MAX1121EGK+TD - 250Msps 8-Bit ADC, LVDS, QFN-68 | Maxim
料号： MAX1121EGK+TD ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $28.5 | $28.50 |
| 10 | $26.1 | $261.00 |
| 100 | $22.4 | $2,240.00 |
| 500 | $19.25 | $9,625.00 |
| 1,000 | $17.1 | $17,100.00 |
MAX1121EGK+TD 概述
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.
直接替换替代料： MAX1121EGK+TD ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： MAX1121EGK+TD （相同外形与封装尺寸） ——差异在于 Mounting Type, Output Interface, Package.
快速对比工具——选择替代料号进行并排对比：
MAX1121EGK+D
✅ 直接替换📋 参考替代料（不在目录中）
MAX1122EGK+TD
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
AD9484BCPZ-250
✅ 直接替换📋 参考替代料（不在目录中）
MAX1121EGK+TD 最大额定值与电气特性
| 分辨率 | 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) |
| 基准电压 | Internal (on-chip) |
| 封装 | 68-pin QFN-EP (10 mm x 10 mm, 0.9 mm) |
| Package Code | G6800-4 (HVQCCN) |
| 工作温度范围 | -40 C to +85 C (Industrial) |
| Lead-Free / RoHS Status | RoHS Compliant |
| 安装类型 | Surface Mount (Tape & Reel) |
MAX1121EGK+TD 引脚配置
| 引脚 1 | AVDD — Analog supply (1.8V) |
| 引脚 2 | REF_OUT — Internal reference output (bypass cap required) |
| 引脚 3 | REF_IN — Reference input (tie to REF_OUT) |
| 引脚 4 | REF_GND — Reference ground |
| 引脚 5 | GND — Analog ground |
| 引脚 6 | INP — Differential analog input P |
| 引脚 7 | INN — Differential analog input N |
| 引脚 8 | IN_GND — Analog input common-mode return |
| 引脚 9 | AVDD — Analog supply (1.8V) |
| 引脚 10 | CLKP — Differential clock input P |
| 引脚 11 | CLKN — Differential clock input N |
| 引脚 12 | AVDD — Analog supply (1.8V) |
| 引脚 13 | GND — Analog ground |
| 引脚 14 | PD_N — Power-down (active-low) |
| 引脚 15 | RESET_N — Reset (active-low) |
| 引脚 16 | MODE — Output mode control |
| 引脚 17 | AVDD — Analog supply (1.8V) |
| 引脚 18 | GND — Analog ground |
| 引脚 19 | OVDD — Output supply (1.8V LVDS) |
| 引脚 20 | GND — Digital ground |
| 引脚 21 | ORP — LVDS out-of-range clock P |
| 引脚 22 | ORN — LVDS out-of-range clock N |
| 引脚 23 | OVDD — Output supply (1.8V LVDS) |
| 引脚 24 | GND — Digital ground |
| 引脚 25 | OUT7P — LVDS data output 7 P |
| 引脚 26 | OUT7N — LVDS data output 7 N |
| 引脚 27 | OVDD — Output supply (1.8V LVDS) |
| 引脚 28 | GND — Digital ground |
| 引脚 29 | OUT6P — LVDS data output 6 P |
| 引脚 30 | OUT6N — LVDS data output 6 N |
| 引脚 31 | OVDD — Output supply (1.8V LVDS) |
| 引脚 32 | GND — Digital ground |
| 引脚 33 | OUT5P — LVDS data output 5 P |
| 引脚 34 | OUT5N — LVDS data output 5 N |
| 引脚 35 | OVDD — Output supply (1.8V LVDS) |
| 引脚 36 | GND — Digital ground |
| 引脚 37 | OUT4P — LVDS data output 4 P |
| 引脚 38 | OUT4N — LVDS data output 4 N |
| 引脚 39 | OVDD — Output supply (1.8V LVDS) |
| 引脚 40 | GND — Digital ground |
| 引脚 41 | OUT3P — LVDS data output 3 P |
| 引脚 42 | OUT3N — LVDS data output 3 N |
| 引脚 43 | OVDD — Output supply (1.8V LVDS) |
| 引脚 44 | GND — Digital ground |
| 引脚 45 | OUT2P — LVDS data output 2 P |
| 引脚 46 | OUT2N — LVDS data output 2 N |
| 引脚 47 | OVDD — Output supply (1.8V LVDS) |
| 引脚 48 | GND — Digital ground |
| 引脚 49 | OUT1P — LVDS data output 1 P |
| 引脚 50 | OUT1N — LVDS data output 1 N |
| 引脚 51 | OVDD — Output supply (1.8V LVDS) |
| 引脚 52 | GND — Digital ground |
| 引脚 53 | OUT0P — LVDS data output 0 P |
| 引脚 54 | OUT0N — LVDS data output 0 N |
| 引脚 55 | OVDD — Output supply (1.8V LVDS) |
| 引脚 56 | GND — Digital ground |
| 引脚 57 | DCLK_P — LVDS DDR clock output P |
| 引脚 58 | DCLK_N — LVDS DDR clock output N |
| 引脚 59 | OVDD — Output supply (1.8V LVDS) |
| 引脚 60 | GND — Digital ground |
| 引脚 61 | D_OUT_P — LVDS serial data output P (optional) |
| 引脚 62 | D_OUT_N — LVDS serial data output N (optional) |
| 引脚 63 | GND — Digital ground |
| 引脚 64 | NC — Not connected (per datasheet) |
| 引脚 65 | NC — Not connected (per datasheet) |
| 引脚 66 | TEST — Test mode pin (tie to GND in normal operation) |
| 引脚 67 | GND — Analog ground |
| 引脚 68 | AVDD — Analog supply (1.8V) |
典型应用
MAX1121EGK+TD 适用于 6 应用s: 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.
推荐
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.
推荐
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.
推荐
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.
推荐
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.
推荐
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.
推荐
推荐产品汇总
工程参考数据： MAX1121EGK+TD ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | 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 |
关键差异点
- Maxim's dedicated wideband IF-sampling 8-bit ADC family （对比 AD9484BCPZ-250)
- LVDS output standard on a 1.8V supply （对比 AD9484BCPZ-250)
- On-chip reference and exposed-pad package （对比 MAX1121EGK+D (tray variant))
设计说明
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.
合规信息
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.
