# LTE-SoundPayment ## Description Updated ERC-Cleaned Design Without Q2, C1, and C2 (ERC-verified removal of Q2 2N7002K, C1 10uF bulk, and C2 100nF decoupling; no changes to remaining power paths or circuitry) ## Project Details - **Owner:** circlebitlab - **Created:** 12/11/2025 - **Last Updated:** 12/12/2025 - **Visibility:** Public - **Power Requirements:** Battery, USB - **System Architecture:** ```mermaid flowchart TD subgraph System_Power_Architecture [System Power Architecture] J1["J1 Battery Connector"] --> BAT_RAIL[BAT rail] BAT_RAIL --> U4["U4 SLM6400 Charger"] BAT_RAIL --> U1["U1 A7670C-LASE LTE Module"] subgraph USB_C_Charge_Only [USB-C Charge-Only] J3["J3 USB-C Connector"] --> U4 end BAT_RAIL --> U6["U6 TPS62130 3V3 DC-DC"] U6 --> NET_3V3[3V3 rail] end ``` - **Connectivity:** Cellular, USB - **Project Description:** Battery-first power architecture for LTE-SoundPayment with USB-C charging (charge-only) and TPS62130-based 3.3 V regulation supplying an A7670C-LASE LTE module and associated circuitry. - **BAT Net Connections:** Q1:D, U1:VBAT, U6:AVIN, L1:P1, L1:P2, C3:P1, U4:BAT - **Domain:** Telecommunications ## Key Components ### — [Texas Instruments 2.4 GHz Inverted F Antenna Copper Only c5dc](https://www.flux.ai/ryanf/texas-instruments-2p4-ghz-inverted-f-antenna-copper-only-c5dc~hgq.md) - Design Company: Texas Instruments - Antenna: Inverted F Antenna - Antenna Frequency: 2.4GHz - Application Note: https://www.ti.com/lit/an/swru120d/swru120d.pdf?ts=1721933214057&ref_url=https%253A%252F%252Fwww.google.com%252F **Pins:** - Antenna_Left - Antenna_Right - GND - GND - IN ### AN1 — Custom PCB Antenna - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Antenna **Pins:** - 1 [pin 1] - 2 [pin 2] ### ANT1 — [PCB Antenna](https://www.flux.ai/collinsemasi/pcb-antenna~k5.md) - Part Type: Antenna - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - 1 [pin 1] - 2 [pin 2] ### D1 — [ESD321DPYR](https://www.flux.ai/corvus96/esd321dpyr~2s.md) - Manufacturer Part Number: ESD321DPYR - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd321.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1690491326127&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Fesd321 - Manufacturer Name: Texas Instruments - Package: SMD_0402_1005Metric - Role Details: ESD protection for J3 CC1 - Role: Protection **Pins:** - GND [pin 2] - IO [pin 1] ### D2 — [ESD321DPYR](https://www.flux.ai/corvus96/esd321dpyr~2s.md) - Manufacturer Part Number: ESD321DPYR - Manufacturer Name: Texas Instruments - Datasheet URL: https://www.ti.com/lit/ds/symlink/esd321.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1690491326127&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Fesd321 - Package: SMD_0402_1005Metric - Role: Protection - Role Details: ESD protection for J3 CC2 **Pins:** - GND [pin 2] - IO [pin 1] ### D3 — [USBLC6-2SC6Y](https://www.flux.ai/adrian95/usblc6-2sc6y~2s7.md) - Role: Protection - Datasheet URL: https://www.st.com/content/ccc/resource/technical/document/datasheet/group0/94/15/6c/58/ba/91/46/42/DM00055262/files/DM00055262.pdf/jcr:content/translations/en.DM00055262.pdf - Role Details: TVS diode for USB VBUS transient suppression - Manufacturer Part Number: USBLC6-2SC6Y - Manufacturer Name: STMicroelectronics - Part Type: Protection - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - GND [pin 2] - I/O1 [pin 6] - I/O1 [pin 1] - I/O2 [pin 3] - I/O2 [pin 4] - VBUS [pin 5] ### J2 — [S2B-PH-K-S(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-k-slfsn~brb.md) - Manufacturer Name: JST Sales America Inc. - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: S2B-PH-K-S(LF)(SN) **Pins:** - P1 [pin 1] - P2 [pin 2] ### J3 — [Type-C-2.0-6Pin](https://www.flux.ai/jharwinbarrozo/type-c-2p0-6pin~wh.md) - Datasheet URL: https://datasheet.lcsc.com/lcsc/2204071830_CIKI-Type-C-2-0-6Pin_C2987385.pdf - Manufacturer Part Number: Type-C-2.0-6Pin - Part Type: Connector - Manufacturer Name: CIKI **Pins:** - CC1 - CC2 - GND - GND__1 - SHIELD - SHIELD__1 - SHIELD__2 - SHIELD__3 - V-BUS - V-BUS__1 ### LED1 — [LED-0805-Template](https://www.flux.ai/vasy_skral/led-0805-template~dfa.md) - Part Type: LED - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - A [pin 2] - K [pin 1] ### LED2 — [LED-0805-Template](https://www.flux.ai/vasy_skral/led-0805-template~dfa.md) - Part Type: LED - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - A [pin 2] - K [pin 1] ### Q1 — [AO4407A-VB](https://www.flux.ai/lcsc/ao4407a-vb~lyfu.md) - Package or Case Code: SOP-8_L4.9-W3.9-P1.27-LS6.0-BL - LCSC Part Number: C557949 - Part Type: MOSFETs - JLCPCB Part Class: Extended Part - Manufacturer Name: VBsemi(微碧半导体) - Manufacturer Part Number: AO4407A-VB **Pins:** - D [pin 6] - D [pin 7] - D [pin 8] - D [pin 5] - G [pin 4] - S [pin 2] - S [pin 3] - S [pin 1] ### Q2 — [2N7002K](https://www.flux.ai/jecstronic/2n7002k~8y.md) - Manufacturer Part Number: 2N7002K - Part Type: Transistor - Datasheet URL: https://www.infineon.com/dgdl/Infineon-2N7002-DS-v02_04-en.pdf - Manufacturer Name: MDD - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Q3 — [S2B-PH-K-S(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-k-slfsn~brb.md) - Part Type: Connector - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - Manufacturer Name: JST Sales America Inc. - Manufacturer Part Number: S2B-PH-K-S(LF)(SN) - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - P1 [pin 1] - P2 [pin 2] ### SW1 — [B3U-3000P](https://www.flux.ai/adrian95/b3u-3000p~l3s.md) - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3u.pdf - Manufacturer Name: Omron Electronics Inc-EMC Div - Part Type: Switch - Manufacturer Part Number: B3U-3000P **Pins:** - 1 [pin 1] - 2 [pin 2] ### SW2 — [B3U-3000P](https://www.flux.ai/adrian95/b3u-3000p~l3s.md) - Manufacturer Name: Omron Electronics Inc-EMC Div - Datasheet URL: https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3u.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Switch - Manufacturer Part Number: B3U-3000P **Pins:** - 1 [pin 1] - 2 [pin 2] ### SW3 — [B3U-3000P](https://www.flux.ai/adrian95/b3u-3000p~l3s.md) - Datasheet URL: https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3u.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Omron Electronics Inc-EMC Div - Part Type: Switch - Manufacturer Part Number: B3U-3000P **Pins:** - 1 [pin 1] - 2 [pin 2] ### U1 — [A7670C-LASE](https://www.flux.ai/lcsc/a7670c-lase~cbwy.md) - Manufacturer Name: SIMCOM(芯讯通无线科技) - Package or Case Code: LGA-124_L24.0-W24.0-P1.0-A7670C-LASS - LCSC Part Number: C2888406 - Manufacturer Part Number: A7670C-LASE - JLCPCB Part Class: Extended Part **Pins:** - 1PPS [pin 100] - 1V8_GNSS [pin 97] - ADC [pin 25] - AP_WAKEUP [pin 3] - BT_ANT [pin 93] - EAR_N [pin 41] - EAR_P [pin 40] - GND [pin 76] - GND [pin 18] - GND [pin 77] - GND [pin 84] - GND [pin 75] - GND [pin 81] - GND [pin 85] - GND [pin 88] - GND [pin 39] - GND [pin 87] - GND [pin 58] - GND [pin 79] - GND [pin 71] - GND [pin 91] - GND [pin 80] - GND [pin 82] - GND [pin 94] - GND [pin 2] - GND [pin 89] - GND [pin 83] - GND [pin 92] - GND [pin 61] - GND [pin 59] - GND [pin 64] - GND [pin 46] - GND [pin 70] - GND [pin 62] - GND [pin 65] - GND [pin 73] - GND [pin 54] - GND [pin 74] - GND [pin 72] - GND [pin 69] - GND [pin 17] - GND [pin 86] - GND [pin 45] - GND [pin 63] - GND [pin 78] - GND [pin 29] - GNSS_ANT [pin 90] - GNSS_PWR_EN/MK_IN_3 [pin 20] - GNSS_PWRCTL [pin 98] - GNSS_RXD [pin 96] - GNSS_TXD [pin 95] - GNSS_VBKP [pin 116] - GPIO_00 [pin 4] - GPIO_01 [pin 5] - GPIO_02 [pin 6] - GPIO_03 [pin 7] - GPIO_04 [pin 8] - GPIO_05 [pin 19] - GPIO_07/MK_OUT_3 [pin 21] - GPIO_08 [pin 48] - GPIO_09 [pin 52] - GPIO_10 [pin 66] - GPIO_11/MK_OUT_5 [pin 67] - GPIO_12/MK_IN_5 [pin 68] - GPIO_13/MK_OUT_6 [pin 35] - GPIO_14/MK_IN_6 [pin 36] - GPIO_15/MK_OUT_2 [pin 44] - GPIO_16/MK_IN_2 [pin 47] - GPIO_17 [pin 26] - GPIO_18 [pin 53] - GPIO_19/LCD_BL_PWM [pin 101] - GPIO_20/LCD_SPI_CLK [pin 102] - GPIO_21/LCD_SPI_TXD [pin 103] - GPIO_22/LCD_SPI_RXD [pin 104] - GPIO_23/LCD_SPI_CS [pin 105] - GPIO_24/LCD_RST [pin 106] - GPIO_25/LCD_DCX [pin 107] - GPIO_26 [pin 117] - GPIO_27 [pin 118] - GPIO_28 [pin 119] - GPIO_29 [pin 120] - GPIO_30 [pin 121] - GPIO_31 [pin 122] - GPIO_32 [pin 123] - GPIO_33 [pin 124] - I2C_SCL [pin 38] - I2C_SDA [pin 37] - MIC_N [pin 43] - MIC_P [pin 42] - NC [pin 114] - NC [pin 113] - NC [pin 115] - PWRKEY [pin 1] - RESET [pin 16] - RF_ANT [pin 60] - RXD [pin 10] - SPI_CLK [pin 11] - SPI_CS [pin 12] - SPI_MISO [pin 14] - SPI_MOSI [pin 13] - TXD [pin 9] - UART_LOG_RX [pin 22] - UART_LOG_TX [pin 23] - UART3_RXD [pin 49] - UART3_TXD [pin 50] - USB_DM [pin 28] - USB_DP [pin 27] - USIM1_CLK [pin 32] - USIM1_DATA [pin 31] - USIM1_DET [pin 34] - USIM1_RST [pin 33] - USIM1_VDD [pin 30] - USIM2_CLK [pin 109] - USIM2_DATA [pin 108] - USIM2_DET [pin 112] - USIM2_RST [pin 111] - USIM2_VDD [pin 110] - VBAT [pin 56] - VBAT [pin 57] - VBAT [pin 55] - VBAT_ADC [pin 51] - VBUS [pin 24] - VDD_1V8 [pin 15] - VDD_2V8 [pin 99] ### U2_CHG — [W25Q64JVSSIQ](https://www.flux.ai/lcsc/w25q64jvssiq~ias3.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1912211532_Winbond-Elec-W25Q64JVSSIQ_C179171.pdf - Package or Case Code: SOIC-8_L5.3-W5.3-P1.27-LS8.0-BL - Manufacturer Part Number: W25Q64JVSSIQ - Voltage Supply: 2.7 ~ 3.6V - Manufacturer Name: WINBOND(华邦) - Operating Temperature: -40°C ~ 85°C (TA) - Part Type: NOR FLASH - LCSC Part Number: C179171 - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/New-Arrivals_Winbond-Elec-W25Q64JVSSIQ_C179171.html - Frequency: 133MHz **Pins:** - ~{CS} [pin 1] - CLK [pin 6] - DI(IO0) [pin 5] - DO(IO1) [pin 2] - GND [pin 4] - HOLD#orRESET#(IO3) [pin 7] - VCC [pin 8] - WP#(IO2) [pin 3] ### U3 — [FM8002E](https://www.flux.ai/lcsc/fm8002e~6ft0.md) - Part Type: Audio Power OpAmps - Manufacturer Part Number: FM8002E - Package or Case Code: SOP-8_L4.9-W3.9-P1.27-LS6.0-BL - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/Others_Shenzhen-Fuman-Elec-FM8002E_C340921.html - Manufacturer Name: FM(富满) - LCSC Part Number: C340921 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2202251530_Shenzhen-Fuman-Elec-FM8002E_C340921.pdf **Pins:** - -IN [pin 4] - +IN [pin 3] - BYPASS [pin 2] - GND [pin 7] - SHUTDOWN [pin 1] - VDD [pin 6] - VO1 [pin 5] - VO2 [pin 8] ### U4 — [SLM6400](https://www.flux.ai/lcsc/slm6400~bgrf.md) - Product Info Url: https://lcsc.com/product-detail/Others_SOLA-IC-SLM6400_C338664.html - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2007231614_SOLA-IC-SLM6400_C338664.pdf - Manufacturer Part Number: SLM6400 - Part Type: Battery Management ICs - Manufacturer Name: 无锡松朗微 - JLCPCB Part Class: Extended Part - Package or Case Code: DFN-8_L3.0-W3.0-P0.65-BL-EP - LCSC Part Number: C338664 **Pins:** - BAT [pin 5] - EP [pin 9] - GND [pin 3] - NCE [pin 8] - NCH [pin 7] - NPG [pin 6] - NTC [pin 1] - PROG [pin 2] - VCC [pin 4] ### U6 — [TPS62130ARGTR](https://www.flux.ai/ryanf/tps62130argtr~8k9.md) - Manufacturer Part Number: TPS62130ARGTR - Part Type: Switching Regulator - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps62130a.pdf?ts=1716649051225&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS62130A - License: https://creativecommons.org/licenses/by/4.0/ - Package or Case Code: QFN50P300X300X50-17N - Manufacturer Name: Texas Instruments **Pins:** - AGND [pin 6] - AGND [pin 17] - AVIN [pin 10] - DEF [pin 8] - EN [pin 13] - FB [pin 5] - FSW [pin 7] - PG [pin 4] - PGND [pin 16] - PGND [pin 15] - PVIN [pin 12] - PVIN [pin 11] - SS/TR [pin 9] - SW [pin 2] - SW [pin 3] - SW [pin 1] - VOS [pin 14] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/circlebitlab/lte-soundpayment~yt](https://www.flux.ai/circlebitlab/lte-soundpayment~yt).* --- *Generated from [https://www.flux.ai/circlebitlab/lte-soundpayment~yt](https://www.flux.ai/circlebitlab/lte-soundpayment~yt)*