16 ビットの AFE88101 および 14 ビットの AFE78101 (AFEx8101) は、センサ・トランスミッタ・アプリケーション向けに設計された、高集積度、高精度、超低消費電力の電圧出力 D/A コンバータ (DAC) です。
AFEx8101 デバイスには、4mA から 20mA の 2 線式 (ループ電源) センサ・トランスミッタを設計するために必要な構成要素のほとんどが含まれています。これらのデバイスには、高精度な DAC に加えて、10ppm/℃の電圧リファレンスと診断用 A/D コンバータ (ADC) が内蔵されています。内在的および機能安全上の問題に対応するには、外部の電圧電流変換と、電源のレギュレーションが必要です。
内蔵の診断 ADC は複数の内部ノードに多重化されており、自動的な自己ヘルス・チェックを可能にしています。このチェックにより、内蔵のバイアス源や電源レギュレータ、電圧リファレンス、DAC 出力、ダイ温度に関するエラーや故障を検出でき、さらにオプションとして外部電圧源の問題も検出できます。診断用 ADC、CRC フレーム・エラー・チェック、あるいはウィンドウ付きのウォッチドッグ・タイマから、いずれかの障害が検出された場合、本デバイスは (オプションとして) 割り込みの発行、あるいは標準の NAMUR 出力値またはユーザー指定のカスタム値に応じたフェイルセーフ状態への遷移、またはその両方を開始できます。
これらのデバイスは最小 1.71V の電源で動作し、最大静止電流は 210μA です。本デバイスの温度範囲は -40℃~ +125℃で規定されていますが、-55℃~+125℃で機能することが可能です。
部品番号 | 分解能 | パッケージ(1) |
---|---|---|
AFE78101 | 14 ビット | RRU (UQFN、24) 4.00mm×4.00mm |
AFE88101 | 16 ビット |
DATE | REVISION | NOTES |
---|---|---|
December 2022 | * | Initial release. |
PIN | TYPE(1) | DESCRIPTION | |
---|---|---|---|
NAME | NO. | ||
AIN0 | 15 | AI | ADC input voltage. The input range is 0 V to VREF if PVDD = VDD, or 0 V to 2 × VREF if PVDD > 2.7 V. |
ALARM | 24 | DO | Alarm notification. Open drain. When alarm condition is asserted, this pin is held to logic low; otherwise, this pin is in a high-impedance state (Hi-Z). |
CLK_OUT | 11 | DO | Clock output. This pin can be configured as a clock output for the 1.2288‑MHz internal clock. |
CS | 10 | DI | SPI chip-select. Data bits are clocked into the serial shift register when CS is logic low. When CS is logic high, SDO is in a high-impedance state and data on SDI are ignored. Do not leave any digital input pins floating. |
GND | 14 | P | Digital and analog ground. Ground reference point for all circuitry on the device. |
GND | 21, 22 | P | Digital and analog ground. |
IOVDD | 12 | P | Interface supply. Supply voltage for digital input and output circuitry. This voltage sets the logical thresholds for the digital interfaces. |
NC | 3, 23 | – | No connection. Leave floating. |
POL_SEL/AIN1 | 16 | DI/AI | ADC input voltage if SPECIAL_CFG.AIN1_ENB bit is set to 1. The input range is 0 V to VREF if PVDD = VDD, or 0 V to 2 × VREF if PVDD > 2.7 V. Otherwise, this pin acts as ALMV_POL, which sets the polarity of the VOUT alarm voltage. |
PVDD | 17 | P | Power supply for the internal low-dropout regulator (LDO), ADC input, and VOUT DAC output. When 2.7 V to 5.5 V is provided, the internal LDO turns on and drives VDD internally. When 1.71 V to 1.89 V is provided, the internal LDO is disabled. |
REF_EN | 5 | DI | Internal VREF enable input. A logic high on this pin enables the internal VREF and the VREFIO pin outputs 1.25 V. A logic low on this pin disables the internal VREF and the external 1.25-V reference is required at the VREFIO pin. |
REF_GND | 20 | P | GND reference for VREFIO pin. |
RESET | 6 | DI | Reset. Logic low on this pin places the device into power-down mode and resets the device. Logic high returns the device to normal operation. Do not leave any digital input pins floating. |
SCLK | 7 | DI | SPI serial clock. Data can be transferred at rates up to 12.5 MHz. SCLK is a Schmitt-trigger logic input. Connect to GND or logic low if not used. Do not leave any digital input pins floating. |
SCLR | 4 | DI | DAC clear input pin in SPI mode. A logic high on this pin forces the DAC output into a CLEAR state. Connect to GND in UBM. Do not leave any digital input pins floating. |
SDI | 8 | DI | SPI data input. Data are clocked into the 24‑bit input shift register on the falling edge of the serial clock input. SDI is a Schmitt-Trigger logic input. Do not leave any digital input pins floating. |
SDO | 9 | DO | SPI data output. Data are output on the rising edge of SCLK when CS is logic low. Interrupt request (IRQ) pin in the UART break mode (UBM). The output is in a Hi-Z state at power up and must be enabled in the CONFIG register. |
UARTIN | 1 | DI | UART data input. Connect to IOVDD or logic high if not used. Do not leave any digital input pins floating. |
UARTOUT | 2 | DO | UART data output. This pin can be configured to function as the IRQ pin in SPI only mode. |
VDD | 13 | P/AO | Power supply. When 2.7 V to 5.5 V is provided on PVDD pin, the internal LDO drives VDD internally. Connect a 1‑μF to 10‑μF capacitor to this pin. When 1.71 V to 1.89 V is provided on the PVDD pin, an external power supply must be provided on this pin. |
VOUT | 18 | AO | DAC output voltage. |
VREFIO | 19 | AI/AO | When the internal VREF is enabled by REF_EN pin, this pin outputs the internal VREF voltage. In this case, a load capacitance of 70-nF to 130-nF is required for stability. When disabled, this pin is the external 1.25‑V reference input. |
MIN | MAX | UNIT | |||
---|---|---|---|---|---|
Voltage | PVDD, IOVDD to GND | –0.3 | 5.5 | V | |
VDD to GND | –0.3 | 1.98 | V | ||
AIN0, POL_SEL/AIN1, VOUT to GND | –0.3 | PVDD + 0.3 | V | ||
Digital Input/Output to GND | –0.3 | IOVDD + 0.3 | V | ||
VREFIO to GND | –0.3 | VDD + 0.3 | V | ||
REF_GND to GND | –0.3 | 0.3 | V | ||
Input current | Current into any pin | –10 | 10 | mA | |
TJ | Junction temperature | –55 | 150 | °C | |
Tstg | Storage temperature | –65 | 150 |