An improved Nauta transconductor, with output resistance for differential-mode output signals insensitive to process and tuning voltage variations, is presented in this paper. Comparing with the classical Nauta transconductor, the proposed transconductor introduces 4 auxiliary inverters only. It can increase the differential-mode output resistance, and keep the common-mode output resistance nearly no changed at the same time. The proposed transconductor has been implemented in a 7th-order transconductance-C (gm-C) band-pass filter (BPF) in a standard 0.18-μm CMOS technology. The proposed filter has achieved a bandwidth of 20 MHz under a 15-MHz center frequency. Monte Carlo simulation results show that with the same tuning voltage range, the gain deviation of the filter with proposed transconductors is reduced 4.4 dB comparing with the counterpart based on classical Nauta transconductors, and the sensitivity of the quality (Q) factor of filter poles to tuning voltage is also significantly reduced. Measurement results show that the pass-band ripple of the proposed filter is reduced 1 dB, and the stop-band attenuation is reduced 8 dB at 30 MHz.