ADA4945-1ACPZ - Low-Noise FDA ADC Driver, 3-10V | Analog Devices
料号： ADA4945-1ACPZ ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $6.18 | $6.18 |
| 10 | $5.45 | $54.50 |
| 100 | $4.22 | $422.00 |
| 500 | $3.45 | $1,725.00 |
| 1,000 | $2.93 | $2,930.00 |
ADA4945-1ACPZ 概述
A fully differential amplifier (FDA) is an op-amp derivative with differential inputs and differential outputs. FDAs sit in the signal-chain hierarchy between operational amplifiers and differential amplifiers, providing common-mode rejection, suppressing even-order harmonics, and converting single-ended signals into balanced differential signals for modern differential-input ADCs. The ADA4945-1 belongs to the broader analog IC category, specifically under amplifier ICs and the special-purpose ADC-driver sub-family.
Key specifications include 0.1 µV/°C offset drift, low DC offset, an output common-mode (VOCM) pin for setting the ADC input common-mode voltage, adjustable output common-mode, output limiting for ADC overdrive protection, and excellent dynamic performance. The high-voltage SiGe complementary bipolar process enables operation up to 10 V — higher than many competing FDAs — providing headroom for ADCs with wider input ranges.
Technically, the SiGe dielectrically-isolated process delivers low distortion and low input voltage noise simultaneously, while the selectable power-mode pin optimizes current draw for either maximum bandwidth or low-power applications. The differential output stage provides two closely balanced outputs in response to either differential or single-ended inputs, simplifying the interface to differential ADCs such as the AD9680, AD9268, and AD9656.
Typical applications include high-speed ADC drivers, medical imaging front ends, communications receivers, IF and baseband signal chains, and industrial instrumentation. The low offset drift maintains DC accuracy over temperature, while rail-to-rail outputs maximize dynamic range in low-voltage systems.
When designing with the ADA4945-1, set VOCM to match the ADC input common-mode voltage, select the appropriate power mode for the bandwidth/power trade-off, and follow the datasheet PCB layout guidelines to minimize parasitic capacitance and preserve signal integrity at high frequencies.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and practical design notes not found on the manufacturer datasheet alone.
直接替换替代料： ADA4945-1ACPZ ——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： ADA4945-1ACPZ （相同外形与封装尺寸） ——差异在于 Package, Output Type, Supply Voltage Range, Operating Temperature, Operating Temperature Range.
快速对比工具——选择替代料号进行并排对比：
ADA4945-1ACPZ-R7
✅ 直接替换📋 参考替代料（不在目录中）
ADA4945-1ACPZ-RL7
✅ 直接替换✓ 有现货
$3.1 / 个
查看数据手册 →ADA4945-1ACPZ-R2
✅ 直接替换📋 参考替代料（不在目录中）
ADA4940-1ACPZ
✅ 直接替换✓ 有现货
$3.92 / 个
查看数据手册 →ADA4940-1ACPZ-RL7
✅ 直接替换✓ 有现货
$4.1 / 个
查看数据手册 →ADA4941-1ARZ
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$2.88 / 个
查看数据手册 →ADA4945-1ACPZ 最大额定值与电气特性
| Product Type | Fully Differential Amplifier (FDA) / ADC Driver |
| Number of Channels | 1 |
| Supply Voltage Range | 3 V to 10 V |
| Input Voltage Noise (full power mode) | 1.8 nV/√Hz |
| Input Offset Voltage Drift | 0.1 µV/°C |
| 输出类型 | Differential, rail-to-rail |
| Power Modes | 2 selectable (full power / low power) |
| Output Common-Mode Control | Yes (VOCM pin) |
| Output Limiting | Yes |
| 工作温度范围 | -40 °C to +125 °C |
| 封装 | 16-LFCSP (3 mm × 3 mm) with exposed pad |
| 安装类型 | Surface Mount |
| Process Technology | SiGe complementary bipolar, dielectrically isolated |
| RoHS 状态 | Compliant |
| Lead-Free | Yes |
ADA4945-1ACPZ 引脚配置
| 引脚 1 | VOUT+ — Differential output, positive |
| 引脚 2 | VOUT- — Differential output, negative |
| 引脚 3 | VS+ — Positive supply |
| 引脚 4 | FB — Feedback for output stage |
| 引脚 5 | VOCM — Output common-mode voltage input |
| 引脚 6 | NC — Not connected (per datasheet) |
| 引脚 7 | PD — Power-down / power-mode select |
| 引脚 8 | NC — Not connected (per datasheet) |
| 引脚 9 | IN+ — Differential input, positive |
| 引脚 10 | IN- — Differential input, negative |
| 引脚 11 | VS- — Negative supply |
| 引脚 12 | NC — Not connected (per datasheet) |
| 引脚 13 | VLIMIT — Output voltage limit threshold |
| 引脚 14 | NC — Not connected (per datasheet) |
| 引脚 15 | NC — Not connected (per datasheet) |
| 引脚 16 | NC — Not connected (per datasheet) |
典型应用
ADA4945-1ACPZ 适用于 6 应用s: High-Speed ADC Driver, Medical Imaging Front End, Communications Receiver IF Strip, Test and Measurement Instrumentation, Industrial Data Acquisition, Radar and Lidar Signal Chain.
High-Speed ADC Driver
The ADA4945-1 is purpose-built as a fully differential ADC driver for high-speed data-acquisition systems. With 1.8 nV/√Hz input voltage noise in full-power mode, 0.1 µV/°C offset drift, and an adjustable output common-mode (VOCM) pin, it cleanly translates single-ended or differential input signals into the differential domain required by modern ADCs such as the AD9680 (14-bit, 1 GSPS) and AD9268 (16-bit, 125 MSPS). The output-limiting feature protects the ADC input from overdrive during fault conditions, improving system robustness. Place the ADA4945-1 within 1 cm of the ADC inputs, use 0402 surface-mount feedback and gain-setting resistors, and follow the ADA4945-1CP-EBZ evaluation board layout. For very-high-resolution ADCs above 16 bits, the low-power mode may not provide sufficient bandwidth.
推荐
Medical Imaging Front End
In ultrasound, CT, and MRI receivers, the ADA4945-1 drives high-speed ADCs that digitize low-amplitude signals from piezoelectric or coil sensors. Its 1.8 nV/√Hz input noise preserves the signal-to-noise ratio required for diagnostic imaging, while the 0.1 µV/°C offset drift maintains DC calibration across the 0-70 °C imaging-suite temperature range. The two selectable power modes let portable ultrasound carts trade bandwidth for battery life between scans. Output common-mode control allows direct coupling to the ADC's internal bias network without AC-coupling capacitors that would distort low-frequency tissue harmonics. Pair with the AD9671 ultrasound AFE for complete front-end integration.
推荐
Communications Receiver IF Strip
The ADA4945-1 serves as an IF baseband driver in software-defined radios and wireless receivers where it converts the differential outputs of mixers and IF filters into the differential inputs of high-speed ADC sampling stages. Rail-to-rail differential outputs maximize dynamic range at the 3-10 V supply range, while the high PSRR rejects noise from upstream switching regulators in the radio chain. The selectable power modes allow receivers to lower current draw in standby without changing the BOM. For direct-conversion receivers, the low offset drift of 0.1 µV/°C prevents DC wander from corrupting the baseband. Pair with the AD9361 or AD9371 integrated transceivers for complete SDR platforms.
推荐
Test and Measurement Instrumentation
Oscilloscopes, spectrum analyzers, and data-acquisition modules use the ADA4945-1 as the input buffer/ADC driver for high-channel-count digitizer boards. The 16-LFCSP (3 × 3 mm) footprint allows dense multi-channel layouts, and the low noise floor preserves the 14-16 bit ENOB of precision ADCs across the full input bandwidth. The output limiting pin protects expensive converter ICs during overvoltage input events from the DUT, increasing instrument reliability in production test environments. The selectable power modes let engineers tune power dissipation against sample rate for benchtop versus rack-mount form factors.
推荐
Industrial Data Acquisition
Multi-channel industrial DAQ boards digitize signals from sensors in factory automation, process control, and condition-monitoring systems. The ADA4945-1's wide 3-10 V supply range is compatible with industrial 24 V bus systems (regulated down locally), and its rail-to-rail outputs maximize dynamic range when digitizing bipolar transducer signals such as strain gauges and load cells. Low offset drift maintains calibration across the extended -40 °C to +125 °C industrial temperature range, and the differential outputs reject common-mode noise from motors and switching power supplies in the factory floor environment.
推荐
Radar and Lidar Signal Chain
In automotive radar baseband receivers and lidar analog front ends, the ADA4945-1 drives high-speed ADCs sampling I/Q baseband signals at tens to hundreds of MSPS. Its low distortion preserves the spurious-free dynamic range needed for object detection and classification, while the selectable power modes allow systems to reduce current draw between radar chirps. The output common-mode control matches the ADC's input common-mode without AC-coupling, preserving the DC bias needed for narrowband baseband channels. Pair with the ADAR7251 automotive radar AFE for complete radar signal chains.
推荐
推荐产品汇总
工程参考数据： ADA4945-1ACPZ ——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 | ADA4945-1ACPZ-R7 | ADA4945-1ACPZ-RL7 | ADA4945-1ACPZ-R2 | ADA4940-1ACPZ | ADA4941-1ARZ |
|---|---|---|---|---|---|---|
| Package | 16-LFCSP (3x3) | 16-LFCSP (3x3) - same | 16-LFCSP (3x3) - same | 16-LFCSP (3x3) - same | 16-LFCSP (3x3) - same | 16-LFCSP (3x3) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Supply Voltage Range | 3 V to 10 V | 3 V to 10 V | 3 V to 10 V | 3 V to 10 V | 3 V to 6 V | 2.7 V to 5.5 V |
| Input Voltage Noise (full power) | 1.8 nV/√Hz | 1.8 nV/√Hz | 1.8 nV/√Hz | 1.8 nV/√Hz | 3.9 nV/√Hz | 3.5 nV/√Hz |
| Offset Drift | 0.1 µV/°C | 0.1 µV/°C | 0.1 µV/°C | 0.1 µV/°C | 0.7 µV/°C | 1.0 µV/°C |
| Selectable Power Modes | Yes (2 modes) | Yes | Yes | Yes | No | No |
| Output Limiting | Yes (VLIMIT pin) | Yes | Yes | Yes | No | No |
| Output Common-Mode Control | Yes (VOCM pin) | Yes | Yes | Yes | Yes | Yes |
| Pricing (qty 1, USD, as of 2026-10-06) | $6.18 | $6.18 | $6.18 | $6.45 | $4.50 | $3.85 |
关键差异点
- Selectable power modes for noise-versus-power optimization （对比 ADA4940-1ACPZ)
- Output limiting for ADC overdrive protection （对比 ADA4940-1ACPZ and ADA4941-1ARZ)
- 10 V supply operation enabled by SiGe high-voltage process （对比 ADA4940-1ACPZ (5 V max) and ADA4941-1ARZ (5.5 V max))
设计说明
Use the ADA4945-1CP-EBZ evaluation board layout as a starting reference. Place 0402 feedback and gain-setting resistors within 2 mm of the inverting and non-inverting input pins to minimize parasitic capacitance. Route VOCM as a wide, guarded trace directly from the ADC's VCM reference output. Use 0805 bypass capacitors on each supply pin (VS+ and VS-) with a 0.1 µF X7R ceramic in parallel with a 10 µF tantalum or polymer capacitor. Solder the exposed pad (EP) to a continuous ground plane with at least 8 thermal vias for low thermal resistance (θJA ≈ 50 °C/W).
Do not leave the VOCM pin floating - it must be driven to the ADC's required input common-mode voltage (typically 0.5 × AVDD or mid-rail). Floating VOCM causes the differential output common-mode to drift and reduces ADC dynamic range. Do not exceed the VLIMIT pin's absolute maximum rating when programming output limiting. When using the low-power mode, derate the bandwidth specification by approximately 30% versus full-power mode and verify SNR with the target ADC. Do not assume the ADA4945-1 and ADA4940-1 are interchangeable - an ADI EngineerZone thread dated 2026-08 confirms pinout and supply differences require schematic review.
Maintain differential trace impedance of 100 Ω (±10%) from the ADA4945-1 outputs to the ADC inputs. Match trace lengths to within 0.5 mm (about 7 ps) to preserve the differential balance that the FDA is designed to deliver. Use a solid ground reference plane directly beneath the differential traces, with no trace crossovers. At sample rates above 100 MSPS, consider adding a small (2-10 pF) common-mode capacitor across each differential pair at the ADC input to filter common-mode noise without degrading the differential signal.
合规信息
RoHS compliant per ADI product page and Arrow.com listing. Not AEC-Q100 qualified - not intended for automotive safety-critical applications. Lead-free (Pb-free) reflow-compatible per JEDEC J-STD-020.
