Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsLinear ICsLTC 1069-1 CN Case type DIP-8 Type (misc.) L/P 8th Order Progress Elliptic LPF

LTC1069-1

Low Power, 8th Order

Progressive Elliptic,

Lowpass Filter

■

8th Order Elliptic Filter in SO-8 Package

■

Operates from Single 3.3V to ±5V Power Supplies

■

–20dB at 1.2f

CUTOFF

■

–52dB at 1.4f

CUTOFF

■

–70dB at 2f

CUTOFF

■

Wide Dynamic Range

■

110µV

RMS

Wideband Noise

■

3.8mA Supply Current with ±5V Supplies

■

2.5mA Supply Current with Single 5V Supply

■

2mA Supply Current with Single 3.3V Supply

The cutoff frequency (f

CUTOFF

) of the LTC1069-1 is equal

to the clock frequency divided by 100. The gain at f

CUTOFF

is –0.7dB and the typical passband ripple is ±0.15dB

up to 0.9f

CUTOFF

. The stopband attenuation of the

LTC1069-1 features a progressive elliptic response

reaching 20dB attenuation at 1.2f

CUTOFF

, 52dB attenua-

tion at 1.4f

CUTOFF

and 70dB attenuation at 2f

CUTOFF

With ±5V supplies, the LTC1069-1 cutoff frequency can

be clock-tuned up to 12kHz; with a single 5V supply, the

maximum cutoff frequency is 8kHz.

The low power feature of the LTC1069-1 does not penal-

ize the device’s dynamic range. With ±5V supplies and an

input range of 0.3V

RMS

to 2.5V

RMS

, the signal-to-(noise

+ THD) ratio is ≥70dB. The wideband noise of the

LTC1069-1 is 110µV

RMS

Other filter responses with

lower power or higher speed can be obtained. Please

contact LTC marketing for details.

The LTC1069-1 is available in 8-pin PDIP and 8-pin SO

packages.

ITY

Frequency Response

FREQUENCY (kHz)

1.5

–80

GAIN (dB)

–70

–50

–40

–30

4.5

1069-1 TA02

–60

3 7.56

–20

–10

Single 3.3V Supply 3kHz Elliptic Lowpass Filter

1

2

3

8

7

6

OUT



–



NC

CLK

AGND



NC

0.1µF

0.47µF

3.3V



1069-1 TA01

OUT

LTC1069-1

CLK

300kHz

■

Telecommunication Filters

■

Antialiasing Filters

ESCRIPTIO

The LTC

1069-1 is a monolithic 8th order lowpass filter

featuring clock-tunable cutoff frequency and 2.5mA power

supply current with a single 5V supply. An additional

feature of the LTC1069-1 is operation with a single 3.3V

supply.

, LTC and LT are registered trademarks of Linear Technology Corporation.

Summary of content (8 pages)

PAGE 1
LTC1069-1 Low Power, 8th Order Progressive Elliptic, Lowpass Filter FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 8th Order Elliptic Filter in SO-8 Package Operates from Single 3.3V to ±5V Power Supplies – 20dB at 1.2 fCUTOFF – 52dB at 1.4 fCUTOFF – 70dB at 2 fCUTOFF Wide Dynamic Range 110µVRMS Wideband Noise 3.8mA Supply Current with ±5V Supplies 2.5mA Supply Current with Single 5V Supply 2mA Supply Current with Single 3.
PAGE 2
LTC1069-1 U W W W Total Supply Voltage (V + to V –) ............................. 12V Maximum Voltage at Any Pin ............................ (V– – 0.3V) ≤ V ≤ (V+ + 0.3V) Operating Temperature Range LTC1069-1C ........................................... 0°C to 70°C LTC1069-1I ....................................... – 40°C to 85°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................
PAGE 3
LTC1069-1 ELECTRICAL CHARACTERISTICS fCUTOFF is the filter’s cutoff frequency and is equal to fCLK/100. The fCLK signal level is TTL or CMOS (clock rise or fall time ≤ 1µs), VS = 3.3V to ±5V, RL = 10k, TA = 25°C, unless otherwise noted. All AC gains are measured relative to the passband gain. PARAMETER CONDITIONS Gain at 1.50fCUTOFF VS = ±5V, fTEST = 7.5kHz, fCLK = 500kHz VIN = 1VRMS VS = 3.3V, fTEST = 3kHz, fCLK = 200kHz VIN = 0.5VRMS VS = ±5V, VS = 4.75V, VS = 3.
PAGE 4
LTC1069-1 U W TYPICAL PERFORMANCE CHARACTERISTICS Passband Gain vs Clock Frequency, VS = Single 3.3V Passband Gain vs Clock Frequency, VS = Single 5V 2.0 2.0 2.0 VS = SINGLE 3.3V VIN = 0.5VRMS 1.5 1.0 1.0 fCLK = 750kHz fC = 7.5kHz GAIN (dB) 0.5 0 –0.5 fCLK = 500kHz fC = 5kHz –1.0 2.5 1.5 3.5 0.5 4.5 5.5 6.5 7.5 FREQUENCY (kHz) 0 –0.5 fCLK = 500kHz fC = 5kHz fCLK = 500kHz fC = 5kHz –0.5 fCLK = 1MHz fC = 10kHz –1.0 –1.5 –2.0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.
PAGE 5
LTC1069-1 U W TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Swing vs Temperature Supply Current vs Clock Frequency Supply Current vs Supply Voltage 5 5 fCLK = 10Hz 5.0 25°C 3 85°C –40°C 2 1 VS = ±5V 4.0 3.5 VS = 5V 3.0 2.5 VS = 3.3V 3 1 VS = ±1.57V –1 –2 VS = ±2.5V –3 –4 –5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.2 CLOCK FREQUENCY (MHz) 6 VS = ±1.57V 0 2.0 1 3 4 5 2 TOTAL SUPPLY VOLTAGE (±V) VS = ±2.5V 2 0 0 VS = ±5V 4 4.
PAGE 6
LTC1069-1 U U U PIN FUNCTIONS NC (Pins 3, 6): No Connection. Pins 3 and 6 are not connected to any internal circuity; they should be preferably tied to ground. VIN (Pin 4): Filter Input Pin. The filter input pin is internally connected to the inverting input of an op amp through a 43k resistor. CLK (Pin 5): Clock Input Pin. Any TTL or CMOS clock source with a square wave output and 50% duty cycle (±10%) is an adequate clock source for the device.
PAGE 7
LTC1069-1 U U W U APPLICATIONS INFORMATION the input pin (4) shorted to the AGND pin and depends on PC board layout and on the value of the power supplies. With proper layout techniques the values of the clock feedthrough are shown on Table 2. Table 2. Clock Feedthrough VS 3.3V 5V ±5V CLOCK FEEDTHROUGH 10µVRMS 40µVRMS 160µVRMS supply voltage (see Table 3). The clock feedthrough specifications are not part of the wideband noise. Table 3. Wideband Noise VS 3.
PAGE 8
LTC1069-1 U TYPICAL APPLICATIONS Dual Supply Operation –45 fIN = 1kHz –50 AGND 8 VOUT VOUT 2 7 V– V+ LTC1069-1 0.1µF 3 6 NC NC 5V 0.1µF 4 VIN VIN 5 CLK – 5V fCLK 500kHz 5V 0V fC = 5kHz THD + NOISE (dB) –55 1 –60 –65 –70 –75 –80 –85 0.1 1 INPUT VOLTAGE (VRMS) 3 1069-1 TA03 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherswise noted. N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.