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A3944KLPTR-T

Allegro MicroSystems, LLC · Motor Driver ICs · TSSOP-28-EP

A3944KLPTR-T from Allegro MicroSystems, LLC, in a TSSOP-28-EP. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 VDR power_in Positive gate drive supply for the GATx outputs, with an absolute maximum rating of -0.3 to 6.5 V.
2 GAT0 output Gate drive 0 output, driven between GND and VDR and connected directly or through a resistor to the external MOSFET gate.
3 DRN0 input Gate drive 0 drain sense analog high-voltage input, rated to 50 V, used to monitor the FET drain for short-to-battery, short-to-ground and open-load faults.
4 GAT1 output Gate drive 1 output, driven between GND and VDR and connected directly or through a resistor to the external MOSFET gate.
5 DRN1 input Gate drive 1 drain sense analog high-voltage input, rated to 50 V, used to monitor the FET drain for short-to-battery, short-to-ground and open-load faults.
6 GAT2 output Gate drive 2 output, driven between GND and VDR and connected directly or through a resistor to the external MOSFET gate.
7 DRN2 input Gate drive 2 drain sense analog high-voltage input, rated to 50 V, used to monitor the FET drain for short-to-battery, short-to-ground and open-load faults.
8 GAT3 output Gate drive 3 output, driven between GND and VDR and connected directly or through a resistor to the external MOSFET gate.
9 DRN3 input Gate drive 3 drain sense analog high-voltage input, rated to 50 V, used to monitor the FET drain for short-to-battery, short-to-ground and open-load faults.
10 GAT4 output Gate drive 4 output, driven between GND and VDR and connected directly or through a resistor to the external MOSFET gate.
11 DRN4 input Gate drive 4 drain sense analog high-voltage input, rated to 50 V, used to monitor the FET drain for short-to-battery, short-to-ground and open-load faults.
12 GAT5 output Gate drive 5 output, driven between GND and VDR and connected directly or through a resistor to the external MOSFET gate.
13 DRN5 input Gate drive 5 drain sense analog high-voltage input, rated to 50 V, used to monitor the FET drain for short-to-battery, short-to-ground and open-load faults.
14 VREG power_out Regulated voltage output for analog and reference functions, with an absolute maximum rating of -0.3 to 20 V.
15 VBB power_in Analog battery supply for the voltage regulator, which can connect to battery through reverse polarity protection, with an absolute maximum rating of -0.3 to 40 V.
16 GND power_in Power ground return that connects to the common return point for all external MOSFET source connections.
17 IN5 input Gate drive 5 active-high control input with internal pull-down to GND, rated -0.3 to 6.5 V.
18 IN4 input Gate drive 4 active-high control input with internal pull-down to GND, rated -0.3 to 6.5 V.
19 IN3 input Gate drive 3 active-high control input with internal pull-down to GND, rated -0.3 to 6.5 V.
20 IN2 input Gate drive 2 active-high control input with internal pull-down to GND, rated -0.3 to 6.5 V.
21 IN1 input Gate drive 1 active-high control input with internal pull-down to GND, rated -0.3 to 6.5 V.
22 IN0 input Gate drive 0 active-high control input with internal pull-down to GND, rated -0.3 to 6.5 V.
23 CSN input Active-low serial interface chip select with pull-up resistor; data is latched into the serial register when CSN goes high, rated -0.3 to 6.5 V.
24 SI input Active-high serial data input with pull-down resistor, clocked into the serial register on the rising edge of SCK, rated -0.3 to 6.5 V.
25 SCK input Serial interface clock input with pull-down resistor, rated -0.3 to 6.5 V.
26 SO output Push-pull serial data output that carries fault register data on the falling edge of SCK and goes high impedance when CSN is high, rated -0.3 to 6.5 V.
27 RESETN input Active-low chip reset input that forces outputs low, resets the configuration and clears channel faults when held low longer than the minimum reset pulse width, rated -0.3 to 6.5 V.
28 VDD power_in Positive logic supply for digital inputs, outputs and logic, with an absolute maximum rating of -0.3 to 6.5 V.
29 PAD passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Allegro MicroSystems, LLC
Package TSSOP-28-EP
Category Power Management ICs
Pins 29

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
Analog Supply Voltage VBB -0.3 40 V with respect to ground at TA = 25°C 2
Logic Supply Voltage VDD -0.3 6.5 V with respect to ground at TA = 25°C 2
Gate Drive Supply Voltage VDR -0.3 6.5 V with respect to ground at TA = 25°C 2
Terminal VREG VREG -0.3 20 V with respect to ground at TA = 25°C 2
Terminals GATx GATx -0.3 6.5 V with respect to ground at TA = 25°C 2
Terminals DRNx DRNx -0.3 50 V with respect to ground at TA = 25°C 2
Terminals INx INx -0.3 6.5 V with respect to ground at TA = 25°C 2
Terminals SI, SCK, CSN -0.3 6.5 V with respect to ground at TA = 25°C 2
Terminal SO SO -0.3 6.5 V with respect to ground at TA = 25°C 2
Terminal RESETN RESETN -0.3 6.5 V with respect to ground at TA = 25°C 2
Drain Feedback Clamp Energy EDRNC 10 µJ Single pulse less than 2 ms 2
Drain Feedback Clamp Current IDRNC 100 mA Single pulse not exceeding EDRN or PDRN 2
Drain Feedback Clamp Power PDRNC 100 mW Average power over any 2 ms period 2
Junction Temperature TJ(max) 150 °C 2
Transient Junction Temperature TtJ 175 °C Overtemperature event not exceeding 10 s, lifetime duration not exceeding 10 hours 2
Storage Temperature Range Tstg -55 150 °C 2
Operating Temperature Range, Range K TA -40 150 °C Range K 2
Logic Supply Voltage VDD 3 5.5 V Valid at TJ = -40°C to 150°C 6
Analog Supply Voltage VBB 6 40 V Valid at TJ = -40°C to 150°C 6
Gate Drive Supply Voltage VDR 3 6 V Valid at TJ = -40°C to 150°C 6
VDD Quiescent Current IDDQ 3 mA 6
VBB Quiescent Current IBBQ 4 mA 6
VBB Quiescent Current IBBQ 10 µA VDD = 0, VBB ≤ 30 V 6
VDR Quiescent Current IDRQ 4 mA 6
Regulator Voltage VREG 17.5 18.5 V VBB > 19.5 V 6
Regulator Dropout VDO 0 0.6 V 6
RESETN Pulse Width tRST 1 µs 6
RESETN Glitch Filter tRGF 200 ns 6
Oscillator Frequency fOSC 1.4 2 2.6 MHz 6
Input High Voltage VIH 70 %VDD 6
Input Low Voltage VIL 30 %VDD 6
Input Hysteresis VIhys 300 500 mV 6
SO Output Low Voltage VOL 0.2 0.4 V SO, IOL = 2 mA 6
SO Output Leakage IL -1 1 µA CSN = VDD 6
Pull-Up On-Resistance RDS(on)UP 50 70 Ω TJ = 25°C, IGHx = -20 mA 6
Pull-Up On-Resistance RDS(on)UP 75 125 Ω TJ = 150°C, IGHx = -20 mA 6
Pull-Down On-Resistance RDS(on)DN 50 95 Ω TJ = 25°C, IGLx = 20 mA 6
Pull-Down On-Resistance RDS(on)DN 75 145 Ω TJ = 150°C, IGLx = 20 mA 6
Output Sink Current IGL 20 mA GATx off, VGATx = VDR 6
Output Source Current IGH -40 mA GATx on, VGATx = 0 V 6
Minimum On-Time ton 1 µs At INx input 6
Minimum Off-Time toff 1 µs At INx input 6
RESETN to GATx 0.5 1 µs 6
Drain Clamp Voltage VDCL 45 V IDRNx = 10 µA 7
Drain Clamp Leakage IDC 1 µA VDRNx < 32 V 7
VDD Undervoltage Lockout VDDUV 2.6 2.75 2.9 V Decreasing VDD 8
VREG Undervoltage Lockout VREGUV 4.5 4.8 5.1 V Decreasing VREG 8
Overtemperature Warning Threshold TJW 145 160 175 ºC Temperature increasing 8
Short-to-Battery Threshold VSTB 30 31 32 %VREG GATx driven high, SB[2:0] = 111 7
Pull-Up Diagnostic Current IDPU -80 -65 -50 µA GATx low, VDRNx < (VOCL, 200 mV) 7
Pull-Down Diagnostic Current IDPD 50 65 80 µA GATx low, NPD = 0, VDRNx >(VOCL + 200 mV) 7
Short-to-Ground Threshold VSTG 65 66 67 %VREG GATx driven low, SG = 1 7
Short-to-Ground Threshold VSTG 44 45 46 %VREG GATx driven low, SG = 0 7
Open-Load Threshold VOL 75 76 77 %VREG GATx driven low 7
Open-Load Clamp Voltage VOCL 70 71 72 %VREG 7
Package Thermal Resistance, Junction to Ambient RθJA 28 ºC/W 4-layer PCB based on JEDEC standard 2
Package Thermal Resistance, Junction to Ambient RθJA 32 ºC/W 2-layer PCB with 3.8 in.2 of copper area each side 2
Package Thermal Resistance, Junction to Pad RθJP 2 ºC/W 2
Drain Clamp Voltage VDCL 54 V IDRNx = 10 mA 7

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part Material Colour / plating Datasheet says Page
contacts tin LP) with an exposed thermal pad. The package is lead (Pb) free with 100% matte-tin leadframe plating. 1

CAD (KiCad official)

  • Symbol: A3944KLPTR-T
  • Footprint: Package_SO:TSSOP-28-1EP_4.4x9.7mm_P0.65mm_EP2.85x6.7mm
  • 3D model: TSSOP-28-EP (KiCad packages3D, STEP)
  • 3D model files: a3944klptr-t-etched.step / a3944klptr-t-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); a3944klptr-t.step / a3944klptr-t.glb are the bare package body.

Provenance

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

  • Datasheet: Allegro MicroSystems, LLC datasheet (31 pp, sha256 01679bb65c0b7218, retrieved 2026-10-28, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-sonnet-5-5 (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