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A4490EESTR-T

Allegro MicroSystems LLC · Charge Pumps · QFN-20-EP(4x4)

A4490EESTR-T from Allegro MicroSystems LLC, in a QFN-20-EP(4x4). 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 FB1 input Feedback input for REG1, connected to the resistor divider from the VREG1 output (0.8 V target reference).
2 VDD power_in Bias supply for logic; externally supplied range is 3.3 to 5.5 V, recommended from a 3.3 to 5 V regulated output.
3 GND power_in Ground; should be connected externally to PGND.
4 FB2 input Feedback input for REG2, connected to the resistor divider from the VREG2 output.
5 ENB2 input Enable input for REG2, logic input, active high (VIH 2.0 V min, VIL 0.8 V max; input current limited to 1 mA).
6 LX2 passive Switch node for REG2, connected to the inductor and flyback diode.
7 VBB2 power_in Input supply for REG2; must be connected together externally with the other VBBx pins (4.5 to 34 V).
8 CPOR passive Power-on-reset delay adjustment; capacitor to ground sets tPOR = 2.131×10^5 × CPOR.
9 PORZ output Power-on-reset open-drain output, active low (VPORZL max 0.4 V at 1 mA).
10 VCP passive Charge pump reservoir capacitor connection.
11 CP2 passive Charge pump capacitor terminal.
12 CP1 passive Charge pump capacitor terminal.
13 PGND power_in Ground for charge pump circuitry; should be connected externally to GND and to the thermal vias.
14 FB3 input Feedback input for REG3, connected to the resistor divider from the VREG3 output.
15 ENB3 input Enable input for REG3, logic input, active high (VIH 2.0 V min, VIL 0.8 V max; input current limited to 1 mA).
16 LX3 passive Switch node for REG3, connected to the inductor and flyback diode.
17 VBB3 power_in Input supply for REG3; must be connected together externally with the other VBBx pins (4.5 to 34 V).
18 VBB1 power_in Input supply for REG1; must be connected together externally with the other VBBx pins (4.5 to 34 V).
19 LX1 passive Switch node for REG1, connected to the inductor and flyback diode.
20 ENB1 input Enable input for REG1, logic input, active high (VIH 2.0 V min, VIL 0.8 V max; input current limited to 1 mA).
21 PAD power_in Exposed pad for enhanced thermal dissipation; connect to the ground (0 V) plane using thermal vias.

Key specifications

Parameter Value
Manufacturer Allegro MicroSystems LLC
Package QFN-20-EP(4x4)
Category Power Management (PMIC)
Pins 21

Electrical characteristics

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

Parameter Symbol Min Typ Max Unit Conditions Page
Load Supply Voltage (absolute maximum) VBB 36 V 2
LX1, LX2, and LX3 Pins (absolute maximum) VLXn -1 36 V 2
PORZ and VDD Pins (absolute maximum) VIN -0.3 7 V 2
ENBx Pin Input Current (absolute maximum) IENBx 1 mA Driven by a current-limited voltage source 2
Operating Ambient Temperature Range E (absolute maximum) TA -40 85 ºC 2
Maximum Junction Temperature (absolute maximum) TJ(max) 150 ºC 2
Storage Temperature (absolute maximum) Tstg -55 150 ºC 2
Load Supply Voltage (recommended) VBB 4.5 34 V To operate at VBB < 6 V, connect VDD supply to the VBB supply 2
LX1, LX2, and LX3 Pins (recommended) VLXn -0.7 34 V 2
Operating Ambient Temperature (recommended) TA -40 85 ºC 2
Junction Temperature (recommended) TJ -40 125 ºC 2
Package Thermal Resistance RθJA 37 ºC/W On 4-layer PCB based on JEDEC standard 2
VBB Quiescent Current IBBON 1 2 mA ENBx = high, ILOAD = 0 mA, VBB = 12 V, current drawn by feedback resistors ignored 5
VDD Supply Range VDD 3.3 5.5 V 5
VDD Quiescent Current (ENBx high) IDD 6 mA ENBx = high 5
Feedback Input Bias Current IBIAS -400 -100 100 nA 5
Feedback Voltage VFB -1.5 1.5 % With respect to 0.8 V target voltage 5
Output Voltage Regulation VOUT -2.5 2.5 % VREGx = 5 V, IOUT = 0 to 1.5 A, TA = -20°C to 85°C 5
Output Voltage Regulation VOUT -3.5 3.5 % VREGx = 5 V, IOUT = 0 to 1.5 A, TA = -40°C to 85°C 5
PWM Frequency fSW 470 550 630 kHz 5
Maximum Duty Cycle Dmax 90 % 5
Current Limit Threshold ILIM 2 A Peak current through switch with D = 0.9 5
Soft Start Duration tss 0.625 1.25 1.875 ms 5
ENBx Input Voltage Low VIL 0.8 V 5
ENBx Input Voltage High VIH 2 V 5
ENBx Input Hysteresis VI(hys) 300 500 mV 5
ENBx Input Current IIL -1 1 μA VIH ≤ 5 V 5
PORZ Output Low Voltage VPORZL 0.4 V IPORZL = 1 mA, fault asserted 5
PORZ Output Leakage Current IPORZH -1 1 μA VPORZ = 5 V, fault not asserted 5
Power-On Reset Duration tPOR 75 115 155 ms CPOR = 470 nF 5
VBB Undervoltage Lockout Startup (no external VDD) VBBUV(su) 3.7 4.3 4.7 V No external VDD supply, VBB rising 6
VBB Undervoltage Lockout Startup (external VDD) VBBCPUV(su) 3.8 4.2 4.6 V External VDD supply, VBB rising 6
VBB Undervoltage Lockout Shutdown (no external VDD) VBBUV(sd) 3.6 4.1 4.7 V No external VDD supply, VBB falling 6
VBB Undervoltage Lockout Shutdown (external VDD) VBBCPUV(sd) 3 3.5 4.3 V External VDD supply, VBB falling 6

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 dissipation. It is lead (Pb) free, with 100% matte tin leadframe plating. 2

CAD (KiCad official)

  • Symbol: A4490EESTR-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: a4490eestr-t-etched.step / a4490eestr-t-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); a4490eestr-t.step / a4490eestr-t.glb are the bare package body.

Provenance

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

  • Datasheet: Allegro MicroSystems LLC datasheet (17 pp, sha256 df57216978689102, retrieved 2026-10-18, 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