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LM2577SX-ADJ

Texas Instruments · DC-DC Converters · TO-263-5

LM2577SX-ADJ from Texas Instruments, in a TO-263-5. 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 COMP passive Error amplifier output (compensation) pin where the RC/CC network connects; CC of at least 0.22 µF is required for soft start.
2 FEEDBACK input Error amplifier input that senses the output divider and is compared against the 1.230V internal reference (VOUT = 1.23V(1 + R1/R2)).
3 GND power_in Ground pin, also connected to the package tab.
4 SWITCH output Collector of the internal NPN output switch, rated 3.0A operating current and 0V to 60V operating switch voltage.
5 VIN power_in Input supply pin with operating range 3.5V to 40V (45V absolute maximum), to be bypassed to ground with a 0.1 µF capacitor.
6 EP passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package TO-263-5
Category Power Management ICs
Pins 6

Electrical characteristics

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

Parameter Symbol Min Typ Max Unit Conditions Page
Output Voltage VOUT 11.6 12 12.4 V VIN = 5V to 10V, ILOAD = 100 mA to 800 mA (Figure 31 circuit) 7
Line Regulation ΔVOUT/ΔVIN 20 50 mV VIN = 3.5V to 10V, ILOAD = 300 mA 7
Load Regulation ΔVOUT/ΔILOAD 20 50 mV VIN = 5V, ILOAD = 100 mA to 800 mA 7
Efficiency η 80 % VIN = 5V, ILOAD = 800 mA 7
Input Supply Current (switch off) IS 7.5 10 mA VFEEDBACK = 1.5V (Switch Off) 7
Input Supply Current (switch on) IS 25 50 mA ISWITCH = 2.0A, VCOMP = 2.0V (Max Duty Cycle) 7
Input Supply Undervoltage Lockout VUV 2.7 2.9 3.1 V ISWITCH = 100 mA 7
Oscillator Frequency fO 48 52 56 kHz Measured at Switch Pin, ISWITCH = 100 mA 7
Reference Voltage VREF 1.214 1.23 1.246 V Measured at Feedback Pin, VIN = 3.5V to 40V, VCOMP = 1.0V 7
Reference Voltage Line Regulation ΔVREF/ΔVIN 0.5 mV VIN = 3.5V to 40V 7
Error Amp Input Bias Current IB 100 300 nA VCOMP = 1.0V 7
Error Amp Transconductance GM 2400 3700 4800 μmho ICOMP = −30 μA to +30 μA, VCOMP = 1.0V 7
Error Amp Voltage Gain AVOL 500 800 V/V VCOMP = 1.1V to 1.9V, RCOMP = 1.0 MΩ 7
Error Amplifier Output Swing Upper Limit 2.2 2.4 V VFEEDBACK = 1.0V 7
Error Amplifier Output Swing Lower Limit 0.3 0.4 V VFEEDBACK = 1.5V 7
Error Amp Output Current 130 200 300 μA VFEEDBACK = 1.0V to 1.5V, VCOMP = 1.0V; printed ± 8
Soft Start Current ISS 2.5 5 7.5 μA VFEEDBACK = 1.0V, VCOMP = 0V 8
Maximum Duty Cycle D 93 95 % VCOMP = 1.5V, ISWITCH = 100 mA 8
Switch Transconductance ΔISWITCH/ΔVCOMP 12.5 A/V 8
Switch Leakage Current IL 10 300 μA VSWITCH = 65V, VFEEDBACK = 1.5V (Switch Off) 8
Switch Saturation Voltage VSAT 0.5 0.7 V ISWITCH = 2.0A, VCOMP = 2.0V (Max Duty Cycle) 8
NPN Switch Current Limit 3.7 4.3 5.3 A VCOMP = 2.0V 8
Supply Voltage 45 V 3
Output Switch Voltage 65 V 3
Output Switch Current 6 A must be externally limited when used as step-up regulator 3
Storage Temperature Range -65 150 °C 3
Lead Temperature 260 °C Soldering, 10 sec. 3
Maximum Junction Temperature 150 °C 3
Minimum ESD Rating 2 kV C = 100 pF, R = 1.5 kΩ 3
Supply Voltage VIN 3.5 40 V Operating Ratings 3
Output Switch Voltage VSWITCH 0 60 V Operating Ratings 3
Output Switch Current ISWITCH 3 A Operating Ratings 3
Junction Temperature Range TJ -40 125 °C LM2577 3
Thermal Resistance Junction to Ambient θJA 37 °C/W S Package (DDPAK/TO-263), 1 square inch copper 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 (6) Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads. Additional copper 8

CAD (KiCad official)

  • Symbol: LM2577SX-ADJ
  • Footprint: Package_TO_SOT_SMD:TO-263-5_TabPin6
  • 3D model: TO-263-5 (KiCad packages3D, STEP)
  • 3D model files: lm2577sx-adj-etched.step / lm2577sx-adj-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lm2577sx-adj.step / lm2577sx-adj.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (40 pp, sha256 5eafda8ce16a4e6f, retrieved 2026-10-26, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (text+vision), consensus claude-opus-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