This paper presents a low power multi-channel chirp-UWB (C-UWB) transmitter for short range communication systems. The C-UWB transmitter generates a wideband FM signal with a steep spectral roll-off, while enabling a duty-cycled operation. To achieve an optimum duty-cycle control, burst-mode transmission and steep digital gradient generation techniques are employed. A 5-to-9GHz C-UWB transmitter is implemented in 65nm CMOS for multi-channel operation with a channel bandwidth of 500MHz. The transmitter achieves 1Mb/s data rate, consuming 0.5mW from a 1V supply.