Datasheet

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LTC1069-6

10696fa

TYPICAL APPLICATION

DESCRIPTION

Single Supply, Very Low

Power, Elliptic Lowpass Filter

The LTC

1069-6 is a monolithic low power, 8th order lowpass

ﬁ lter optimized for single 3V or single 5V supply operation.

The LTC1069-6 typically consumes 1mA under single 3V

supply operation and 1.2mA under 5V operation.

The cutoff frequency of the LTC1069-6 is clock tunable and it is

equal to the clock frequency divided by 50. The input signal is

sampled twice per clock cycle to lower the risk of aliasing.

The typical passband ripple is ±0.1dB up to 0.9f

CUTOFF

The gain at f

CUTOFF

is –0.7dB. The transition band of the

LTC1069-6 features progressive attenuation reaching

42dB at 1.3f

CUTOFF

and 70dB at 2.1f

CUTOFF

. The maximum

stopband attenuation is 72dB.

The LTC1069-6 can be clock tuned for cutoff frequencies

up to 20kHz (single 5V supply) and for cutoff frequencies

up to 14kHz (single 3V supply).

The low power feature of the LTC1069-6 does not penalize

the device’s dynamic range. With single 5V supply and

an input range of 0.4V

RMS

to 1.4V

RMS

, the Signal-to-

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

LTC1069-6 is 125μV

RMS

Other ﬁ lter responses with higher speed can be obtained.

Please contact LTC Marketing for details.

The LTC1069-6 is available in an 8-pin SO package.

Single 3V Supply 10kHz Elliptic Lowpass Filter

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

FEATURES

APPLICATIONS

8th Order Elliptic Filter in SO-8 Package

Single 3V Operation: Supply Current: 1mA (Typ)

CUTOFF

: 14kHz (Max) S/N Ratio: 72dB

Single 5V Operation: Supply Current: 1.2mA (Typ)

CUTOFF

: 20kHz (Max) S/N Ratio: 79dB

±0.1dB Passband Ripple Up to 0.9f

CUTOFF

(Typ)

42dB Attenuation at 1.3f

CUTOFF

66dB Attenuation at 2.0f

CUTOFF

70dB Attenuation at 2.1f

CUTOFF

Wide Dynamic Range, 75dB or More (S/N + THD),

Under Single 5V Operation

Wideband Noise: 120µV

RMS

Clock-to-f

CUTOFF

Ratio: 50:1

Internal Sample Rate: 100:1

Handheld Instruments

Telecommunication Filters

Antialiasing Filters

Smoothing Filters

Audio

Multimedia

AGND

OUT

–

CLK

LTC1069-6

CLK

= 500kHz

0.47μF

0.1μF

1069-6 TA01

FREQUENCY (kHz)

–80

GAIN (dB)

–70

–50

–40

–30

1069-6 TA02

–60

10 20 25

–20

–10

= 500mV

RMS

Frequency Response

Summary of content (10 pages)

PAGE 1
LTC1069-6 Single Supply, Very Low Power, Elliptic Lowpass Filter FEATURES DESCRIPTION n The LTC®1069-6 is a monolithic low power, 8th order lowpass ﬁlter optimized for single 3V or single 5V supply operation. The LTC1069-6 typically consumes 1mA under single 3V supply operation and 1.2mA under 5V operation. n n n n n n n n n n 8th Order Elliptic Filter in SO-8 Package Single 3V Operation: Supply Current: 1mA (Typ) fCUTOFF: 14kHz (Max) S/N Ratio: 72dB Single 5V Operation: Supply Current: 1.
PAGE 2
LTC1069-6 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION Total Supply Voltage (V + to V –) ................................12V Operating Temperature Range LTC1069-6C ............................................. 0°C to 70°C LTC1069-6I ..........................................– 40°C to 85°C Storage Temperature..............................– 65°C to 150°C Lead Temperature (Soldering, 10 sec) ..................
PAGE 3
LTC1069-6 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range. fCUTOFF is the filter’s cutoff frequency and is equal to fCLK/50. The fCLK signal level is TTL or CMOS (clock rise or fall time ≤ 1µs) RL = 10k, VS = 5V, TA = 25°C, unless otherwise specified. All AC gains are measured relative to the passband gain. SYMBOL CONDITIONS Gain at fCUTOFF VS = 5V, fCLK = 200kHz fTEST = 4.0kHz, VIN = 1VRMS Gain at 1.30fCUTOFF Gain at 2.
PAGE 4
LTC1069-6 TYPICAL PERFORMANCE CHARACTERISTICS Transition Band Gain vs Frequency Passband Gain vs Frequency 2 VS = SINGLE 3V fCLK = 500kHz fCUTOFF = 10kHz VIN = 0.5VRMS 1 VS = SINGLE 3V fCLK = 500kHz fCUTOFF = 10kHz VIN = 0.
PAGE 5
LTC1069-6 TYPICAL PERFORMANCE CHARACTERISTICS Dynamic Range THD + Noise vs Input/Output Voltage Dynamic Range THD + Noise vs Input Voltage VIN = 2.945VP-P –55 THD + NOISE (dB) THD + NOISE (dB) fCLK = 170kHz –45 fCUTOFF = 3.4kHz f = 1kHz –50 IN –60 –65 –70 –75 THD + Noise vs Frequency –40 –40 fCLK = 500kHz –45 fIN = 1kHz fCLK = 500kHz –45 fCUTOFF = 10kHz –50 –50 –55 THD + NOISE (dB) –40 VS = SINGLE 3V –60 VS = SINGLE 5V –65 –70 –75 –55 –65 –70 –75 –80 –80 –85 –85 –85 –90 0.
PAGE 6
LTC1069-6 PIN FUNCTIONS for single supply operation, the internal biasing of Pin 1 allows optimum output swing. The AGND pin should be buffered if used to bias other ICs. Figure 2 shows the connections for single supply operation. 1 0.47μF V+ 2 AGND V+ 0.1μF 3 4 VIN VOUT V– LTC1069-6 NC NC VIN CLK 8 VOUT 7 6 5 ANALOG GROUND PLANE STAR SYSTEM GROUND DIGITAL GROUND PLANE 1k CLOCK SOURCE 1069-6 F02 Figure 2. Connections for Single Supply Operation V +, V – (Pins 2, 7): Power Supply Pins.
PAGE 7
LTC1069-6 APPLICATIONS INFORMATION Temperature Behavior 2 VS = SINGLE 3V VIN = 0.5VRMS 1 GAIN (dB) The power supply current of the LTC1069-6 has a positive temperature coefﬁcient. The GBW product of its internal op amps is nearly constant and the speed of the device does not degrade at high temperatures. Figures 4a, 4b and 4c show the behavior of the passband of the device for various supplies and temperatures. The ﬁlter has a passband behavior which is temperature independent.
PAGE 8
LTC1069-6 APPLICATIONS INFORMATION Wideband Noise Aliasing The wideband noise of the ﬁlter is the total RMS value of the device’s noise spectral density and determines the operating signal-to-noise ratio. The frequency contents of the wideband noise lie within the ﬁlter’s passband. The wideband noise cannot be reduced by adding post ﬁltering. The total wideband noise is nearly independent of the clock frequency and depends slightly on the power supply voltage (see Table 3).
PAGE 9
LTC1069-6 PACKAGE DESCRIPTION S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 .050 BSC 8 .245 MIN 7 6 5 .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 s 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 0°– 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN .053 – .069 (1.346 – 1.752) .014 – .019 (0.355 – 0.
PAGE 10
LTC1069-6 TYPICAL APPLICATION Single 5V Operation with Power Shutdown 5V ON SHUTDOWN 1 AGND 2 0.47μF 8 VOUT VOUT 7 V– V+ LTC1069-6 3 6 NC NC 0.1μF VIN 4 VIN 5 CLK fCLK ≤ 750kHz 5V 0V 1069-6 TA03 Single 3V Supply Operation with Output Buffer 3.3V 0.1μF 8 5 7 V– V+ LTC1069-6 3 6 NC NC 6 1 0.47μF AGND VOUT 2 0.1μF 4 VIN VIN CLK 5 + 8 7 1/2 LT1366 fCLK 500kHz – 3.