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Ryan Malloy e3642cbc4e Initial commit: Heltec Wireless Tracker documentation site 
Astro/Starlight documentation covering hardware specs, pinout,
schematics, GNSS protocol, LoRa frequencies, and getting started
guides. Includes extracted datasheet images and Docker deployment.
2026-02-21 18:39:46 -07:00

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HTIT-Tracker V0.5 Schematic

Document Metadata

  • Format: PDF 1.4
  • Title: New Output
  • Keywords: Altium
  • Creator: Altium Designer
  • Producer: llPDFLib 3.x
  • Creation Date: 2023-07-31

Schematic Components

This is the full schematic for the Heltec Wireless Tracker V0.5, designed in Altium Designer.

Power Management

Component Value/Part Function
F1 6V 500mA Fuse
D1 RSB6.8S TVS Diode
D2 1N5819 Schottky Diode
Q1 AO3401 P-channel MOSFET
U2 TP4054 LiPo Charger IC
U4 CE6260B33M 3.3V LDO
U6 CE6260B33M 3.3V LDO (Vext)
R16 2K/5% Charge current set

ESP32-S3FN8 Main MCU (U7)

Crystal:

Component Value
U5 40MHz Crystal
C19, C20 22pF/10V
X1 32.768KHz (RTC)
C8, C22 4.7pF/10V

Key GPIO Connections:

  • GPIO0: USER_Key
  • GPIO1: Vbat_Read (via ADC)
  • GPIO2: ADC_Ctrl
  • GPIO3: Vext_Ctrl
  • GPIO8: LoRa_NSS
  • GPIO9: LoRa_SCK
  • GPIO10: LoRa_MOSI
  • GPIO11: LoRa_MISO
  • GPIO12: LoRa_RST
  • GPIO13: LoRa_BUSY
  • GPIO14: DIO1
  • GPIO18: LED Write Ctrl
  • GPIO19/20: USB_D-/USB_D+
  • GPIO21: LED_K (TFT backlight)
  • GPIO33: GNSS_TX
  • GPIO34: GNSS_RX
  • GPIO35: GNSS_RST
  • GPIO36: GNSS_PPS
  • GPIO38-42: TFT Display (CS, RES, RS, SCLK, SDIN)
  • GPIO47: BOOT_MODE
  • GPIO48: D_SEL

SX1262 LoRa Module (U12)

Component Value Function
L1 2.7nH RF matching
L2 24nH RF filter
L3 2.0nH RF matching
C12, C15, C18, C25 0.1uF Decoupling
C13, C14 1.8pF RF matching
U11 UPG2179 RF Switch
X4 32MHz TCXO
E4 IPEX LoRa Antenna

UC6580 GNSS Module (U9)

Component Value Function
X2 26MHz TCXO
X3 32.768KHz RTC Crystal
C34, C41 4.7pF Crystal load
R27 10K/5% Reset pullup
U8 HDDL1L5RSS-B8 L1/L5 LNA
U10 SW7125DE RF Amplifier
E3 IPEX GNSS Antenna

RF Frontend:

Component Value
L4 68nH
L5 1nH
L6 2.2nH
L7 18nH
L8 0R/5%
L9 6.8nH
L10 7nH
L11 4.5nH
EL2 1uH (inductor)

TFT Display (U1 - 0.96" OLED)

Pin Signal
SDIN GPIO42
SCLK GPIO41
RS GPIO40
RES GPIO39
CS GPIO38
LED_K GPIO21 (via Q4)

USB Type-C (U3)

Pin Signal
VBUS VDD_5V
DN1/DN2 USB_N
DP1/DP2 USB_P
CC1 R3 (5.1K to GND)
CC2 R6 (5.1K to GND)

Battery Management

Component Value Function
JP3 1.25X2P-LiPo Battery connector
C1 10uF/10V Input cap
C2 220nF/10V Charge cap
R13 390K/1% Voltage divider
R14 100K/1% Voltage divider
Q2 AO3401 Power switch
Q3 S9013 ADC control

LEDs

LED Color Resistor Function
LED1 Orange R7 (330R) Charging indicator
LED2 White R10 (330R) User LED

Buttons

Button Function
S1 RESET_SW
S2 USER_SW (GPIO0)

Pin Headers

Header P2 (8-pin)

Power and ground pins

Header P3 (8-pin)

Additional GPIO

Header P4 (16-pin)

Main GPIO header J2

Header P5 (16-pin)

Main GPIO header J3

Schematic Detail