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hd688adr
Public Unreviewedby Ray
Broadic RS-485/RS-422 ICs, SOP-16. Datasheet-verified pinout, KiCad symbol/footprint/3D.
3D Model
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markdownHD688ADR
Broadic · RS-485/RS-422 ICs · SOP-16
HD688ADR from Broadic, in a SOP-16. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | BUSL2 | passive | Meter-bus line 2 connection. One of the two polarity-insensitive M-Bus terminals; typically connected to the bus through a series protection resistor (RL2 ≈ 220 Ω). |
| 2 | VB | passive | Rectified bus voltage output. Provides the rectified M-Bus signal after the internal bridge (BR); reference for VSTC and the PF undervoltage detector. |
| 3 | STC | passive | External power-hold capacitor pin (CSTC). Stores energy from the bus to keep VDD alive during transmit modulation; recommended CSTC ≥ 50 µF (≤220 µF at RRIDD=13 kΩ, ≤470 µF at RRIDD=30 kΩ). |
| 4 | RIDD | passive | External resistor pin to set CS1 quiescent bus current. RRIDD = 13-80 kΩ (13 kΩ → IBUS ≈ 3 mA, 30 kΩ → IBUS ≈ 1.5 mA); VRIDD ≈ 1.23-1.33 V at 30 kΩ. |
| 5 | PF | output | Power-fail / undervoltage indication output. Signals bus undervoltage: high (≈VBAT − 0.6 V) when VVB ≥ VSTC + 0.8 V, low (≤0.9 V) when VVB ≤ VSTC + 0.3 V. |
| 6 | SC | passive | External sample/hold capacitor pin (CSC) for the receiver's dynamic threshold circuit. Charging current typ. −15 to −40 µA at VSC = 24 V; VSC tracks VVB. |
| 7 | TXI | output | Inverted transmit data output. Complementary to TX; VOH ≈ VBAT − 0.6 V at IOH = −100 µA, VOL ≤ 0.5 V at IOL = 100 µA. Used together with TX to drive the bus modulator (optionally via an optocoupler). |
| 8 | TX | output | Transmit data output (non-inverted). Drives the bus current-modulator; VOH ≈ VBAT − 0.6 V, VOL ≤ 1.5 V at 1.1 mA sink. Modulation current IMC ≈ 11.5-19.5 mA with RRIS = 100 Ω. |
| 9 | BAT | power_in | Logic-level reference / battery input. Sets the TX/TXI output high level and RX/RXI input high threshold; VBAT range 2.5-3.8 V (abs max 5.5 V), and must satisfy VBAT(max) ≤ VSTC − 1 V. |
| 10 | VS | output | Bus/battery supply-mode switch output. Drives an external P-MOSFET (e.g. BSS84) to gate battery supply: pulled to ≈VSTC when VDD is on (bus supply available), high-impedance (≈0.3-1 MΩ) when VDD is off so the battery can take over. |
| 11 | VDD | power_out | Regulated 3.3 V supply output for the slave/sensor system. VVDD = 3.1-3.4 V at IVDD = 1 mA (VSTC = 6.5 V); output resistance ≈5 Ω at 2-8 mA. |
| 12 | RX | input | Received data input from the host UART (non-inverted). VIH ≥ VBAT − 0.8 V (up to 5.5 V when VSTC ≥ 6.5 V), VIL ≤ 0.8 V; IRX ≈ −10 to −40 µA at VRX = 0 V. |
| 13 | RXI | input | Inverted received data input, complementary to RX. Same VIH/VIL thresholds as RX; IRXI ≈ 10-40 µA. Together RX/RXI form the differential control for the transmit modulator. |
| 14 | RIS | passive | External resistor pin (RRIS) that sets the bus modulation (send) current. RRIS ≥ 100 Ω → IMC ≈ 11.5-19.5 mA; VRIS ≈ 1.4-1.7 V at 100 Ω. |
| 15 | GND | power_in | Ground reference. All device voltages are referenced to this pin. |
| 16 | BUSL1 | passive | Meter-bus line 1 connection. The other polarity-insensitive M-Bus terminal; typically connected to the bus through a series protection resistor (RL1 ≈ 220 Ω). Absolute-max differential VMB(BUSL2-BUSL1) = ±50 V. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Broadic |
| Package | SOP-16 |
| Category | Comm/UART |
| Pins | 16 |
Ordering variants
HD688ADR
CAD (KiCad official)
- Symbol:
HD688ADR - Footprint:
Package_SO:SOIC-16_3.9x9.9mm_P1.27mm - 3D model: SOP-16 (KiCad packages3D, STEP)
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Broadic datasheet (None pp, sha256
45fd2a29fcb48791, retrieved 2026-08-17, tier: lcsc) - Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- Extractor:
ds2sf(Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate. - CAD: KiCad official libraries (CC-BY-SA 4.0).