Overview

The IR2103 (and its modern lead-free counterpart IRS2103PBF / IRS2103STRPBF) is a high-voltage, high-speed half-bridge power MOSFET and IGBT gate driver IC manufactured by Infineon Technologies (originally International Rectifier). It provides independent high- and low-side referenced output channels designed to drive two N-channel power MOSFETs or IGBTs in half-bridge, synchronous buck, full-bridge inverter, and BLDC motor drive topologies.

The high-side driver features a floating bootstrap channel capable of operating up to $+600\text{V}$ relative to ground ($COM$), with high immune $dV/dt$ noise tolerance ($50\text{ V/ns}$). The IC incorporates internal cross-conduction prevention logic and matched propagation delays ($520\text{ ns}$ typical internal deadtime) to prevent catastrophic shoot-through current during switching.

Quick reference

Pinout (DIP-8 / SOIC-8 Package)

        ┌──────────────┐
    VCC ─│ 1          8 │─ VB
    HIN ─│ 2          7 │─ HO
  ~LIN~ ─│ 3          6 │─ VS
    COM ─│ 4          5 │─ LO
        └──────────────┘

Input / Output Logic Truth Table

The low-side input (~LIN~) is active-LOW, making complementary driving with a single MCU PWM pin straightforward:

Standard Half-Bridge Application Circuit

                      +V_BUS High Voltage (Up to 600V DC)
                         │
                         ├───────────┐ [D_BOOT Ultra-Fast]
                         │           │
                         │          ┌┴┐
                         │          │▲│
                         │          └┬┘
                         │           │
                     [Pin 1: VCC]    │
                       IR2103        │
                     [Pin 8: VB] ────┴──────┐
                         │                  │
                     [Pin 7: HO] ─[R_G1]─┐ [C_BOOT 0.1µF-1.0µF]
                         │               │  │
                         │             ┌─┴──┴─┐  [Q1 High-Side N-MOSFET]
                     [Pin 6: VS] ──────┤  S   │
                         │             └──┬───┘
                         │                ├──────────── Output / Motor / Inductor
                         │                │
                     [Pin 5: LO] ─[R_G2]─┐│
                         │               ││
                         │             ┌─┴┴───┐  [Q2 Low-Side N-MOSFET]
                     [Pin 4: COM] ─────┤  S   │
                         │             └──┬───┘
                        GND               │
                                         GND

• Bootstrap Diode ($D_{BOOT}$): Must be an ultra-fast recovery diode (such as UF4007 or ES1J) rated for the full high-voltage bus ($V_{BUS} + 20\%$).
• Bootstrap Capacitor ($C_{BOOT}$): Low-ESR ceramic capacitor ($0.1\ \mu\text{F} \dots 1.0\ \mu\text{F}$, $\ge 25\text{V}$) charged when LO is active and $V_S$ is pulled to ground.

Specifications

Common mistakes

• Forgetting that ~LIN~ is inverted: Unlike drivers with active-high inputs on both channels (like IR2101), the IR2103 requires ~LIN~ to be driven LOW to turn on the low-side gate (LO). If connected to a standard active-high MCU pin without inverting logic, the low-side switch will remain continuously ON.
• Operating at 100% High-Side Duty Cycle: The floating bootstrap capacitor ($C_{BOOT}$) charges only when the switching node ($V_S$) is grounded by the low-side MOSFET. Continuous DC high-side conduction without periodic low-side switching causes the bootstrap capacitor to discharge, causing high-side gate drive failure via undervoltage lockout.
• Using a standard rectifier diode for bootstrap: A slow 1N4007 diode cannot reverse-recover fast enough during high-frequency switching ($> 20\text{ kHz}$), leading to massive reverse recovery current into the $V_{CC}$ rail and diode destruction. Always use an ultra-fast recovery diode ($t_{rr} < 75\text{ ns}$) like UF4007 or MUR120.
• Negative voltage transients on VS: Inductive switching can pull $V_S$ below $COM$ ground ($< -5\text{V}$), which can latch up the internal CMOS substrate. Add a low-forward-drop Schottky diode from $COM$ to $V_S$ and a small resistor ($3\ \Omega \dots 10\ \Omega$) in series with $V_S$.

Notes

• Drop-in Sibling (IR2104): The IR2104 uses the same 8-pin package but features a single input (IN) and an active-low shutdown (~SD~) pin instead of split HIN / ~LIN~ inputs.