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Basestations profit from ADC that provides direct IF sampling up to 500MHz

Milpitas, CA — March 16, 2004 — A new 80 Msps, 14-bit analog to digital converter (ADC) from Linear Technology provides designers of cellular basestations with a dramatic improvement in dynamic performance. The LTC1750 greatly simplifies the design and reduces the cost of cellular basestations by eliminating the second intermediate frequency (IF) down-conversion stage. The device provides wide input bandwidth and excellent dynamic performance for direct IF digitizing applications. The LTC1750 undersamples up to 500MHz input frequencies and delivers 84dB spurious free dynamic range (SFDR) with 140MHz inputs and 74dB SFDR with 350MHz inputs. The device's wide bandwidth and excellent AC performance are ideal for use in cellular basestations and broadband software radios, where it can directly digitize the first IF and eliminate the second IF down-conversion stage.

The LTC1750 offers the flexibility to configure the input and the output specifically for the application. An on-chip programmable gain amplifier (PGA) allows multiple input ranges to optimize the performance. The larger input range offers industry-leading low noise, and the smaller range lowers the gain requirements on the drive circuitry, making it easier to meet the IP3 requirements. If the input ever goes out of range there is automatic indicator on the overflow pin. A separate digital output supply pin allows connection to low voltage DSPs, FIFOs or logic as low as 0.5V.

The LTC1750 is one device in a family of pin compatible high speed ADCs. The LTC1749 is a pin compatible 12-bit version of the LTC1750 allowing multiple price/performance products with one design. For other high-speed applications this pin compatible family extends from 25Msps to 80Msps and from 12-bits to 14-bits. Each device is available in the 48-pin TSSOP package for both the commercial and the industrial temperature ranges.

Pricing for 1,000-piece quantities begins at $32.30 each for the LTC1750, $19.55 each for the LTC1749.

Summary of Features: LTC1749/LTC1750
– LTC1750: 14-Bit 80Msps Wide Bandwidth ADC
– LTC1749: 12-Bit 80Msps Wide Bandwidth ADC
– 500MHz Full Power Bandwidth S/H
– LTC1750 ” 71.7dB SNR & 84dB SFDR @ 140MHz
– Selectable Input Ranges: 1.35Vp-p to 2.25Vp-p
– Output Supply Pin: 0.5V to 5V Range
– Single 5V Supply
– Power Dissipation: 1.45W
– 48-Pin TSSOP Package

For more information, contact
Linear Technology Corporation, 1630 McCarthy Boulevard, Milpitas, CA 95035-7417. Tel: 408-432-1900 1-800-4-LINEAR
or go to: www.linear.com

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