STM32L471ZGT6 - 1MB Flash 80MHz Cortex-M4 MCU | STMicroelectronics
MPN: STM32L471ZGT6 ✓ פעילSTM32L471ZGT6 סקירה
An ultra-low-power microcontroller (MCU) is a class of microprocessor that minimizes active and standby current consumption through techniques such as voltage scaling, multiple low-power operating modes, peripheral clock gating, and integrated DC-DC converters. The STM32L4 family extends this concept with the Cortex-M4 core plus DSP instructions and a single-precision floating-point unit, enabling digital signal processing alongside efficient power management. Within the broader taxonomy, the STM32L471ZGT6 sits in the hierarchy MCU -> Arm Cortex-M microcontroller -> ultra-low-power MCU -> power management IC ecosystem.
Key features include a 1.8 V to 3.6 V supply range, batch acquisition mode for ADC, multiple low-power modes (Stop, Standby, Shutdown) drawing as little as a few hundred nanoamperes with RTC retention, a built-in 12-bit 5 Msps ADC, two DAC channels, USB 2.0 Full-Speed device/host, three I2C, three SPI, three USART plus UART, two CAN 2.0B, SDMMC, and a Crypt/AES-256 hardware accelerator. The 144-pin LQFP package supports ample GPIO for industrial control panels and sensor hubs.
The STM32L471 uses a Cortex-M4 core with FPU and DSP extensions, providing 1.25 DMIPS/MHz and a CoreMark score in the hundreds, balancing DSP capability with extreme energy efficiency. The integrated LDO(Dragon) voltage regulator and switchable DC-DC buck converter allow dynamic trade-off between quiescent current and peak performance.
Typical applications include industrial sensor nodes, wearable medical monitors, smart metering, battery-powered IoT gateways, and motor control subsystems where extended battery life and deterministic real-time response are simultaneously required. The 1 MB Flash enables on-board firmware with secure bootloaders, OTA stacks, and rich protocol libraries.
When designing, always verify the supply decoupling network (1uF + 100nF + 4.7uF bulk) per ST AN4325 reference design and consider the 32 kHz LSE crystal selection for RTC accuracy. The 144-LQFP package simplifies layout but requires thermal relief for applications pushing >70% CPU duty.
This page synthesizes verified distributor pricing, parametric drop-in alternatives, and practical low-power design notes not found in the manufacturer datasheet alone.
חלופות תחליף ישיר עבור STM32L471ZGT6 — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
וריאנטים בסדרה זו
דגמים מאותה סדרה התואמים Drop-in עם STM32L471ZGT6 (אותו גורם צורה וטביעת רגל) — שונים ב ADC, Package, SRAM, Core Architecture, Operating Temperature Range.
STM32L471RGT6
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
STM32L471VGT6
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
STM32L471QGI6
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
STM32L452RET6P
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←STM32L443RCT6
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←STM32L412RBT6P
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←STM32L471ZGT6 דירוגים מרביים ומאפיינים חשמליים
| Core | Arm Cortex-M4 with FPU and DSP |
| תדר שעון מקסימלי | 80 MHz |
| Flash Memory | 1 MB |
| SRAM | 128 KB |
| Operating Voltage Range | 1.71 V to 3.6 V |
| מארז | LQFP-144 (20 x 20 mm) |
| GPIO Count | Up to 114 |
| ADC | 3 x 12-bit, 5 Msps |
| DAC | 2 x 12-bit |
| CAN | 2 x CAN 2.0B |
| USB | USB 2.0 Full-Speed device/host |
| UART/USART | 3 x USART + 2 x UART |
| SPI | 3 x SPI |
| I2C | 3 x I2C Fast-mode Plus |
| טווח טמפרטורת פעולה | -40C to +85C |
| Cryptography | AES-256 hardware accelerator |
| סטטוס RoHS | Compliant |
תצורת פינים של STM32L471ZGT6
| פין 1 | PE02 — GPIO PE2, EXTI line 2 |
| פין 2 | PE03 — GPIO PE3, EXTI line 3 |
| פין 3 | PE04 — GPIO PE4, TRACEDATA0 |
| פין 4 | PE05 — GPIO PE5, TRACEDATA1 |
| פין 5 | PE06 — GPIO PE6, WKUP3, TIM1_BKIN2 |
| פין 6 | VBAT — Battery supply for RTC and backup registers |
| פין 7 | PC13 — GPIO PC13, anti-tamper, WKUP2, RTC_OUT |
| פין 8 | PC14 — GPIO PC14, OSC32_IN |
| פין 9 | PC15 — GPIO PC15, OSC32_OUT |
| פין 10 | VSS — Ground |
| פין 11 | VDD — Digital supply voltage |
| פין 12 | PH00 — GPIO PH0, OSC_IN |
| פין 13 | PH01 — GPIO PH1, OSC_OUT |
| פין 14 | NRST — Reset input, active low |
| פין 15 | VSSA — Analog ground |
| פין 16 | VDDA — Analog supply voltage |
| פין 17 | PA00 — GPIO PA0, WKUP1, UART4_TX, TIM2_CH1 |
| פין 18 | PA01 — GPIO PA1, UART4_RX, TIM2_CH2, ADC_IN1 |
| פין 19 | PA02 — GPIO PA2, USART2_TX, TIM2_CH3, ADC_IN2 |
| פין 20 | PA03 — GPIO PA3, USART2_RX, TIM2_CH4, ADC_IN3 |
| פין 21 | VSS — Ground |
| פין 22 | VDD — Digital supply voltage |
| פין 23 | PA04 — GPIO PA4, SPI1_NSS, USART2_CK, ADC_IN4, DAC_OUT1 |
| פין 24 | PA05 — GPIO PA5, SPI1_SCK, ADC_IN5, DAC_OUT2 |
| פין 25 | PA06 — GPIO PA6, SPI1_MISO, TIM3_CH1, ADC_IN6 |
| פין 26 | PA07 — GPIO PA7, SPI1_MOSI, TIM3_CH2, ADC_IN7 |
| פין 27 | PA08 — GPIO PA8, TIM1_CH1, USART1_CK, MCO |
| פין 28 | PA09 — GPIO PA9, TIM1_CH2, USART1_TX |
| פין 29 | PA10 — GPIO PA10, TIM1_CH3, USART1_RX |
| פין 30 | PA11 — GPIO PA11, TIM1_CH4, USB_DM |
| פין 31 | PA12 — GPIO PA12, TIM1_ETR, USB_DP |
| פין 32 | PA13 — GPIO PA13, SWDIO, JTMS |
| פין 33 | VSS — Ground |
| פין 34 | VDD — Digital supply voltage |
| פין 35 | PA14 — GPIO PA14, SWCLK, JTCK |
| פין 36 | PA15 — GPIO PA15, JTDI, TIM2_CH1 |
| פין 37 | PB00 — GPIO PB0, TIM3_CH3, ADC_IN8 |
| פין 38 | PB01 — GPIO PB1, TIM3_CH4, ADC_IN9 |
| פין 39 | PB02 — GPIO PB2, BOOT1 |
| פין 40 | PB03 — GPIO PB3, JTDO, TIM2_CH2, SPI1_SCK |
| פין 41 | PB04 — GPIO PB4, JTRST, TIM3_CH1, SPI1_MISO |
| פין 42 | PB05 — GPIO PB5, I2C1_SMBAI, TIM3_CH2, SPI1_MOSI |
| פין 43 | PB06 — GPIO PB6, I2C1_SCL, USART1_TX, TIM4_CH1 |
| פין 44 | PB07 — GPIO PB7, I2C1_SDA, USART1_RX, TIM4_CH2 |
| פין 45 | BOOT0 — Boot mode selection |
| פין 46 | PB08 — GPIO PB8, I2C1_SCL, TIM4_CH3, SDMMC1_D4 |
| פין 47 | PB09 — GPIO PB9, I2C1_SDA, TIM4_CH4, SDMMC1_D5 |
| פין 48 | VSS — Ground |
| פין 49 | VDD — Digital supply voltage |
| פין 50 | PB10 — GPIO PB10, I2C2_SCL, USART3_TX, TIM2_CH3 |
| פין 51 | PB11 — GPIO PB11, I2C2_SDA, USART3_RX, TIM2_CH4 |
| פין 52 | PB12 — GPIO PB12, SPI2_NSS, I2S2_WS, TIM1_BKIN |
| פין 53 | PB13 — GPIO PB13, SPI2_SCK, I2S2_CK, USART3_CK |
| פין 54 | PB14 — GPIO PB14, SPI2_MISO, TIM1_CH1, SDMMC1_D0 |
| פין 55 | PB15 — GPIO PB15, SPI2_MOSI, TIM1_CH2, SDMMC1_D1 |
| פין 56 | PD00 — GPIO PD0, SPI2_NSS, CAN1_RX, TIM4_CH1 |
| פין 57 | PD01 — GPIO PD1, SPI2_SCK, CAN1_TX, TIM4_CH2 |
| פין 58 | PD02 — GPIO PD2, USART3_RX, TIM3_ETR, SDMMC1_CMD |
| פין 59 | PD03 — GPIO PD3, USART2_CTS, SPI2_MISO |
| פין 60 | PD04 — GPIO PD4, USART2_RTS, SPI2_MOSI |
| פין 61 | PD05 — GPIO PD5, USART2_TX |
| פין 62 | PD06 — GPIO PD6, USART2_RX, SDMMC1_CK |
| פין 63 | PD07 — GPIO PD7, USART2_CK, SDMMC1_CMD |
| פין 64 | VSS — Ground |
| פין 65 | VDD — Digital supply voltage |
| פין 66 | PD08 — GPIO PD8, USART3_TX, SDMMC1_D0 |
| פין 67 | PD09 — GPIO PD9, USART3_RX, SDMMC1_D1 |
| פין 68 | PD10 — GPIO PD10, USART3_CK, SDMMC1_D2 |
| פין 69 | PD11 — GPIO PD11, USART3_CTS, SDMMC1_D3 |
| פין 70 | PD12 — GPIO PD12, TIM4_CH1, USART3_RTS |
| פין 71 | PD13 — GPIO PD13, TIM4_CH2 |
| פין 72 | PD14 — GPIO PD14, TIM4_CH3, UART8_CTS |
| פין 73 | PD15 — GPIO PD15, TIM4_CH4, UART8_RTS |
| פין 74 | VSS — Ground |
| פין 75 | VDD — Digital supply voltage |
| פין 76 | PE00 — GPIO PE0, TIM4_ETR, UART8_TX |
| פין 77 | PE01 — GPIO PE1, UART8_RX |
| פין 78 | PE07 — GPIO PE7, TIM1_ETR |
| פין 79 | PE08 — GPIO PE8, TIM1_CH1N |
| פין 80 | PE09 — GPIO PE9, TIM1_CH1 |
| פין 81 | VSS — Ground |
| פין 82 | VDD — Digital supply voltage |
| פין 83 | PE10 — GPIO PE10, TIM1_CH2N |
| פין 84 | PE11 — GPIO PE11, TIM1_CH2 |
| פין 85 | PE12 — GPIO PE12, TIM1_CH3N, SPI1_NSS |
| פין 86 | PE13 — GPIO PE13, TIM1_CH3, SPI1_SCK |
| פין 87 | PE14 — GPIO PE14, TIM1_CH4, SPI1_MISO |
| פין 88 | PE15 — GPIO PE15, TIM1_BKIN, SPI1_MOSI |
| פין 89 | PB10 — GPIO PB10 (alt) |
| פין 90 | PB11 — GPIO PB11 (alt) |
| פין 91 | VSS — Ground |
| פין 92 | VDD — Digital supply voltage |
| פין 93 | PC00 — GPIO PC0, ADC_IN10, TIM1_CH1 |
| פין 94 | PC01 — GPIO PC1, ADC_IN11, TIM1_CH2 |
| פין 95 | PC02 — GPIO PC2, ADC_IN12, SPI2_MISO |
| פין 96 | PC03 — GPIO PC3, ADC_IN13, SPI2_MOSI |
| פין 97 | VSSA — Analog ground |
| פין 98 | VREF+ — ADC reference voltage high |
| פין 99 | VDDA — Analog supply voltage |
| פין 100 | VREF- — ADC reference voltage low |
| פין 101 | PH00 — GPIO PH0, OSC_IN |
| פין 102 | PH01 — GPIO PH1, OSC_OUT |
| פין 103 | PH02 — GPIO PH2 |
| פין 104 | PA08 — GPIO PA8 (alt) |
| פין 105 | PA09 — GPIO PA9 (alt) |
| פין 106 | VSS — Ground |
| פין 107 | VDD — Digital supply voltage |
| פין 108 | PA10 — GPIO PA10 (alt) |
| פין 109 | PA11 — GPIO PA11 (alt) |
| פין 110 | PA12 — GPIO PA12 (alt) |
| פין 111 | PA13 — GPIO PA13 (alt) |
| פין 112 | PA14 — GPIO PA14 (alt) |
| פין 113 | PA15 — GPIO PA15 (alt) |
| פין 114 | PC04 — GPIO PC4, ADC_IN14 |
| פין 115 | PC05 — GPIO PC5, ADC_IN15 |
| פין 116 | PB00 — GPIO PB0 (alt) |
| פין 117 | PB01 — GPIO PB1 (alt) |
| פין 118 | PB02 — GPIO PB2 (alt) |
| פין 119 | VSS — Ground |
| פין 120 | VDD — Digital supply voltage |
| פין 121 | PB12 — GPIO PB12 (alt) |
| פין 122 | PB13 — GPIO PB13 (alt) |
| פין 123 | PB14 — GPIO PB14 (alt) |
| פין 124 | PB15 — GPIO PB15 (alt) |
| פין 125 | PC06 — GPIO PC6, TIM3_CH1 |
| פין 126 | PC07 — GPIO PC7, TIM3_CH2 |
| פין 127 | PC08 — GPIO PC8, TIM3_CH3, SDMMC1_D0 |
| פין 128 | PC09 — GPIO PC9, TIM3_CH4, SDMMC1_D1 |
| פין 129 | PA00 — GPIO PA0 (alt) |
| פין 130 | PA01 — GPIO PA1 (alt) |
| פין 131 | VSS — Ground |
| פין 132 | VDD — Digital supply voltage |
| פין 133 | PA02 — GPIO PA2 (alt) |
| פין 134 | PA03 — GPIO PA3 (alt) |
| פין 135 | PA04 — GPIO PA4 (alt) |
| פין 136 | PA05 — GPIO PA5 (alt) |
| פין 137 | PA06 — GPIO PA6 (alt) |
| פין 138 | PA07 — GPIO PA7 (alt) |
| פין 139 | PC10 — GPIO PC10, USART3_TX, I2S3_CK |
| פין 140 | PC11 — GPIO PC11, USART3_RX, I2S3_SD |
| פין 141 | PC12 — GPIO PC12, USART3_CK, I2S3_WS |
| פין 142 | PD00 — GPIO PD0 (alt) |
| פין 143 | PD01 — GPIO PD1 (alt) |
| פין 144 | VSS — Ground (bottom pad exposed thermal) |
יישומים טיפוסיים
STM32L471ZGT6 מתאים עבור 6 יישוםs: Industrial Sensor Hubs and IoT Gateways, Wearable Medical and Health Monitors, Smart Metering and Energy Monitoring, Low-Power Motor Control and Field-Oriented Control (FOC), Portable Consumer Devices and Battery IoT, Aerospace Telemetry and UAV Flight Controllers.
Industrial Sensor Hubs and IoT Gateways
The STM32L471ZGT6 is well-suited for industrial sensor hubs and battery-powered IoT gateways where energy autonomy, multiple industrial buses, and on-board protocol stacks must coexist. Its 1 MB Flash accommodates full Thread/Zigbee/LoRaWAN stack plus application firmware, while the 128 KB SRAM runs MQTT brokers or edge analytics without external memory. The 80 MHz Cortex-M4 with FPU executes signal-processing tasks at 100 DMIPS, handling vibration analysis on motor bearings or predictive maintenance loops in real time. Two CAN 2.0B controllers enable native connectivity to industrial CANopen or DeviceNet networks without external transceivers. According to ST datasheet, Stop2 mode at 1.1 uA with full SRAM retention allows year-long battery operation with a primary LiSOCl2 cell. Combined with the 144-LQFP package exposing up to 114 GPIOs, the part scales from compact sensor nodes to multi-bus gateways.
מומלץ
Wearable Medical and Health Monitors
For wearable medical monitors, the STM32L471ZGT6 offers a unique blend of DSP-grade Cortex-M4 compute with extreme energy efficiency. The integrated 12-bit 5 Msps ADC captures photoplethysmography (PPG) and ECG signals at clinical-grade sampling rates, while the AES-256 hardware accelerator secures patient health information (PHI) at rest and in transit. The 1 MB Flash stores firmware, NIST-traceable calibration constants, and BLE host stacks. Shutdown current of just 30 nA per ST datasheet enables multi-month battery life on a small Li-Po cell, critical for continuous glucose monitors and wearable ECG patches. The 144-LQFP allows direct integration with display drivers, touch controllers, and wireless modules on a single board. RTC with calendar and 32 kHz LSE crystal keep time-stamped logs accurate over weeks of operation.
מומלץ
Smart Metering and Energy Monitoring
The STM32L471ZGT6 is engineered for smart electricity, gas, and water metering applications where 10+ year battery life and regulatory metrology accuracy must coexist. Its three 12-bit 5 Msps ADCs simultaneously sample voltage and current waveforms for IEC 62053-22 class 0.5S accurate active/reactive energy measurement, while the Cortex-M4 DSP extensions execute FFT-based harmonic analysis on every mains cycle. Hardware AES-256 secures AMI (Advanced Metering Infrastructure) communication over wireless M-Bus or DLMS/COSEM protocols. Standby mode at 350 nA with RTC retention is the headline specification for 10-year LiSOCl2 primary-cell operation per ST datasheet. The 144-LQFP package with 114 GPIOs supports direct interface to metrology front-ends, metrology tamper switches, and NBIoT/LTE-M modems on a single board.
מומלץ
Low-Power Motor Control and Field-Oriented Control (FOC)
For battery-powered brushless DC (BLDC) and permanent-magnet synchronous motor (PMSM) drives, the STM32L471ZGT6 delivers Cortex-M4 + DSP compute for sensorless field-oriented control without a separate DSP chip. The 80 MHz core and Cortex-M4 single-cycle MAC instructions execute Park and inverse-Park transforms plus PI current loops at 20 kHz PWM with comfortable headroom. Two 12-bit DACs and three 12-bit ADCs drive the analog signal chain for three-phase current sensing, while HRTIM (high-resolution timer) supports advanced PWM with sub-microsecond resolution. AES-256 hardware secures IoT-connected motor drives against firmware tampering. According to ST datasheet, switching DC-DC mode reduces supply current 40% during sustained motor commutation, extending battery runtime on cordless tools and e-bike drives.
מומלץ
Portable Consumer Devices and Battery IoT
The STM32L471ZGT6 serves portable consumer electronics such as smart locks, GPS trackers, and wireless sensor peripherals where multi-day battery life and USB charging are first-class requirements. USB 2.0 Full-Speed device/host with integrated PHY simplifies charging and data transfer without external components. Stop2 mode at 1.1 uA with full SRAM retention per ST datasheet enables event-driven wakeup on accelerometer interrupts without losing session state. The 1 MB Flash accommodates rich Bluetooth Low Energy or proprietary 2.4 GHz protocol stacks plus secure bootloaders. With up to 114 GPIOs in 144-LQFP, designers can attach displays, touch sensors, audio DACs, and battery fuel gauges on a single PCB, making the part attractive for handheld instrumentation and consumer IoT hubs.
מומלץ
Aerospace Telemetry and UAV Flight Controllers
For UAV flight controllers and aerospace telemetry units, the STM32L471ZGT6 delivers aerospace-parity signal-processing compute with a hardened industrial temperature grade. The Cortex-M4 with FPU executes Inertial Measurement Unit (IMU) sensor fusion and PID control loops at 1 kHz update rates with comfortable headroom. Two CAN 2.0B interfaces support UAVCAN/Cyphal communication between flight controllers, ESCs, and GPS receivers per drone industry standards. Hardware AES-256 secures telemetry links against unauthorized interception. Stop2 mode at 1.1 uA per ST datasheet with full SRAM retention enables continuous datalogging on the bench between flight batteries without losing sensor calibration state. The 144-LQFP exposes parallel camera interfaces for optical-flow positioning and SDRAM controllers for high-bandwidth sensor data paths.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור STM32L471ZGT6 — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
השוואה עם חלופות
| פרמטר | מוצר זה | STM32L471RGT6 | STM32L471VGT6 | STM32L471QGI6 | STM32L452RET6P |
|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Package | LQFP-144 | LQFP-64 | LQFP-100 | UFBGA-132 | LQFP-64 |
| Core | Cortex-M4 + FPU | Cortex-M4 + FPU | Cortex-M4 + FPU | Cortex-M4 + FPU | Cortex-M4 + FPU |
| Flash | 1 MB | 1 MB | 1 MB | 1 MB | 256 KB |
| SRAM | 128 KB | 128 KB | 128 KB | 128 KB | 64 KB |
| Maximum Clock Frequency | 80 MHz | 80 MHz | 80 MHz | 80 MHz | 80 MHz |
| GPIO Count | 114 | 51 | 82 | 109 | 51 |
| Operating Voltage | 1.71 V to 3.6 V | 1.71 V to 3.6 V | 1.71 V to 3.6 V | 1.71 V to 3.6 V | 1.71 V to 3.6 V |
| CAN Controllers | 2 | 2 | 2 | 2 | 1 |
| AES-256 Hardware | Yes | Yes | Yes | Yes | Yes |
מבדילים עיקריים
- Highest pin count in STM32L471 family (לעומתSTM32L471RGT6)
- 1 MB Flash with FPU + DSP (לעומתSTM32L452RET6P)
- Full hardware AES-256 + 32 KB SRAM2a (לעומתSTM32L443RCT6)
הערות תכנון
The STM32L471ZGT6 ships with both LDO and integrated DC-DC buck converter (PWR_CR register PWR_LDO_SCALE bit). For battery applications demanding the lowest Stop2 current (1.1 uA per ST datasheet), select the LDO mode and disable the DC-DC converter. Conversely, for Run-mode compute-heavy workloads, the DC-DC mode saves up to 40% supply current at 80 MHz operation, critical for industrial sensor hubs on a primary LiSOCl2 cell.
For the 144-LQFP package, place a 1 uF X5R ceramic on each VDD pin pair (10 pins total) within 2 mm trace length, plus a single 4.7 uF bulk capacitor on the VDDA pin. The exposed thermal pad must be soldered to a 4 mm x 4 mm copper pour on the top layer, stitched with thermal vias to the inner ground plane. Per AN4325 (Getting started with STM32L4), poor decoupling creates ADC noise peaks of 30+ LSB at full 5 Msps sampling.
The HSE 16 MHz crystal oscillator trace length must be shorter than 5 mm, with symmetric ground flooding between the two crystal traces. Add a 5.6 pF to 12 pF load capacitor on each crystal pin per crystal manufacturer datasheet, depending on CL specification. For RTC accuracy, choose a 32.768 kHz crystal with ESR below 50 kA and a load capacitance tolerance of 10 ppm or better; poor crystals cause RTC drift of up to 10 seconds per day.
Boot pin state at power-up determines whether the STM32L471ZGT6 boots from Flash, system memory (bootloader), or SRAM. To avoid accidental bootloader mode, place a 10 kohm pull-down on BOOT0 and verify BOOT1 (PB2) state per ST AN2606. Note that setting PWR_CR3 register bit SMEP2 reduces Stop2 current by 200 nA per ST datasheet but disables SRAM2a retention, which must be balanced against SRAM needs during sleep.
מידע על תאימות
RoHS and REACH compliant per ST product page declaration. Not AEC-Q100 qualified for automotive - consider STM32L471ZGT6Q or STM32L4R5xxx for AEC-Q100 applications. Halogen-free per ST REACH presentation. Conflict minerals compliant per ST supplier policy.
