate for transducer variability. Pin-compatible family members allow a common PCB across 8-, 16-, and 32-channel probe variants.
Được đề xuất
High-Speed Industrial Imaging
Line-scan and area-scan machine-vision cameras use the LTC2257IUJ-14 to digitise CCD/CIS analog outputs where 14-bit dynamic range captures subtle gray-scale variations. At 40 Msps, the part easily handles pixel clocks up to 40 MHz, supporting 4K line-scan imagers and high-resolution area sensors at moderate frame rates. The 1.8V analog supply simplifies power-rail design in industrial 24V-bus systems after a downstream buck converter, and the small 40-QFN footprint leaves board area for serializer and FPGA logic. The differential analog input rejects common-mode noise from nearby motor drives, and the configurable DDR LVDS output minimises FPGA pin count for high-speed data transfer.
Được đề xuất
Software-Defined Radio Receiver
Software-defined radio (SDR) platforms digitise wide-bandwidth IF or RF signals directly, where the LTC2257IUJ-14's 14-bit resolution at 40 Msps enables capture of signals up to ~18 MHz in a single Nyquist zone. Its ±1 LSB INL and 1.13 LSB RMS transition noise preserve signal fidelity for digital demodulation, and the DDR LVDS output mode supports direct connection to high-speed FPGAs for real-time DSP. The optional clock-duty-cycle stabiliser relaxes the requirement on the source encoder clock quality, important when using fractional-N synthesizers. Designers can scale up to the pin-compatible LTC2261-14 (125 Msps) for direct-RF sampling at HF/VHF without PCB changes.
Được đề xuất
Radar and Lidar Signal Processing
Automotive and industrial radar/lidar front-ends digitise IF or baseband return signals, where the LTC2257IUJ-14's 14-bit resolution captures fine range and amplitude resolution while its 49 mW dissipation helps keep multi-channel PCB thermal rise manageable. At 40 Msps, the part captures Doppler-shifted returns up to ~18 MHz footprint, suitable for short-range automotive radar IF stages and short-pulse lidar receivers. The pin-compatible LTC2258-14 (65 Msps) or LTC2259-14 (80 Msps) can be used for wider-bandwidth FMCW chirps, all without PCB rework. The DDR LVDS output streams high-speed digital data to an FPGA-based FFT accelerator for range-Doppler map generation.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho LTC2257IUJ-14 — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | LTC2257CUJ-14 | LTC2256IUJ-14 | LTC2258IUJ-14 | LTC2259IUJ-14 |
|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 40-QFN (UJ) 6x6 mm | 40-QFN (UJ) 6x6 mm - same | 40-QFN (UJ) 6x6 mm - same | 40-QFN (UJ) 6x6 mm - same | 40-QFN (UJ) 6x6 mm - same |
| Resolution | 14 bit | 14 bit | 14 bit | 14 bit | 14 bit |
| Sample Rate | 40 Msps | 40 Msps | 25 Msps | 65 Msps | 80 Msps |
| Temperature Grade | Industrial -40C to +85C | Commercial 0C to +70C | Industrial -40C to +85C | Industrial -40C to +85C | Industrial -40C to +85C |
| Analog Supply | 1.8V | 1.8V | 1.8V | 1.8V | 1.8V |
| Output Interface | CMOS / DDR CMOS / DDR LVDS | CMOS / DDR CMOS / DDR LVDS | CMOS / DDR CMOS / DDR LVDS | CMOS / DDR CMOS / DDR LVDS | CMOS / DDR CMOS / DDR LVDS |
| Pin Compatibility | Reference | Drop-in (same package, same pinout) | Drop-in (same package, same pinout) | Drop-in (same package, same pinout) | Drop-in (same package, same pinout) |
Bảo phân biệt quan trọng
- Pin-compatible family enables single PCB for 25/40/65/80/105/125 Msps (vsLTC2256IUJ-14, LTC2258IUJ-14, LTC2259IUJ-14)
- Ultralow power at 40 Msps (vsAD9248 (legacy 14-bit, 40 Msps))
- Selectable CMOS/DDR CMOS/DDR LVDS outputs with separate OVDD rail (vsLTC2246HLX (older 14-bit ADC, single CMOS output))
Ghi chú thiết kế
Solder the exposed thermal pad of the 40-QFN (UJ) package to a continuous ground plane using multiple thermal vias for heat spreading. Use a four-layer PCB with the second layer as a solid ground plane directly under the ADC; place analog input traces on the top layer with controlled 50-character impedance and keep them short and symmetric for the differential pair. Per the Analog Devices datasheet, supply decoupling requires 0.1uF and 10uF ceramic capacitors placed as close as possible to each VDD pin, plus a ferrite bead on the analog supply if it shares a regulator with digital circuitry.
Drive the analog input with a differential amplifier such as the AD8138 or a transformer-coupled front-end to achieve the rated SFDR and SNR. The encode clock should be a low-jitter, differential source (LVPECL or LVDS), and the optional on-chip clock-duty-cycle stabiliser can be enabled via SPI to correct 50% duty-cycle distortion up to 100 MHz. Per the AnalogDatas datasheet, keep the encode clock traces away from the analog input traces and surround them with ground pours to minimise crosstalk. Match the trace lengths of the differential CLK+/CLK- pair to within 5 ps for best jitter performance.
Do not leave the OVDD pin unconnected - it powers the digital output drivers and must be supplied between 1.2V and 1.8V regardless of output mode. Do not drive the analog input beyond the absolute maximum rating (VDD + 0.3V) or allow DC common-mode voltage above the supply, as this can damage the input ESD structures. Per the AnalogDevices datasheet, the SHDN pin must be driven low for normal operation; leaving it floating enables shutdown mode. Ensure the SPI CS pin is pulled high (inactive) during power-up to avoid spurious writes to the configuration register.
Thông tin tuân thủ
RoHS compliance indicated by #PBF suffix per DigiKey listing. Not AEC-Q100 qualified - this part targets industrial/commercial applications. Reach status confirmed compliant per Analog Devices product page.
