Apparatus and methods for a delay circuit are provided. In an example, a delay circuit can include a resistor configured to receive a compensation current, a capacitor configured to receive a charge current based on the compensation current, a first compensation circuit configured to provide a control signal, and a charge-current coupling circuit. The first compensation circuit can include an inverter circuit configured to track an inverter threshold voltage across process, voltage and temperature variations, wherein an output of the inverter circuit is directly coupled to an input of the inverter circuit, and an amplifier configured to receive the output of the inverter circuit an provide the control signal. The charge-current coupling circuit can be configured to receive the control signal and to provide the compensation current and the charge current.