ACS709LLFTR-35BB-T from Allegro MicroSystems, LLC, in a QSOP-24. 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	IP+	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP- pins, with unidirectional or bidirectional current flow.
2	IP+	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP- pins, with unidirectional or bidirectional current flow.
3	IP+	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP- pins, with unidirectional or bidirectional current flow.
4	IP+	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP- pins, with unidirectional or bidirectional current flow.
5	IP+	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP- pins, with unidirectional or bidirectional current flow.
6	IP+	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP- pins, with unidirectional or bidirectional current flow.
7	IP-	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP+ pins, with unidirectional or bidirectional current flow.
8	IP-	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP+ pins, with unidirectional or bidirectional current flow.
9	IP-	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP+ pins, with unidirectional or bidirectional current flow.
10	IP-	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP+ pins, with unidirectional or bidirectional current flow.
11	IP-	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP+ pins, with unidirectional or bidirectional current flow.
12	IP-	passive	Sensed current copper conduction path pin; terminal for the current being sensed, fused internally and looped to the IP+ pins, with unidirectional or bidirectional current flow.
13	NC	unconnected	No connection.
14	NC	unconnected	No connection.
15	GND	power_in	Device ground connection.
16	VZCR	output	Voltage reference output pin giving a zero-current (0 A) reference whose output voltage scales with VCC.
17	FILTER	passive	Filter pin; connect an external capacitor from this pin to GND to set the device bandwidth.
18	VIOUT	output	Analog output pin whose output voltage is proportional to the current flowing through the loop between the IP+ and IP- pins.
19	FAULT	output	Overcurrent Fault pin that transitions to a logic low state when the current between the IP+ and IP- pins exceeds the overcurrent fault threshold.
20	VCC	power_in	Supply voltage pin.
21	VOC	input	Overcurrent Input pin; the analog input voltage on this pin sets the overcurrent fault threshold.
22	FAULT_EN	input	Fault enable pin that enables overcurrent faulting when high and resets the FAULT output when low.
23	NC	unconnected	No connection.
24	NC	unconnected	No connection.

Key specifications

Parameter	Value
Manufacturer	Allegro MicroSystems, LLC
Package	QSOP-24
Category	Sensors
Pins	24

Electrical characteristics

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

Parameter	Symbol	Min	Typ	Max	Unit	Conditions	Page
Supply Voltage	VCC	3		5.5	V		4
Output Capacitance Load	CLOAD			10	nF	VIOUT pin to GND	4
Output Resistive Load	RLOAD	10			kΩ	VIOUT pin to GND	4
Supply Current	ICC		11	14.5	mA	VIOUT open, FAULT pin high, VCC = 5 V (all versions but -6BB)	4
Full Range Linearity	ELIN	-0.75		0.75	%	IP = ±IP0A	4
Symmetry	ESYM	99.1	100	100.9	%	IP = ±IP0A	4
Setting Voltage for Overcurrent Switch Point	VOC	0.25		0.4	V		4
Signal Noise at Overcurrent Comparator Input	INCOMP	-1		1	A		4
Overcurrent Fault Switch Point Error	EOC	-5		5	%	Switch point in VOC safe operating area; assumes INCOMP = 0 A	4
Overcurrent FAULT Pin Output Voltage	VFAULT			0.4	V	1 mA sink current at FAULT pin	4
Fault Enable (FAULT_EN Pin) Input Low Voltage Threshold	VIL			0.1	V		4
Fault Enable (FAULT_EN Pin) Input High Voltage Threshold	VIH	0.8			V		4
Overcurrent Input Pin Resistance	ROC	2			MΩ	TA = 25°C, VOC pin to GND	5
Voltage Reference Output Load Current (source)	IZCR	3			mA	Source current	5
Voltage Reference Output Load Current (sink)	IZCR	50			µA	Sink current	5
Voltage Reference Output Drift	ΔVZCR	-10		10	mV		5
Optimized Accuracy Range	IP(OA)	-37.5		37.5	A	X35BB (VCC = 5 V)	7
Linear Sensing Range	IP(LIN)	-75		75	A	X35BB (VCC = 5 V)	7
Sensitivity	Sens	27		29.5	mV/A	IP = 25 A, TA = 25°C to 150°C	7
Electrical Offset Voltage	VOE	-5		5	mV	IP = 0 A, TA = 25°C	7
Electrical Offset Voltage	VOE	-25		25	mV	IP = 0 A, TA = 25°C to 150°C	7
Electrical Offset Voltage	VOE	-40		40	mV	IP = 0 A, TA =, 40°C to 25°C	7
Total Output Error	ETOT	-3		3	%	Tested at IP = 25 A, IP applied for 5 ms, TA = 25°C to 150°C	7
Supply Voltage (absolute maximum)	VCC			8	V		2
Filter Pin Voltage	VFILTER			8	V		2
Analog Output Pin Voltage	VIOUT			32	V		2
Overcurrent Input Pin Voltage	VOC			8	V		2
Overcurrent Fault Pin Voltage	VFAULT			8	V		2
Fault Enable Pin Voltage	VFAULTEN			8	V		2
Voltage Reference Output Pin Voltage	VZCR			8	V		2
DC Reverse Voltage (supply, filter, analog output, overcurrent input, overcurrent fault, fault enable, voltage reference output pins)	VRdcx	-0.5			V		2
Output Current Source	IIOUT(Source)			3	mA		2
Output Current Sink	IIOUT(Sink)			1	mA		2
Operating Ambient Temperature Range L	TA	-40		150	°C	Range L	2
Junction Temperature	TJ(max)			165	°C		2
Storage Temperature	Tstg	-65		170	°C		2
Steady State Package Thermal Resistance	RθJA		21		°C/W	Tested with 30 A DC current, ACS709 demo board in 1 cu. ft. of still air	8

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	copper		1 through 6 IP+ Sensed current copper conduction path pins. Terminals for current being sensed;	3

CAD (KiCad official)

Symbol: ACS709LLFTR-35BB-T
Footprint: Package_SO:QSOP-24_3.9x8.7mm_P0.635mm
3D model: QSOP-24 (KiCad packages3D, STEP)
3D model files: acs709llftr-35bb-t-etched.step / acs709llftr-35bb-t-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); acs709llftr-35bb-t.step / acs709llftr-35bb-t.glb are the bare package body.

Provenance

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

Datasheet: Allegro MicroSystems, LLC datasheet (21 pp, sha256 28234f2ddfd5160e, retrieved 2026-10-31, 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

ACS709LLFTR-35BB-T

Verified ACS709LLFTR-35BB-T

Verification log 1 record

3D Model

Symbol & Footprint

Schematic Symbol

PCB Footprint

Datasheet

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