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A 200MHz to 6GHz Direct Conversion I/Q Modulator Achieves 30.9dBm Output Third-Order Intercept

MILPITAS, CA - September 14, 2010 - Linear Technology introduces the LTC5588-1, a new generation ultra-high linearity direct conversion I/Q modulator that operates over a wide frequency range from 200MHz to 6GHz. The new modulator offers best-in-class linearity performance of 30.9dBm OIP3 (Output Third-Order Intercept) at
2.14GHz - without calibration. The device also has the unique capability for simple calibration by a single-pin adjustment with a DC input voltage that further optimizes its OIP3 up to 35.1dBm. The LTC5588-1's linearity performance is complemented with a noise floor of -160.6dBm/Hz at 6MHz offset, enabling transmitters to achieve unprecedented dynamic range performance.

The LTC5588-1 offers image suppression of -56.6dBc at 2.14GHz. In addition, its carrier leakage is -39.6dBm while delivering 5dBm signal power to its output without calibration. Over the operating temperature range from
-40°C to 85°C, both parameters exhibit stable behavior, varying only about +/-3dB. Its performance satisfies the system requirements of the most demanding broadband wireless 4G basestations, including LTE, WiMAX, multi-carrier GSM/EDGE, W-CDMA, TD-SCDMA, CDMA-2000 and CDMA, as well as other high performance wireless applications.

The LTC5588-1's I and Q inputs are biased to a 0.5V DC common-mode voltage that is directly compatible with commercially available D/A converters that have similar DC common-mode voltage. The I and Q inputs support signal bandwidth greater than 400MHz.

The LTC5588-1 is powered from a single 3.3V supply with an operating current of 300mA. The device has an Enable pin, allowing the chip to power down completely. In shutdown mode, the device draws a sleep current of less than 900uA. The modulator has fast turn-on and turn-off time, at 15ns and 5ns, respectively, supporting TDD (Time Division Duplexing) mode of operation. The LTC5588-1 comes in a compact 4mm x 4mm 24-pin QFN package and is available immediately from stock, priced starting at $5.70 each in 1,000 piece quantities. For more information, visit www.linear.com/5588.

Summary of Features: LTC5588-1 Operating Frequency Range 200MHz to 6GH Output IP3 at 900MHz -31.3 dBm at 900MHz (Optimized) 35.1 dBm Output IP3 at 2.14GHz 30.9 dBm at 2.14GHz (Optimized) 35.1 dBm Output IP2 at 2.14GHz 58.5 dBm Easy Single-Pin Calibration To Optimize OIP3 Noise Floor at 6MHz Offset -160dBm/Hz Image Suppression at 2.14GHz -56.6 dBc (uncalibrated) Carrier Leakage (POUT = 5dBm)                      -39.6 dBm Low Power Consumption                    Single 3.3V, 300mA Small Package 4mm x 4mm QFN

200MHz to 6GHz Direct Quadrature Modulator with Ultrahigh OIP3 Click Photo for High-Res Image