1 特性

• 完全集成 模拟前端，用于脉冲血氧仪 应用范围：
  • 灵活的脉冲排序和
    定时控制
• 发射：
  • 集成发光二极管 (LED) 驱动器
    （H 桥、推挽）
  • 动态范围：95dB
  • LED 电流：
    • 可编程至具有 8 位电流分辨率的 50mA 电流
  • 低功耗：
    • 100µA + 平均 LED 电流
  • 可编程 LED 接通时间
  • 独立的 LED2 和 LED1 电流基准
• 具有高动态范围的接收通道：
  • 13 个无噪声位
  • 低功率：在使用 3.3V 电源供电时小于 670µA
  • 集成数字环境估算和删减
  • 灵活的接收采样时间
  • 具有可编程 LED 设置的灵活转阻放大器
• 集成式故障诊断：
  • 光电二极管和 LED 开路与
    短路检测
  • 线缆接通和断开检测
• 电源：
  • Rx = 2.0V 至 3.6V
  • Tx = 3.0V 至 5.25V
• 封装：紧凑型超薄四方扁平无引线 (VQFN)-40 (6mm x 6mm)
• 额定温度范围： 0°C 至 70°C

2 应用

• 低成本 医疗脉冲血氧仪应用
• 光学心率监视器 (HRM)
• 工业光测量应用

3 说明

AFE4400 是一款非常适合于脉冲血氧仪应用的完全集成模拟前端 (AFE)。 此器件包含一个具有集成模数转换器 (ADC) 的低噪声接收器通道、一个 LED 发射部件和针对传感器以及 LED 故障检测的诊断功能。 此器件是一款可配置定时控制器。 这个灵活性使得用户能够完全控制器件定时特性。 为了简化计时要求并为 AFE4400 提供一个低抖动时钟，还集成了一个由外部晶振供频的振荡器。 此器件使用一个 SPI™ 接口与外部微控制器或主机处理器通信。

此器件是一个单体、紧凑型 VQFN-40 封装 (6mm x 6mm) 内的完整 AFE 解决方案，其额定工作温度范围为 0°C 至 70°C。

1. 如需了解所有可用封装，请见数据表末尾的可订购产品附录。

4 修订历史记录

Changes from G Revision (July 2014) to H Revision

• Changed HBM value from ±4000 to ±1000 in Handling Ratings table Go
• Changed CDM value from ±1500 to ±250 in Handling Ratings table Go

Changes from F Revision (October 2013) to G Revision

• 已将格式更改为符合最新的数据表标准；已添加全新章节，并已删除现有章节Go
• Changed 发射 特性着重号的子着重号Go
• Changed 集成故障诊断 特性着重号的第二子着重号Go
• Added AFE4403 row to Family and Ordering Information tableGo
• Changed title of Device Family Options tableGo
• Changed INM to INN in VCM description of Pin Descriptions tableGo
• Changed Absolute Maximum Ratings table: changed first five rows and added TXP, TXN pins rowGo
• Deleted Typical value (> 1.3) for Logic high input voltage Go
• Deleted Typical value (> -0.4) for Logic low input voltage Go
• Changed SPISTE, SPISIMO, and SPISOMI pin names in Figure 1Go
• Changed SPISTE and SPISIMO pin names in Figure 2Go
• Added second and third paragraphs to the Receiver Front-End section Go
• Changed seventh paragraph in Receiver Front-End sectionGo
• Changed title of Ambient Cancellation Scheme and Second Stage Gain Block sectionGo
• Changed descriptions of LED2, ambient, and LED1 convert phases in Receiver Control Signals sectionGo
• Changed description of Receiver Timing section Go
• Changed Example column values for rows t₂, t₄, t₅, t₁₁, t₁₃, t₁₅, t₁₇, t₁₉, t₂₂, t₂₄, t₂₆, and t₂₈ in Table 2Go
• Added footnote 2 to Table 2Go
• Added footnote 2 to Figure 42Go
• Added footnote 2 to Figure 43Go
• Changed the ADC Operation and Averaging Module section: grammatical edits and changed the second sentence of the second paragraphGo
• Changed INN pin name in Figure 53Go
• Changed INM to INN in Table 5Go
• Changed SPISTE, SPISIMO, SPISOMI, and SCLK pin names in Figure 58Go
• Added Application and Implementation sectionGo

Changes from E Revision (October 2013) to F Revision

• Changed footnote 1 in Recommended Operating Conditions tableGo
• Changed LED_DRV_SUP parameter in Recommended Operating Conditions tableGo
• Changed TXM to TXN in V_LED footnote of Recommended Operating Conditions tableGo
• Changed Transmitter, Voltage on TXP (or TXN) pin parameter in Electrical Characteristics tableGo
• Changed Figure 54 (changed TXP and TXN pin names, deleted LED 1 and LED 2 pin names)Go

Changes from D Revision (May 2013) to E Revision

• Deleted 芯片图Go
• Changed 第 3 特性着重号的第 1 个子着重号Go
• Changed 电源特性着重号的最后一个子着重号Go
• 已更新首页图形Go
• Changed Tx Power Supply column in Family and Ordering Information tableGo
• Changed TX_REF description in Pin Descriptions tableGo
• Changed TX_CTRL_SUP value in Recommended Operating Conditions tableGo
• Changed conditions for Electrical Characteristics tableGo
• Changed Performance, PRF parameter minimum specification in Electrical Characteristics tableGo
• Deleted Performance, I_{IN_FS} parameter from Electrical Characteristics tableGo
• Changed Performance, CMRR parameter in Electrical Characteristics tableGo
• Changed Performance (Full-Signal Chain), Total integrated noise current and N_FB parameter test conditions in Electrical Characteristics tableGo
• Changed Receiver Functional Block Level Specification, Total integrated noise current parameter test conditions in Electrical Characteristics tableGo
• Changed Ambient Cancellation Stage, Gain parameter in Electrical Characteristics tableGo
• Added Low-Pass Filter, Filter settling time parameter to Electrical Characteristics tableGo
• Changed Diagnostics, Duration of diagnostics state machine parameter unit value in Electrical Characteristics tableGo
• Changed External Clock, Maximum allowable external clock jitter parameter in Electrical Characteristics tableGo
• Updated Figure 8 to Figure 10Go
• Updated Figure 11 to Figure 16Go
• Updated Figure 17 to Figure 19Go
• Updated Figure 31 and Figure 32Go
• Updated functional block diagramGo
• Updated Figure 34Go
• Changed second sentence in second paragraph of Receiver Front-End sectionGo
• Changed third paragraph of Receiver Front-End sectionGo
• Changed second paragraph of Ambient Cancellation Scheme sectionGo
• Added last paragraph and Table 1 to Ambient Cancellation Scheme sectionGo
• Updated Figure 37Go
• Updated Figure 39Go
• Added footnote 1 to Table 2Go
• Changed example column in Table 2Go
• Added last sentence to third column of row t₁₃ in Table 2Go
• Deleted last sentence from third column of row t₁₄ in Table 2Go
• Changed corresponding register address name in row t₂₁ of Table 2Go
• Updated Figure 42Go
• Updated Figure 43Go
• Updated Figure 44Go
• Changed entire Transmit SectionGo
• Changed second paragraph of the ADC Operation and Averaging Module sectionGo
• Updated Figure 49Go
• Changed Operation section title and first sentenceGo
• Changed last sentence of the Operation With Averaging section Go
• Updated Figure 52Go
• Changed last paragraph of Diagnostics Module sectionGo
• Added first and last sentence to Writing Data sectionGo
• Changed second to last sentence in Writing Data sectionGo
• Added first and last sentence to Reading Data sectionGo
• Changed second to last sentence in Reading Data sectionGo
• Added Multiple Data Reads and Writes sectionGo
• Added last sentence to the AFE SPI Interface Design Considerations sectionGo
• Added Register Control column to Table 6Go
• Changed name of ADCRSTSTCT0 register (address 15h) in Table 6Go
• Changed bit D10 in CONTROL2 row of Table 6Go
• Changed CONTROL0 paragraph descriptionGo
• Added note to bit D2 description of CONTROL0 registerGo
• Corrected bit names in ADCRSTSTCT0 registerGo
• Changed PRPCOUNT[15:0] (bits D[15:0]) description of PRPCOUNT registerGo
• Changed note within CLKALMPIN[2:0] (bits D[11:9]) description of CONTROL1 registerGo
• Changed second and third columns of Table 7Go
• Changed 001 and 011 bit settings for the STG2GAIN[2:0] bits (bits D[10:8]) in the TIA_AMB_GAIN registerGo
• Changed bit D10 of the CONTROL2 registerGo