Linear Technology LTC1069-6 Datasheet

FEATURES

LTC1069-6

Single Supply, Very Low

Power, Elliptic Lowpass Filter

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DESCRIPTION

■

8th Order Elliptic Filter in SO-8 Package

■

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

f

CUTOFF

: 14kHz (Max)

S/N Ratio: 72dB

■

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

f

CUTOFF

: 20kHz (Max)

S/N Ratio: 79dB

■

±0.1dB Passband Ripple Up to 0.9f

■

42dB Attenuation at 1.3f

■

66dB Attenuation at 2.0f

■

70dB Attenuation at 2.1f

■

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

CUTOFF
CUTOFF
CUTOFF

CUTOFF

(Typ)

Under Single 5V Operation

■

Wideband Noise: 120µV

■

Clock-to-f

■

Internal Sample Rate: 100:1

CUTOFF

Ratio: 50:1

RMS

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APPLICATIONS

■

Handheld Instruments

■

Telecommunication Filters

■

Antialiasing Filters

■

Smoothing Filters

■

Audio

■

Multimedia

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.

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
The gain at f

is –0.7dB. The transition band of the

CUTOFF

CUTOFF

.

LTC1069-6 features progressive attenuation reaching 42dB
at 1.3f

and 70dB at 2.1f

CUTOFF

. The maximum

CUTOFF

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

, the Signal-to-(Noise

RMS

+ THD) ratio is ≥70dB. The wideband noise of the
LTC1069-6 is 125µV

RMS

.

Other filter responses with higher speed can be obtained.
Please contact LTC Marketing for details.

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

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

TYPICAL APPLICATION

Single 3V Supply 10kHz Elliptic Lowpass Filter

0.47µF

0.1µF

AGND

3V

+

V

NC

V

IN

LTC1069-6

V

OUT

–

V

NC

CLK

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f

CLK

= 500kHz

1069-6 TA01

10

0

–10

–20

–30

–40

GAIN (dB)

–50

–60

–70

–80

5

Frequency Response

VIN = 500mV

RMS

10 20 25

15

FREQUENCY (kHz)

1069-6 TA02

1

LTC1069-6

1

2

3

4

8

7

6

5

TOP VIEW

V

OUT



V

–


NC
CLK

AGND

V

+



NC

V

IN

S8 PACKAGE

8-LEAD PLASTIC SO

WW

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ABSOLUTE MAXIMUM RATINGS

Total Supply Voltage (V+ to V–) .............................. 12V

Operating Temperature Range

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PACKAGE/ORDER INFORMATION

ORDER PART

NUMBER

LTC1069-6C ............................................ 0°C to 70°C

LTC1069-6I ........................................ – 40°C to 85°C

Storage Temperature ............................ – 65°C to 150°C

LTC1069-6CS8
LTC1069-6IS8

Lead Temperature (Soldering, 10 sec).................. 300°C

S8 PART MARKING

T

= 125°C, θJA = 110°C/ W

JMAX

Consult factory for Military grade parts.

10696
10696I

ELECTRICAL CHARACTERISTICS

f

is the filter’s cutoff frequency and is equal to f

CUTOFF

/50. The f

CLK

signal level is TTL or CMOS (clock rise or fall time ≤1µs)

CLK

RL = 10k, VS = 5V, TA = 25°C, unless otherwise specified. All AC gains are measured relative to the passband gain.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Passband Gain (fIN ≤ 0.2f

Gain at 0.50f

Gain at 0.75f

Gain at 0.90f

Gain at 0.95f

Gain at f

Gain at 1.30f

CUTOFF

CUTOFF

CUTOFF

CUTOFF

CUTOFF

CUTOFF

)V

CUTOFF

= 5V, f

S

f

TEST

VS = 3V, f
f

TEST

VS = 5V, f
f

TEST

VS = 3V, f
f

TEST

VS = 5V, f
f

TEST

VS = 3V, f
f

TEST

VS = 5V, f
f

TEST

VS = 3V, f
f

TEST

VS = 5V, f
f

TEST

VS = 3V, f
f

TEST

VS = 5V, f
f

TEST

VS = 3V, f
f

TEST

VS = 5V, f
f

TEST

VS = 3V, f
f

TEST

= 200kHz –0.25 0.1 0.45 dB

CLK

= 0.25kHz, VIN = 1V

= 200kHz –0.25 0.1 0.45 dB

CLK

= 0.25kHz, VIN = 0.5V

= 200kHz –0.10 0.07 0.25 dB

CLK

= 2.0kHz, VIN = 1V

= 200kHz –0.15 0.07 0.25 dB

CLK

= 2.0kHz, VIN = 0.5V

= 200kHz –0.25 0 0.25 dB

CLK

= 3.0kHz, VIN = 1V

= 200kHz –0.25 0 0.25 dB

CLK

= 3.0kHz, VIN = 0.5V

= 200kHz –0.25 0.1 0.45 dB

CLK

= 3.6kHz, VIN = 1V

= 200kHz –0.25 0.1 0.45 dB

CLK

= 3.6kHz, VIN = 0.5V

= 200kHz –0.35 0.05 0.25 dB

CLK

= 3.8kHz, VIN = 1V

= 200kHz –0.45 0.05 0.25 dB

CLK

= 3.8kHz, VIN = 0.5V

= 200kHz –1.50 –0.07 –0.20 dB

CLK

= 4.0kHz, VIN = 1V

= 200kHz –1.5 –0.07 0 dB

CLK

= 4.0kHz, VIN = 0.5V

= 200kHz –42 – 40 dB

CLK

= 5.2kHz, VIN = 1V

= 200kHz –41 – 38 dB

CLK

= 5.2kHz, VIN = 0.5V

RMS

RMS

RMS

RMS

RMS

RMS

RMS

RMS

RMS

RMS

RMS

RMS

RMS

RMS

● –0.30 0.1 0.50 dB

● –0.30 0.1 0.50 dB

● –0.15 0.07 0.30 dB

● –0.20 0.07 0.30 dB

● –0.30 0 0.30 dB

● –0.30 0 0.30 dB

● –0.25 0.1 0.45 dB

● –0.30 0.1 0.50 dB

● –0.45 0.05 0.25 dB

● –0.55 0.05 0.35 dB

● –1.65 –0.07 –0.25 dB

● –1.7 –0.07 0 dB

● –42 –39 dB

● –41 – 37 dB

2

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LTC1069-6

FREQUENCY (kHz)

20

–80

GAIN (dB)

–78

–74

–72

–70

–60

–66

40

60

1069-6 G03

–76

–64

–62

–68

80

100

VS = SINGLE 3V
f

CLK

= 500kHz

f

CUTOFF

= 10kHz

V

IN

= 0.5V

RMS

ELECTRICAL CHARACTERISTICS

f

is the filter’s cutoff frequency and is equal to f

CUTOFF

RL = 10k, VS = 5V, TA = 25°C, unless otherwise specified. All AC gains are measured relative to the passband gain.

PARAMETER CONDITIONS MIN TYP MAX UNITS

Gain at 2.00f

Gain at 0.95f

CUTOFF

CUTOFF

Output DC Offset (Note 1) VS = 5V, f

Output DC Offset Tempco VS = 5V, VS = 3V 30 µV/°C
Output Voltage Swing (Note 2) VS = 5V, f

Power Supply Current VS = 5V, f

Maximum Clock Frequency VS = 5V 1.0 MHz

Input Frequency Range 0 <(f
Input Resistance 35 50 80 kΩ
Operating Supply Voltage (Note 3) 310V

VS = 5V, f

= 8.0kHz, VIN = 1V

f

TEST

VS = 3V, f

= 8.0kHz, VIN = 0.5V

f

TEST

VS = 5V, f

= 3V, f

V

S

= 3V, f

V

S

VS = 3V, f

VS = 3V, f

= 3V 0.7 MHz

V

S

/50. The f

CLK

= 200kHz –66 –61 dB

CLK

RMS

= 200kHz –66 –60 dB

CLK

= 400kHz, f

CLK

= 400kHz, f

CLK

= 100kHz 50 175 mV

CLK

= 100kHz 30 135 mV

CLK

= 100kHz 3.4 4.2 V

CLK

= 100kHz 1.6 2.0 V

CLK

= 100kHz 1.2 1.60 mA

CLK

= 100kHz 1.0 1.40 mA

CLK

signal level is TTL or CMOS (clock rise or fall time ≤1µs)

CLK

● –66 –60 dB

RMS

= 7.6kHz, VIN = 1V

TEST

= 7.6kHz, VIN = 0.5V

TEST

RMS

RMS

● –66 –59 dB

–0.5 0.15 0.5 dB
–0.5 0 0.5 dB

● 3.2 4.2 V

● 1.5 2.0 V

● 1.65 mA

● 1.55 mA

CLK

– 2fC)

P-P
P-P

P-P
P-P

The ● denotes specifications which apply over the full operating
temperature range.

Note 1: The input offset voltage is measured with respect to AGND (Pin 1).
The input (Pin 4) is also shorted to the AGND pin. The analog ground pin
potential is internally set to (0.437)(V

SUPPLY

).

Note 2: The input voltage can swing to either rail (V+ or ground); the
output typically swings 50mV from ground and 0.8V from V

Note 3: The LTC1069-6 is optimized for 3V and 5V operation. Although the
device can operate with a single 10V supply or ±5V, the total harmonic
distortion will be degraded. For single 10V or ±5V supply operation we
recommend to use the LTC1069-1.

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TYPICAL PERFORMANCE CHARACTERISTICS

Transition Band Gain vs Frequency

10

0
–10
–20
–30
–40

GAIN (dB)

–50
–60
–70
–80
–90

12

10

FREQUENCY (kHz)

16

14

2

1

0

GAIN (dB)

–1

–2

Passband Gain vs Frequency

VS = SINGLE 3V

= 500kHz

f

CLK

= 10kHz

f

CUTOFF

= 0.5V

V

IN

RMS

3

1

FREQUENCY (kHz)

7

5

9

11

1069-6 G01

VS = SINGLE 3V

= 500kHz

f

CLK

= 10kHz

f

CUTOFF

= 0.5V

V

IN

RMS

18

1069-6 G02

+

.

Stopband Gain vs Frequency

20

3