LTC1068-25

Features:

Four Identical 2nd Order Filters in an SSOP Package
Maximum Center Frequency up to 200kHz (V_S = ±5V)
Center Frequency Error: ±0.3% (Typ)
Low Noise: £40V_RMS per 2nd Order Section, Q 5
High Dynamic Range: THD + Noise 0.05%
Low DC Offsets: 10mV per 2nd Order Section
Clock-to-Center Frequency Ratio: 25:1
No Aliasing for Input Frequencies up to 50*f_CUTOFF
Operates from ±2.375V to ±5V Power Supplies


Application

High Selectivity Bandpass Filters (40kHz to 140kHz)
Dual 4th Order Lowpass Filters up to 200kHz
Elliptic Lowpass Filters up to 140kHz


Pinout




Specifications

Total Supply Voltage (V⁺ to V ) .............................. 12V
Power Dissipation .................................................... 500mW
Operating Temperature Range
  LTC1068CG-25 ....................................................... 0°C to 70°C
  LTC1068IG-25 ........................................................ 40°C to 85°C
Input Voltage at Any Pin .......................................... V 0.3V  VIN V ⁺ + 0.3V
Storage Temperature Range .................................... 65°C to 150°C
Lead Temperature (Soldering, 10 sec)...................... 300°C


Description

The LTC^®1068-25 consists of four identical, low noise, high accuracy 2nd order switched-capacitor filter building blocks. Each building block, together with three to five resistors, can provide 2nd order filter functions like lowpass, bandpass, highpass and notch. High precision, high performance, quad 2nd order, dual 4th order or 8th order filters can also be designed with an LTC1068-25. The center frequency of each 2nd order section is tuned by an external clock. The clock-to-center frequency ratio is internally set to 25:1 and can be modified by external resistors.

The sampling rate of the LTC1068-25 is twice the clock frequency. The maximum input frequency can approach twice the clock frequency before aliasing occurs.

A customized version of the LTC1068-25 in a 16-lead SO with internal thin film resistors can be obtained. Clock-tocenter frequency ratios higher or lower than 25:1 can also be obtained. Please contact LTC Marketing for details.

The LTC1068-25 is available in a 28-pin SSOP surface mount package and is supported by FilterCAD^TM 2.0 filter design software.