A new, high-performance log detector from Linear Technology offers high sensitivity, allowing more accurate measurement of lower levels of RF and IF signals. The LT5537 has a wide operating frequency range from near dc to 1 GHz. It features a measurement dynamic range of 90 dB, enabling wide operating range for receivers in such applications as automatic gain control (AGC) loops. Additionally, the device offers exceptional accuracy over temperature, making it suitable for wireless base stations, access points, subscriber radios, and RF instrumentation subject to a wide range of environmental conditions.

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It incorporates a cascading chain of limiting amplifiers to provide a constant, linear 20 mV/dB logarithmic detection function. Additionally, the device incorporates on-chip compensation circuitry to yield an accurate and stable output under varying temperature environments. The device can measure signals within an error of ±1 dB over the worst-case temperature extremes. Moreover, the device has superior sensitivity, capable of detecting RF signal levels as low as –82 dBm. On the high side, the device can measure up to +12 dBm input levels. The LT5537 operates from a single supply voltage ranging from 2.7 V to 5.25 V. Typical operating current is 13.5 mA. The device can be shut down by applying an external 0 V into an ENBL pin. When disabled, the chip typically draws 500 uA quiescent current to conserve power. The LT5537 is offered in an 8-lead 3 mm x 2 mm surface-mount DFN package. The device requires fewer external components than alternative solutions, providing a compact, cost-effective solution. It is priced at $2.95 each in 1000-piece quantities and is available from stock.