This paper presents a high dynamic range variable gain amplifier (VGA) using 130 nm CMOS technology for the triple-band W-CDMA applications. The VGA includes an active balun, a two-stage amplifier, two SPDT switches, and a V-I converter which converts a dc control voltage to the dc current for controlling the gain of the each amplifier. The operation voltage is 2.5 V. The dynamic range is over 100 dB at 800 MHz-band and 84 dB at 2 GHz-band. To realize high dynamic range with the two-stage amplifier, a novel exponential approximation function for V-I converter is proposed. The maximum output power at 800 MHz is 7 dBm with a gain of 27 dB. At this rated output power, the adjacent channel power rejection (ACPR) in +/-5 MHz offset frequency bands are -43 dBc which is highly linear performance.