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Contents

README

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A3906SESTR-T

Allegro MicroSystems LLC · Stepper Motor Driver · QFN-20-EP(4x4)

A3906SESTR-T from Allegro MicroSystems LLC, in a QFN-20-EP(4x4). 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 CP2 passive Charge pump capacitor terminal 2; connect 0.1 μF ceramic capacitor between CP1 and CP2.
2 GND power_in Ground; low impedance connection to PCB ground plane.
3 SLEEP input Sleep logic input (active low); logic low disables output drivers and internal circuitry.
4 IN1 input Control input for bridge 1; accepts logic signals in range 0 to 5.5 V.
5 IN2 input Control input for bridge 1; accepts logic signals in range 0 to 5.5 V.
6 IN3 input Control input for bridge 2; accepts logic signals in range 0 to 5.5 V.
7 IN4 input Control input for bridge 2; accepts logic signals in range 0 to 5.5 V.
8 FL1 tri_state Current limit flag output for bridge 1; pulled low when peak current in motor winding reaches threshold determined by sense resistor.
9 FL2 tri_state Current limit flag output for bridge 2; pulled low when peak current in motor winding reaches threshold determined by sense resistor.
10 OUT2A output DMOS full-bridge 2 output A; source or sink output current up to 1 A continuous.
11 SENSE2 input Current sense input for bridge 2; analog voltage input maximum 0.5 V continuous or 1 V pulsed.
12 OUT2B output DMOS full-bridge 2 output B; source or sink output current up to 1 A continuous.
13 VBB power_in Supply voltage input; operating range 2.5 to 9 V for motor drive supply.
14 OUT1B output DMOS full-bridge 1 output B; source or sink output current up to 1 A continuous.
15 SENSE1 input Current sense input for bridge 1; analog voltage input maximum 0.5 V continuous or 1 V pulsed.
16 OUT1A output DMOS full-bridge 1 output A; source or sink output current up to 1 A continuous.
17 VCP passive Reservoir capacitor terminal; connect 0.1 μF ceramic capacitor between VCP and VBB for high-side gate drive supply.
18 CP3 passive Charge pump capacitor terminal 3; connect 0.1 μF ceramic capacitor between CP3 and CP4.
19 CP1 passive Charge pump capacitor terminal 1; connect 0.1 μF ceramic capacitor between CP1 and CP2.
20 CP4 passive Charge pump capacitor terminal 4; connect 0.1 μF ceramic capacitor between CP3 and CP4.
21 EP passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Allegro MicroSystems LLC
Package QFN-20-EP(4x4)
Category Motor Driver ICs
Pins 21

CAD (KiCad official)

  • Symbol: A3906SESTR-T
  • Footprint: Package_DFN_QFN:QFN-20-1EP_4x4mm_P0.5mm_EP2.5x2.5mm
  • 3D model: QFN-20-EP(4x4) (KiCad packages3D, STEP)
  • 3D model files: a3906sestr-t-etched.step / a3906sestr-t-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); a3906sestr-t.step / a3906sestr-t.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Allegro MicroSystems LLC datasheet (10 pp, sha256 7937a27a62d2477e, retrieved 2026-09-22, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.2, primary claude-haiku-4-5-20251001 (text), consensus claude-sonnet-4-6 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF