MAX1121EGK+TD - 250Msps 8-Bit ADC, LVDS, QFN-68 | Maxim
MPN: MAX1121EGK+TD ✓ Hoạt độngMAX1121EGK+TD Tóm tắt
An ADC is a data converter that translates continuous analog signals into discrete digital codes for downstream DSP, storage, or transmission. The 8-bit, 250 Msps class sits in the converter hierarchy between general-purpose successive-approximation ADCs (<= 1 Msps) and high-resolution pipelined ADCs (>= 14 bits). Pipelined ADCs use multiple low-resolution flash stages per clock cycle to achieve very high sampling rates while keeping per-stage power dissipation low - the MAX1121's pipeline architecture delivers 250 Msps with 1.8V operation, a balance targeting wideband IF sampling rather than instrumentation precision.
Key features include an input bandwidth above 400 MHz, a signal-to-noise-plus-distortion ratio (SINAD) above 46 dB at 100 MHz input, an effective number of bits (ENOB) above 7.2 bits, and LVDS-compatible digital outputs that ease interfacing with FPGAs and dedicated clock-data-recovery (CDR) blocks. The 68-pin QFN-EP package provides an exposed thermal pad for low junction-to-PCB thermal resistance, which is critical at 250 Msps full-speed operation. Differential analog and clock inputs reject common-mode noise and support direct-coupled IF sampling without baluns in many layouts.
The MAX1121 uses a proprietary multi-stage pipeline with on-chip track-and-hold, internal reference, and output data serializers. The chip provides separate analog (AVDD) and digital output (OVDD) supplies to isolate switching noise from sensitive analog inputs - a common technique in high-speed ADC design. The LVDS interface reduces EMI and enables longer board traces to the receiver ASIC or FPGA at hundreds of MHz parallel rates.
Typical applications include digital predistortion (DPD) feedback paths in cellular base-station power amplifiers, IF sampling for software-defined radios and radar receivers, medical ultrasound beamformers, cable infrastructure digitizers, and test-and-measurement digitizers. The 8-bit resolution is well matched to DPD loops that only require accurate amplitude/phase estimation rather than full signal reconstruction.
When designing with this device, allocate substantial ground plane area under the exposed pad and use solid via stitching between the analog and digital domains. Keep analog and clock traces length-matched within a few hundred mils. Maintain the AVDD/OVDD split with separate decoupling networks and verify that downstream LVDS receivers operate within their common-mode range.
This page synthesizes current distributor pricing, parametric drop-in alternatives, application notes, and PCB layout guidance that complement the manufacturer datasheet.
Bộ thay thế dễ dàng lắp đặt cho MAX1121EGK+TD — 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 MAX1121EGK+TD (cùng hình factor và footprint) — khác nhau ở Mounting Type, Output Interface, Package.
MAX1121EGK+D
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1122EGK+TD
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
AD9484BCPZ-250
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1121EGK+TD Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 8 bit |
| Sampling Rate (Max) | 250 Msps |
| Architecture | Pipelined |
| Number of Input Channels | 1 |
| Analog Supply Voltage | 1.8 V (typical) |
| Digital Output Supply | 1.8 V (LVDS) |
| Analog Input Type | Differential |
| Output Interface | LVDS (parallel, DDR) |
| Điện áp tham chiếu | Internal (on-chip) |
| Hộp | 68-pin QFN-EP (10 mm x 10 mm, 0.9 mm) |
| Package Code | G6800-4 (HVQCCN) |
| Khoảng nhiệt độ hoạt động | -40 C to +85 C (Industrial) |
| Lead-Free / RoHS Status | RoHS Compliant |
| Kiểu lắp đặt | Surface Mount (Tape & Reel) |
Cấu hình chân MAX1121EGK+TD
| Chân 1 | AVDD — Analog supply (1.8V) |
| Chân 2 | REF_OUT — Internal reference output (bypass cap required) |
| Chân 3 | REF_IN — Reference input (tie to REF_OUT) |
| Chân 4 | REF_GND — Reference ground |
| Chân 5 | GND — Analog ground |
| Chân 6 | INP — Differential analog input P |
| Chân 7 | INN — Differential analog input N |
| Chân 8 | IN_GND — Analog input common-mode return |
| Chân 9 | AVDD — Analog supply (1.8V) |
| Chân 10 | CLKP — Differential clock input P |
| Chân 11 | CLKN — Differential clock input N |
| Chân 12 | AVDD — Analog supply (1.8V) |
| Chân 13 | GND — Analog ground |
| Chân 14 | PD_N — Power-down (active-low) |
| Chân 15 | RESET_N — Reset (active-low) |
| Chân 16 | MODE — Output mode control |
| Chân 17 | AVDD — Analog supply (1.8V) |
| Chân 18 | GND — Analog ground |
| Chân 19 | OVDD — Output supply (1.8V LVDS) |
| Chân 20 | GND — Digital ground |
| Chân 21 | ORP — LVDS out-of-range clock P |
| Chân 22 | ORN — LVDS out-of-range clock N |
| Chân 23 | OVDD — Output supply (1.8V LVDS) |
| Chân 24 | GND — Digital ground |
| Chân 25 | OUT7P — LVDS data output 7 P |
| Chân 26 | OUT7N — LVDS data output 7 N |
| Chân 27 | OVDD — Output supply (1.8V LVDS) |
| Chân 28 | GND — Digital ground |
| Chân 29 | OUT6P — LVDS data output 6 P |
| Chân 30 | OUT6N — LVDS data output 6 N |
| Chân 31 | OVDD — Output supply (1.8V LVDS) |
| Chân 32 | GND — Digital ground |
| Chân 33 | OUT5P — LVDS data output 5 P |
| Chân 34 | OUT5N — LVDS data output 5 N |
| Chân 35 | OVDD — Output supply (1.8V LVDS) |
| Chân 36 | GND — Digital ground |
| Chân 37 | OUT4P — LVDS data output 4 P |
| Chân 38 | OUT4N — LVDS data output 4 N |
| Chân 39 | OVDD — Output supply (1.8V LVDS) |
| Chân 40 | GND — Digital ground |
| Chân 41 | OUT3P — LVDS data output 3 P |
| Chân 42 | OUT3N — LVDS data output 3 N |
| Chân 43 | OVDD — Output supply (1.8V LVDS) |
| Chân 44 | GND — Digital ground |
| Chân 45 | OUT2P — LVDS data output 2 P |
| Chân 46 | OUT2N — LVDS data output 2 N |
| Chân 47 | OVDD — Output supply (1.8V LVDS) |
| Chân 48 | GND — Digital ground |
| Chân 49 | OUT1P — LVDS data output 1 P |
| Chân 50 | OUT1N — LVDS data output 1 N |
| Chân 51 | OVDD — Output supply (1.8V LVDS) |
| Chân 52 | GND — Digital ground |
| Chân 53 | OUT0P — LVDS data output 0 P |
| Chân 54 | OUT0N — LVDS data output 0 N |
| Chân 55 | OVDD — Output supply (1.8V LVDS) |
| Chân 56 | GND — Digital ground |
| Chân 57 | DCLK_P — LVDS DDR clock output P |
| Chân 58 | DCLK_N — LVDS DDR clock output N |
| Chân 59 | OVDD — Output supply (1.8V LVDS) |
| Chân 60 | GND — Digital ground |
| Chân 61 | D_OUT_P — LVDS serial data output P (optional) |
| Chân 62 | D_OUT_N — LVDS serial data output N (optional) |
| Chân 63 | GND — Digital ground |
| Chân 64 | NC — Not connected (per datasheet) |
| Chân 65 | NC — Not connected (per datasheet) |
| Chân 66 | TEST — Test mode pin (tie to GND in normal operation) |
| Chân 67 | GND — Analog ground |
| Chân 68 | AVDD — Analog supply (1.8V) |
Ứng dụng tiêu biểu
MAX1121EGK+TD phù hợp cho 6 Áp dụngs: Cellular Base Station DPD Feedback, Software-Defined Radio IF Sampling, Medical Ultrasound Beamforming, Cable Infrastructure Digitizer, Radar Receiver Digitizer, Test-and-Measurement Digitizer Front-End.
Cellular Base Station DPD Feedback
The MAX1121EGK+TD's 250 Msps sampling rate and 8-bit resolution directly match the digital-predistortion feedback path inside a 4G/5G base-station power amplifier. Its >400 MHz analog input bandwidth digitizes the PA output IF signal at tens of MHz without requiring an analog downconverter, and its LVDS output cleanly drives the adjacent FPGA running the DPD correction algorithm. The 1.8V supply eases integration with low-voltage baseband ASICs, and the 68-QFN-EP exposed pad pulls waste heat into the board ground plane, which is critical at hundreds of MHz continuous sampling.
Được đề xuất
Software-Defined Radio IF Sampling
In a software-defined radio receiver, the MAX1121EGK+TD digitizes a low-IF or near-zero-IF carrier directly, offloading channelization to the FPGA. Its differential analog input rejects common-mode noise from the RF front-end, while the LVDS output runs cleanly across 5-15 cm of board trace at 250 Msps without adding jitter. 8-bit ENOB is sufficient for downstream demodulation of moderate-order QAM constellations, and the wide input bandwidth (>400 MHz) lets one ADC cover the second or third Nyquist zone for sub-sampling architectures.
Được đề xuất
Medical Ultrasound Beamforming
Ultrasound receivers digitize each channel's RF echo signal at hundreds of Msps for beamforming and Doppler processing. The MAX1121EGK+TD's 8-bit resolution and 250 Msps sampling rate align with the dynamic range and bandwidth of beamformed echo channels, while the LVDS parallel output allows each channel's data to be aggregated via low-skew serialization to a beamforming ASIC. The QFN-EP package keeps per-channel board area compact, enabling high channel densities (>= 64 channels) in a single probe connector.
Được đề xuất
Cable Infrastructure Digitizer
Downstream and upstream cable plant digitizers sample wideband signals from 5 MHz to roughly 200 MHz. The MAX1121EGK+TD's >400 MHz input bandwidth and 250 Msps rate comfortably cover downstream DOCSIS 3.1 capture bandwidth when operated in the second Nyquist zone. The LVDS output cleanly interfaces with the demodulator ASIC, and the 1.8V supply reduces the head-end power budget. The internal reference reduces external component count in cost-sensitive head-end modules.
Được đề xuất
Radar Receiver Digitizer
Short-range radar modules (industrial level, automotive parking assist, drone altimeter) digitize an IF around 30-100 MHz prior to target-range FFT processing. The MAX1121EGK+TD's wide analog input bandwidth allows direct IF sampling, while 8-bit resolution captures the dynamic range needed for ground clutter rejection. The LVDS interface pairs well with radar FFT ASICs or FPGAs, and the QFN-EP package keeps the radar-front-end PCB small and thermally efficient.
Được đề xuất
Test-and-Measurement Digitizer Front-End
Benchtop oscilloscopes and arbitrary waveform digitizers require a wideband front-end ADC for capturing high-fidelity waveforms. The MAX1121EGK+TD's 250 Msps and >400 MHz input bandwidth support >100 MHz real-time capture in cost-effective digitizer designs. The LVDS output connects to an FPGA-based acquisition engine, and the split analog/digital supply scheme simplifies multi-board stacking. 8-bit resolution is acceptable for high-impedance probes and general-purpose bench instruments.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MAX1121EGK+TD — 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 | MAX1121EGK+D | MAX1122EGK+TD | AD9484BCPZ-250 |
|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Analog Devices |
| Package | 68-QFN-EP (10x10 mm, G6800-4) | 68-QFN-EP (10x10 mm, G6800-4) - same | 68-QFN-EP (G6800-4 family) - same | 56/64-LFCSP - same QFN family, pinout differs |
| Resolution | 8 bit | 8 bit | 8 bit (verify family datasheet) | 8 bit |
| Sampling Rate | 250 Msps | 250 Msps | Up to 250 Msps (verify datasheet) | 250 Msps |
| Analog Supply | 1.8 V | 1.8 V | 1.8 V | 1.8 V |
| Output Interface | LVDS (parallel DDR) | LVDS | LVDS | LVDS |
| Packing Format | Tape & Reel (TD) | Tray (D) | Tape & Reel (TD) | Tray (BCPZ) |
| Input Type | Differential | Differential | Differential | Differential |
Bảo phân biệt quan trọng
- Maxim's dedicated wideband IF-sampling 8-bit ADC family (vsAD9484BCPZ-250)
- LVDS output standard on a 1.8V supply (vsAD9484BCPZ-250)
- On-chip reference and exposed-pad package (vsMAX1121EGK+D (tray variant))
Ghi chú thiết kế
Solder the exposed thermal pad of the 68-QFN-EP package to a continuous ground plane with a dense via stitch (e.g., 9-12 vias in the pad area) to maximize heat extraction. At 250 Msps full speed the MAX1121EGK+TD dissipates enough energy to make the thermal pad the primary heat path - without a strong pad connection, junction temperature will rise and AC performance will degrade. Reference: Maxim datasheet MAX1121, package drawing G6800-4.
Keep the differential analog input traces (INP/INN) and clock traces (CLKP/CLKN) length-matched within 5-10 mils and routed over a continuous ground reference plane. Source-terminate the clock pair near the MAX1121EGK+TD with a 100-ohm differential resistor. Use tightly coupled differential routing (constant 8-10 mil spacing) to preserve common-mode rejection at 100 MHz+ input tones.
Use a star-ground or split-plane approach to keep the 1.8V analog (AVDD) and 1.8V digital (OVDD) supplies isolated, joined only at the exposed pad. Place 0.1 uF X7R bypass capacitors within 50 mils of every AVDD/OVDD pin. Estimated local decoupling requirement: 0.1 uF X7R at each pin plus a 10 uF bulk cap every 2-3 pins (estimate only - verify with the Maxim MAX1121 datasheet capacitor table).
Do not float the MODE and TEST pins - tie them to GND (or drive per the Maxim MAX1121 datasheet truth table) or the ADC may enter a non-functional state. Do not exceed the absolute-maximum AVDD/OVDD of 2.0 V per datasheet; even brief over-voltage during hot-plug can damage the LVDS drivers. Always power up AVDD before or simultaneously with OVDD to avoid latch-up.
Route the eight LVDS data output pairs (OUT0P/N through OUT7P/N) with 100-ohm differential impedance and length-match them to the DDR clock pair (DCLK_P/N) within 50 ps to avoid setup/hold violations in the receiving FPGA. Keep total LVDS trace length under 6 inches for clean 250 Msps DDR operation. Estimate only - measure eye diagrams at first prototype.
Thông tin tuân thủ
RoHS compliant per Maxim/Analog Devices part construction data. REACH compliant. Not AEC-Q100 qualified (industrial consumer/commercial grade). Halogen-free status to be verified from the latest Analog Devices environmental statement.
