May 15, 2012 – Linear Technology Korea (CEO Hong Sa-gwak) announced the development of the LTC5584, an ultra-wideband direct conversion I/Q demodulator with exceptional linearity of 31dBm IIP3 and 70dBm IIP2. This device offers industry-leading 530MHz demodulation bandwidth, supporting the latest LTE multimode, LTE Advanced receivers, and digital predistortion (DPD) receivers. The I/Q demodulator operates across a wide frequency range of 30MHz to 1.4GHz, covering a broad range of VHF and UHF wireless applications as well as 450MHz/700MHz LTE frequency bands.
A unique feature of the LTC5584 is the incorporation of two built-in calibration functions. One is an advanced circuit that allows system designers to optimize the receiver's IIP2 performance, pushing it from 70dBm to over 80dBm. The other is an on-chip circuit that nulls out DC offset voltage at the I/Q outputs. With a 9.9dB noise figure characteristic and these features, dynamic range performance in receivers can be enhanced. Moreover, with a P1dB of 12.6dBm and a noise figure of 13.6dB under 0dBm in-band blocker conditions, this product ensures robust receiver performance even in interference-prone environments.
The LTC5584 offers increased flexibility for use in low-IF receiver applications, providing very low I/Q amplitude and phase mismatch. Amplitude mismatch is typically 0.02dB, while phase error is typically 0.25 degrees (both at 450MHz). This delivers a receiver image rejection ratio of 52dB.
With broad bandwidth capability, the LTC5584 is ideal for multimode LTE and CDMA DPD receivers as well as other wideband receiver applications. It is particularly well-suited for DPD, and modern base stations require demodulation bandwidth exceeding 300MHz. The LTC5584 not only surpasses these bandwidth requirements but also provides conversion gain flatness of ±0.5dB or less. Beyond wireless infrastructure applications, the LTC5584 is ideally utilized in military receivers, broadband communications, P2P microwave data links, image rejection receivers, and long-range RFID readers.
The LTC5584 is offered in a 24-pin 4mm x 4mm QFN package. This device operates over a case temperature range of -40°C to 105°C. Utilizing a single 5V supply voltage, the LTC5584 consumes a total supply current of 200mA. The device uses digital input to enable or disable the chip. When disabled, leakage current is typically 11μA. With turn-on time of 200ns and turn-off time of 800ns, this demodulator is fast enough for use in burst mode receivers.
The LTC5584 starts at $5.65 per unit based on 1,000-unit quantities and is currently in volume production. For detailed product information, refer to www.linear.com/product/LTC5584.

Photo Caption: 30MHz ~ 1.4GHz Wideband High Linearity I/Q Demodulator

Product Features: LTC5584