Micro Linear Corporation ML2111CCS, ML2111CIP, ML2111CCP Datasheet

May 1997

ML2111*

Universal Dual High Frequency Filter

GENERAL DESCRIPTION

The ML2111 consists of two independent switched capacitor filters that operate at up to 150kHz and perform second order filter functions such as lowpass, bandpass, highpass, notch and allpass. All filter configurations, including Butterworth, Bessel, Cauer, and Chebyshev can be formed.

The center frequency of these filters is tuned by an external clock or the external clock and resistor ratio.

The ML2111 frequency range is specified up to 150kHz with ±5.0V ±10% power supplies. Using a single 5.0V ±10% power supply the frequency range is up to 100kHz. These filters are ideal where center frequency accuracy and high Qs are needed.

The ML2111 is a pin compatible superior replacement for MF10, LMF100, and LTC1060 filters.

BLOCK DIAGRAM

FEATURES

■ Specified for operation up to 150kHz

■ Center frequency x Q product £ 5MHz

■ Separate highpass, notch, allpass, bandpass, and

lowpass outputs

■ Center frequency accuracy of ±0.4% or ±0.8% max.

■ Q accuracy of ±4% or ±8% max.

■ Clock inputs are TTL or CMOS compatible

■ Single 5V (±2.25V) or ±5V supply operation

* Some Packages Are End Of Life and Obsolete

INV

4

AGND

15

CLK

10

50/100HOLD

12

LEVEL SHIFT

9

CLK

11

INV

17

7

V

A

B

A+

LEVEL SHIFT

V

A-

14

8

V

D+

NON-OVERLAP

V

D-

13

N/AP/HP

-

+

CLOCK

CONTROL

CLOCK

-

+

N/AP/HP

3

A

B

5

S1

A

-

+

Σ

-

+

Σ

S1

1618

∫ ∫

S2

A

S2

B

∫ ∫

B

2

BP

A

BP

B

19

1

LP

A

S

A/B

6

LP

B

20

1

ML2111

PIN CONFIGURATION

ML2111 20-Pin PDIP (P20) 20-Pin SOIC (S20)

PIN DESCRIPTION

PIN NAME FUNCTION

1LP

A

Lowpass output for biquad A.

LP

BP

N/AP/HP

INV

S1

S

A/B

V

CLK

A

A+

D+

LSh

A

1

2

3

4

5

6

7

8

9

10

TOP VIEW

LP

20

B

BP

19

B

N/AP/HP

18

INV

17

S1

16

AGND

15

V

14

V

13

50/100/HOLD

12

CLK

11

PIN NAME FUNCTION

11 CLK

A-

D-

B

Clock input for biquad B.

2BP

A

Bandpass output for biquad A.

3 N/AP/HPANotch/allpass/highpass output for

biquad A.

4 INV

A

Inverting input of the summing op amp for biquad A.

5S1

A

Auxiliary signal input pin used in modes 1a, 1d, 4, 5, and 6b.

6S

A/B

7V

8V

A+

D+

Controls S2 input function.

Positive analog supply.

Positive digital supply.

9 LSh Reference point for clock input levels.

Logic threshold typically 1.4V above LSh voltage.

10 CLK

A

Clock input for biquad A.

12 50/100/HOLDInput pin to control the clock-to-

center-frequency ratio of 50:1 or 100:1, or to stop the clock to hold the last sample of the bandpass or lowpass outputs.

13 V

14 V

D-

A-

Negative digital supply.

Negative analog supply.

15 AGND Analog ground.

16 S 1

B

Auxiliary signal input pin used in modes 1a, 1d, 4, 5, and 6b.

17 INV

B

Inverting input of the summing op amp for biquad B.

18 N/AP/HPBNotch/allpass/highpass output for

biquad B.

19 BP

20 L P

B

Bandpass output for biquad B.

Lowpass output for biquad B.

2

ABSOLUTE MAXIMUM RATINGS

ML2111

Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied.

Lead Temperature (Soldering, 10 sec) ..................... 300ºC

Thermal Resistance (qJA)

20-Pin PDIP ...................................................... 67ºC/W

20-Pin SOIC ..................................................... 95ºC/W

Supply Voltage

|VA+|, |VD+| - |VA-|, |VD-| ...................................... 13V

OPERATING CONDITIONS

VA+, VD+ to LSh ..................................................... 13V

Inputs ......................|VA+, VD+| +0.3V to |VA-, VD-| -0.3V

Outputs ...................|VA+, VD+| +0.3V to |VA-, VD-| -0.3V

|VA+| to |VD+| ........................................................ ±0.3V

Junction Temperature .............................................. 150ºC

Temperature Range

ML2111CCX .............................................. 0ºC to 70ºC

ML2111CIP ............................................. -40ºC to 85ºC

Supply Range ........................................ ±2.25V to ±6.0V

Storage Temperature Range ...................... –65ºC to 150ºC

ELECTRICAL CHARACTERISTICS

Unless otherwise specified, VA+ = VD+ = 5V ± 10%, VA- = VD- = -5V ± 10%, CL = 25pF, V Clock Duty Cycle = 50%, TA = Operating Temperature Range (Note 1)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

FILTER

f

0(MAX)

Maximum Center Frequency (Note 2) Figure 15 (Mode 1), 100 kHz V

IN=1VPK

(0.707V

)Q £ 50, Q Accuracy £ ± 25%

RMS

Figure 15 (Mode 1), 150 kHz Q £ 20, Q Accuracy £ ± 15%

= 1.41VPK (1.000V

IN

RMS

),

f

0(MIN)

f

CLK

V

OS2,3

Minimum Center Frequency (Note 2) Figure 15 (Mode 1), 25 Hz V

IN=1VPK

f0 Temperature Coefficient f

Clock to Center Frequency Ratio 50:1, f

Q = 10, Figure 15 (Mode 1) C Suffix 49.45 49.85 50.25

Clock Frequency Q £ 20, Q Accuracy £ ±15% 2.5 7500 kHz

Clock Feedthrough f

Q Accuracy f

Q Temperature Coefficient f

DC Offset 50:1, f

(0.707V

)Q £ 50, Q Accuracy £ ± 30%

RMS

Figure 15 (Mode 1), 25 Hz Q £ 20, Q Accuracy £ ± 15%

< 5MHz -10 ppm/ºC

CLK

= 5MHz B Suffix 49.65 49.85 50.05

CLK

100:1, f

CLK

50:1, Figure 15 (Mode 1) C Suffix ±5 %

f

CLK

100:1, Figure 15 (Mode 1) C Suffix ±8 %

CLK

S

A/B

100:1, f

S

A/B

= 5MHz B Suffix 99.6 100.0 100.4

CLK

£ 5MHz 10 20 mV

= 5MHz, Q = 10, B Suffix ±3 %

= 5MHz, Q = 10, B Suffix ±4 %

< 5MHz, Q = 10 20 ppm/ºC

= 5MHz B Suffix 7 40 mV

CLK

= High or Low C Suffix 7 60 mV

= 5MHz B Suffix 14 60 mV

CLK

=High or Low C Suffix 14 100 mV

C Suffix 99.2 100.0 100.8

(P-P)

3

ML2111

ELECTRICAL CHARACTERISTICS (Continued)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

FILTER (Continued)

Gain Accuracy, DC Lowpass R1,R3 = 20kW, R2 = 2kW, 0.01 2 %

100:1, f0 = 50kHz, Q = 10

Gain Accuracy, Bandpass at f

0

R1,R3 = 20kW, R2 = 2kW, B Suffix 1 4 %

100:1, f0 = 50kHz, Q = 10 C Suffix 1 6 %

Gain Accuracy, DC Notch Output R1,R3 = 20kW, R2 = 2kW, 0.02 2 %

100:1, f0 = 50kHz, Q = 10

Noise (Note 3) Bandpass 100kHz, 50:1 103 µV

Figure 15 (Mode 1), 50kHz, 100:1 121 µV Q = 1, R1 = R2 = R3 = 2kW Lowpass 100kHz, 50:1 120 µV

Notch 100kHz, 50:1 115 µV

Noise (Note 3) Bandpass, 100kHz, 50:1 262 µV Figure 15 (Mode 1), R1 = 20kW 50kHz, 100:1 333 µV Q = 10, R3 = 20kW, R2 = 2kW Lowpass, 100kHz, 50:1 268 µV

R1 = 2kW 50kHz, 100:1 342 µV

Notch, 100kHz, 50:1 64 µV R1 = 2kW 50kHz, 100:1 72 µV

Crosstalk f

= 5MHz, f0= 100kHz -50 dB

CLK

FILTER, VA+ = VD+ = 2.25V, VA- = VD- = -2.25V, VIN = 0.707 x VPK (0.5 x V

f

0(MAX)

Maximum Center Frequency Figure 15 (Mode 1), 75 kHz

Q £ 50, Q Accuracy £ ± 30%

50kHz, 100:1 150 µV

50kHz, 100:1 135 µV

)

RMS

f

0(MIN)

f

CLK

Figure 15 (Mode 1), 100 kHz Q £ 20, Q Accuracy £ ± 15%

Minimum Center Frequency Figure 15 (Mode 1), 25 Hz

Q £ 50, Q Accuracy £ ± 30%

Figure 15 (Mode 1), 25 Hz Q £ 20, Q Accuracy £ ± 15%

Clock to Center Frequency Ratio 50:1, f

= 2.5MHz B Suffix 49.65 49.85 50.05

CLK

Q = 10, Figure 15 (Mode 1) C Suffix 49.45 49.85 50.25

100:1, f

= 2.5MHz B Suffix 99.60 100.0 100.4

CLK

C Suffix 99.20 100.0 100.8

Clock Frequency Q £ 20, Q Accuracy £ ±15% 2.5 5000 kHz

Q Accuracy f

= 2.5MHz, Q = 10, B Suffix ±4 %

CLK

50:1, Figure 15 (Mode 1) C Suffix ±8 %

f

= 2.5MHz, Q = 10, B Suffix ±3 %

CLK

100:1, Figure 15 (Mode 1) C Suffix ±6 %

4

ML2111

ELECTRICAL CHARACTERISTICS (Continued)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

FILTER, VA+ = VD+ = 2.25V, VA- = VD- = -2.25V, VIN = 0.707 x VPK (0.5 x V

Noise (Note 3) Bandpass 100kHz, 50:1 105 µV

Figure 15 (Mode 1), 50kHz, 100:1 123 µV Q = 1, R1 = R2 = R3 = 2kW Lowpass 100kHz, 50:1 122 µV

Notch 100kHz, 50:1 117 µV

Noise (Note 3) Bandpass, 100kHz, 50:1 265 µV Figure 15 (Mode 1), Q = 10, R1 = 20kW 50kHz, 100:1 335 µV R3 = 20kW, R2 = 2kW Lowpass, 100kHz, 50:1 270 µV

R1 = 2kW 50kHz, 100:1 245 µV

Notch, 100kHz, 50:1 65 µV R1 = 2kW 50kHz, 100:1 73 µV

OPERATIONAL AMPLIFIERS

V

OS1

A

VOL

DC Offset Voltage 215mV

DC Open Loop Gain RL = 1kW 95 dB

Gain Bandwidth Product 2.4 MHz

) (Continued)

RMS

50kHz, 100:1 152 µV

50kHz, 100:1 138 µV

RMS

Slew Rate 2.0 V/µs

Output Voltage Swing (Clipping Level) RL = 2kW, |V| from VA+ or V

A-

Output Short Circuit Current Source 50 mA

Sink 25 mA

CLOCK

V

Input Low Voltage 0.6 V

CLK

V

Input High Voltage 3.0 V

CLK

CLKA, CLKB Pulse Width |VD+| - |VD-| ³ 4.5V 100 ns

CLKA, CLKB Pulse Width |VD+| - |VD-| ³ .90V 66 ns

SUPPLY

(IA+)+(ID+) Supply Current, (VA+) + (VD+)f

(IA-)+(ID-) Supply Current, (VA-) + (VD-)f

I

LSh

Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions. Note 2: The center frequency is defined as the peak of the bandpass output. Note 3: The noise is meassured with an HP8903A audio analyzer with a bandwidth of 700kHz, which is 7.5 times the f

Supply Current, LSh f

= 5MHz 13 22 mA

CLK

= 5MHz 12 21 mA

CLK

= 5MHz 0.5 1 mA

CLK

0.5 1.2 V

at 50:1 and 15 times the f0 at 100:1.

0

5

ML2111

TYPICAL PERFORMANCE CURVES

0.4

0.0

RMS

f

CLK

Q = 20

(MHz)

Q = 50

Q = 10

–0.4

–0.8

–1.2

Deviation (%)

0

/f

–1.6

CLK

f

–2.0

–2.4

–2.8

04810

0.4

0.0

–0.4

–0.8

–1.2

Mode 1

T

= 25ºC

A

V

= 0.707V

IN

26

Q = 50

Q = 10

Q = 5

Figure 1A. f

Q = 20

CLK/f0

vs. f

Deviation (%)

0

/f

CLK

f

–1

–2

–3

(50:1, VS = ±5V)

CLK

0.5

0.0

–0.5

5

4

3

2

1

0

04810

Mode 1

Q = 10

V

= 0.707V

IN

26

RMS

f

CLK

TA = 85ºC

TA = 25ºC

(MHz)

TA = 25ºC

–1.6

Deviation (%)

0

/f

–2.0

CLK

f

–2.4

–2.8

–3.2

04810

16

14

12

10

8

Deviation (%)

6

0

/f

4

CLK

f

2

0

–2

0

0579

Mode 1

T

= 25ºC

A

V

= 0.707V

IN

26

V

16

RMS

f

(MHz)

CLK

Mode 1

T

= 25ºC

A

= 0.5V

IN

RMS

Q = 50

3

24

f

(MHz)

CLK

Q = 5

Figure 1B. f

Q = 10

Q = 20

Q = 5

8

CLK/f0

vs. f

Deviation (%)

0

–1.0

/f

CLK

f

–1.5

–2.0

(100:1, VS = ±5V)

CLK

10

8

6

4

Deviation (%)

0

/f

2

CLK

f

0

–2

Mode 1

Q = 10

V

= 0.707V

IN

04810

0619

26

Mode 1

Q = 10

V

= 0.5V

IN

RMS

f

CLK

f

CLK

TA = 85ºC

(MHz)

TA = 85ºC

(MHz)

TA = 25ºC

73

8254

Figure 1C. f

CLK/f0

vs. f

(50:1, VS = ±2.5V)

CLK

6

TYPICAL PERFORMANCE CURVES (Continued)

ML2111

5

4

3

2

Deviation (%)

1

0

/f

CLK

f

0

–1

–2

048

0.08

0.06

0.04

0.02

Mode 1

T

= 25ºC

A

V

= 0.5V

IN

RMS

2

1

f

(MHz)

CLK

V

Q = 50

Q = 20

Q = 10

Q = 5

7

63

5

Figure 1D. f

Mode 1

Q = 10

f

= 100kHz

0

f

= 5MHz

CLK

= 0.707V

IN

RMS

9

CLK/f0

vs. f

12

10

8

6

Deviation (%)

4

0

/f

CLK

f

2

0

–2

(100:1, VS = ±2.5V)

CLK

0.04

0.03

0.02

Mode 1

Q = 10

V

= 0.5V

IN

RMS

TA = 85ºC

TA = 25ºC

7

63

048

2

1

Mode 1

Q = 10

f

= 50kHz

0

f

= 5MHz

CLK

V

= 0.707V

IN

5

f

(MHz)

CLK

RMS

9

Deviation (%)

0.00

0

/f

CLK

f

–0.02

–0.04

–0.06

–40 20 60 100–20

Figure 2A. f

0.10

0.08

0.06

0.04

0.02

Deviation (%)

0

/f

0.00

CLK

f

–0.02

–0.04

40 800

Temperature (ºC)

Deviation vs. Temperature

CLK/f0

(50:1, VS = ±5V)

Mode 1

Q = 10

f

= 50kHz

0

f

= 2.5MHz

CLK

V

= 0.5V

IN

RMS

Deviation (%)

0

0.01

/f

CLK

f

0

–0.01

–40 20 60 100–20

Figure 2B. f

0.06

0.04

0.02

0.00

Deviation (%)

0

/f

–0.02

CLK

f

–0.04

CLK

V

Temperature (ºC)

Deviation vs. Temperature

CLK/f0

(100:1, VS = ±5V)

Mode 1 Q = 10

f

= 25kHz

o

= 2.5MHz = 0.5V

IN

RMS

40 800

–0.06

–40 40 800

Figure 2C. f

20 60 100–20

Temperature (ºC)

Deviation vs. Temperature

CLK/f0

(50:1, VS = ±2.5V)

–0.06

–40 40 800

Figure 2D. f

20 60 100–20

Temperature (ºC)

Deviation vs. Temperature

CLK/f0

(100:1, VS = ±2.5V)

7

ML2111

TYPICAL PERFORMANCE CURVES (Continued)

20

16

12

8

4

Q Deviation (%)

0

–4

–8

04810

Mode 1

T

= 25ºC

A

V

= 0.707V

IN

26

RMS

f

CLK

Q = 10

Q = 20

Q = 50

(MHz)

Q = 5

Figure 2E. Q Error vs. f

20

Mode 1

T

V

= 0.707V

IN

= 25ºC

A

RMS

Q = 10

Q = 5

Q = 20

15

10

5

0

Q Deviation (%)

–5

20

16

12

8

Q Deviation (%)

4

0

–4

(50:1, VS = ±5V)

CLK

20

16

12

8

Q Deviation (%)

4

Mode 1 Q = 10

V

= 0.707V

IN

04810

26

Mode 1 Q = 10

V

= 0.707V

IN

RMS

f

CLK

TA = 25ºC

TA = 85ºC

(MHz)

TA = 85ºC

–10

–15

04810

26

f

CLK

Q = 50

(MHz)

Figure 2F. Q Error vs. f

10

5

0

–5

Q Deviation (%)

–10

–15

–20

Mode 1

T

= 25ºC

A

V

= 0.5V

IN

RMS

13 64

02 75

f

CLK

Q = 5

(MHz)

Q = 10

Q = 20

Q = 50

0

–4

(100:1, VS = ±5V)

CLK

8

4

0

Q Deviation (%)

–4

–8

TA = 25ºC

04810

02 75

26

f

(MHz)

CLK

Mode 1 Q = 10

V

= 0.5V

IN

RMS

TA = 85ºC

13 64

f

(MHz)

CLK

TA = 25ºC

Figure 2G. Q Error vs. f

(50:1, VS = ±2.5V)

CLK

8

TYPICAL PERFORMANCE CURVES (Continued)

ML2111

16

12

Mode 1

T

8

4

0

Q Deviation (%)

–4

–8

–12

02 75

= 25ºC

A

V

= 0.5V

IN

RMS

Q = 50

13 64

f

(MHz)

CLK

Figure 2H. Q Error vs. f

0.4

0.2

0.0

Q = 10

Q = 5

Q = 20

16

12

8

4

0

Q Deviation (%)

–4

–8

–12

02 75

(100:1, VS = ±2.5V)

CLK

0.6

0.4

0.2

0.0

Mode 1 Q = 10

V

= 0.5V

IN

RMS

13 64

f

(MHz)

CLK

TA = 85ºC

TA = 25ºC

–0.2

Q Deviation (%)

–0.4

–0.6

–0.8

–40 40 800

20 60–20

Temperature (ºC)

f

= 100kHz

0

f

CLK

V

= 0.707V

IN

Mode 1

Q = 10

= 5MHz

RMS

Figure 3A. Q Deviation vs. Temperature

(50:1, VS = ±5V)

0.2

0.0

Q Deviation (%)

–0.2

Mode 1 Q = 10

f

= 50kHz

0

f

= 2.5MHz

CLK

V

= 0.5V

IN

RMS

100

–0.2

–0.4

Q Deviation (%)

–0.6

–0.8

–1.0

–40 40 800

20 60 100–20

Temperature (ºC)

f

0

f

CLK

V

= 0.707V

IN

Mode 1

Q = 10

= 50kHz

= 5MHz

RMS

Figure 3B. Q Deviation vs. Temperature

(100:1, VS = ±5V)

0.2

0.0

Q Deviation (%)

–0.2

Mode 1

Q = 10

f

= 25kHz

0

f

= 2.5MHz

CLK

V

= 0.5V

IN

RMS

–0.4

–40 40 800

20 60 100–20

Temperature (ºC)

Figure 3C. Q Deviation vs. Temperature

(50:1, VS = ±2.5V)

–0.4

–40 40 800

20 60 100–20

Temperature (ºC)

Figure 3D. Q Deviation vs. Temperature

(100:1, VS = ±2.5V)

9

ML2111

TYPICAL PERFORMANCE CURVES (Continued)

4

Mode 1

T

= 25ºC

A

f

= 5MHz

CLK

V

= 1V

IN

RMS

0

100:1

Deviation (%)

0

/f

–4

CLK

f

–8

0.1 1 10 100

50:1

Ideal Q (R3/R2)

Figure 4A. f

Deviation vs. Q (VS = ±5V) Figure 4A. f

CLK/f0

4

0

–4

0.05

Mode 1

T

= 25ºC

A

50:1 or 100:1

f

= 5MHz

CLK

V

= 1V

IN

RMS

0.0

Deviation (%)

0

/f

CLK

f

–0.05

0.1 1 10 100

Ideal Q (R3/R2)

CLK/fNOTCH

Deviation vs. Q (VS = ±5V)

2

0

–2

–8

Q Deviation (%)

Mode 1

T

–12

–16

= 25ºC

A

f

= 100kHz

0

f

= 5MHz

CLK

V

= ±5V

S

0.1 1 10 100

Ideal Q (R3/R2)

Figure 5A. Q Deviation vs. Q (50:1, VS = ±5V)

70

V

= 2V

V

OUT

= 1.41V

60

50

V

= 3V

OUT

40

30

20

10

Single Frequency Distortion Level (dB)

0

04080

Mode 1

Q = 1

f

= 100kHz

0

f

= 5MHz

CLK

V

= ±5V

S

T

= 25ºC

A

R

= 2kΩ

L

Low Pass Output

20

fIN (kHz)

V

= 0.5V

OUT

V

= 4V

OUT

10060

–4

Q Deviation (%)

Mode 1

T

= 25ºC

A

–6

f

= 50kHz

0

f

= 5MHz

CLK

V

= ±5V

S

–8

0.1 1 10 100

Ideal Q (R3/R2)

Figure 5B. Q Deviation vs. Q (100:1, VS = ±5V)

70

V

60

50

40

30

20

10

Single Frequency Distortion Level (dB)

0

02040

= 3V

OUT

V

= 4V

OUT

Mode 1

Q = 1

f

= 50kHz

0

f

= 5MHz

CLK

V

= ±5V

S

T

= 25ºC

A

R

= 2kΩ

L

Low Pass Output

10

V

= 2V

OUT

fIN (kHz)

V

OUT

= 1.41V

V

OUT

= 0.5V

5030

Figure 6A. Distortion vs. fIN (50:1, VS = ±5V) Figure 6B. Distortion vs. fIN (100:1, VS = ±5V)

10

TYPICAL PERFORMANCE CURVES (Continued)

ML2111

250

Mode 1

50:1

200

150

100

Noise (nV/√Hz)

50

0

0 200 300 500400100

Frequency (kHz)

R1 = R2 = R3 = 2kΩ

BANDPASS OUTPUT

V

= ±5V

S

f

= 100kHz

0

f

= 5MHz

CLK

Figure 7A. Noise Spectrum Density (Q = 1)

0.8

0.4

0.0

–0.4

Deviation (%)

Notch

/f

CLK

f

–0.8

–1.2

–1.6

Mode 1

T

= 25ºC

A

Q = 10

V

S

V

= 0.707V

IN

04810

100:1

50:1

= ±5V

RMS

26

f

(MHz)

CLK

2500

Mode 1

50:1

2000

1500

1000

Noise (nV/√Hz)

500

0

0 200 300 500400100

Frequency (kHz)

R1 = R3 = 20kΩ,

R2 = 2kΩ

BANDPASS OUTPUT

V

= ±5V

S

f

= 100kHz

0

f

= 5MHz

CLK

Figure 7B. Noise Spectrum Density (Q = 10)

100

80

60

40

Notch Depth (dB)

20

Mode 1

T

= 25ºC

A

Q = 10

V

= ±5V

S

V

= 0.707V

IN

0

04810

100:1

50:1

RMS

26

f

(MHz)

CLK

Figure 8. f

16

Q = 10

T

= 25ºC

A

L

= V

Sh

50:1

14

12

Supply Current (mA)

10

8

234 65

SS

f

CLK

= 3MHz

CLK/fNOTCH

f

= 5MHz

CLK

Supply Voltage (±V)

vs. f

f

CLK

f

CLK

= 10MHz

= 250kHz

Figure 10. Supply Current vs. Supply Voltage

Figure 9. Notch Depth vs. f

15

Mode 1

V

= ±5V

S

14

f

= 5MHz

CLK

50:1

13

12

Supply Current (mA)

11

10

–40 20 60 100–20

Temperature (ºC)

40 800

CLK

Figure 11. Supply Current vs. Temperature

11

ML2111

FUNCTIONAL DESCRIPTION

POWER SUPPLIES

f

CLK/f0

RATIO

The analog (VA+) and digital (VD+) supply pins, in most cases, are tied together and bypassed to AGND with 100nF and 10nF disk ceramic capacitors. The supply pins can be bypassed separately if a high level of digital noise exists. These pins are internally connected by the IC substrate and should be biased from the same DC source. The ML2111 operates from either a single supply from 4V to 12V, or with dual supplies at ±2V to ±6V.

CLOCK INPUT PINS AND LEVEL SHIFT

With dual supplies equal to or higher than ±4.0V, the LSh pin can be connected to the same potential as either the AGND or the VA- pin. With single supply operation the negative supply pins and LSh pin should be tied to the system ground. The AGND pin should be biased half way between VA+ and VA-. Under these conditions the clock levels are TTL or CMOS compatible. Both input clock pins share the same level shift pin.

50/100/HOLD

Tying the 50/100/HOLD pin to the VA+ and VD+ pins makes the filter operate in the 50:1 mode. Tying the pin half way between VA+ and VA- makes the filter operate in the 100:1 mode. The input range for 50/100/HOLD is either 2.5V ±0.5V with a total power supply range of 5V, or 5V ±0.5V with a total power supply range of 10V. When 50/100/HOLD is tied to the negative power supply input, the filter operation is stopped and the bandpass and lowpass outputs act as a sample/hold circuit which holds the last sample.

S1A & S1

These voltage signal input pins should be driven by a source impedance of less than 5kW. The S1A and S1B pins can be used to feedforward the input signal for allpass filter configurations (see modes 4 & 5) or to alter the clock-to-center-frequency ratio (f modes 1b, 1c, 2a, & 2b). When these pins are not used they should be tied to the AGND pin.

S

A/B

When S summing device is tied to the lowpass output. When the S

A/B

switches to ground.

AGND

B

) of the filter (see

CLK/f0

is high, the S2 negative input of the voltage

A/B

pin is connected to the negative supply, the S2 input

The ML2111 is a sampled data filter and approximates continuous time filters. The filter deviates from its ideal continuous filter model when the (f and when the Qs are low.

f0 ´ Q PRODUCT RATIO

The f0 ´ Q product of the ML2111 depends on the clock frequency and the mode of operation. The f0 ´ Q product is mainly limited by the desired f0 and Q accuracy for clock frequencies below 1MHz in mode 1 and its derivatives. If the clock to center frequency ratio is lowered below 50:1, the f0 ´ Q product can be further increased for the same clock frequency and for the same Q value.

Mode 3, (Figure 23) and the modes of operation where R4 is finite, are "slower" than the basic mode 1. The resistor R4 places the input op amp inside the resonant loop. The finite GBW of this op amp creates an additional phase shift and enhances the Q value at high clock frequencies.

OUTPUT NOISE

The wideband RMS noise on the outputs of the ML2111 is nearly independent of the clock frequency, provided that the clock itself does not become part of the noise. Noise at the BP and LP outputs increases for high values of Q.

) ratio decreases

CLK/f0

FILTER FUNCTION DEFINITIONS

Each filter of the ML2111, along with external resistors and a clock, approximates second order filter functions. These are tabulated below in the frequency domain.

1. Bandpass function: available at the bandpass output

pins (BPA, BPB), Figure 12.

s



w

0

Gs H

()=

OBP

where:

H

= Gain at w = w

OBP

f0 = w0/2p. The center frequency of the complex pole pair is f0. It is measured as the peak frequency of the bandpass output.

20

s

Q

s



w



+

 

 

Q



0

2

+

w

0

(1)

AGND is connected to the system ground for dual supply operation. When operating with a single positive supply the analog ground pin should be biased half way between VA+ and VA-, and bypassed with a 100nF capacitor. The positive inputs of the internal op amps and the reference point of the internal switches are connected to the AGND pin.

12

Q = the Quality factor of the complex pole pair. It is the ratio of f0 to the -3dB bandwidth of the 2nd order bandpass function. The Q is always measured at the filter BP output.

FILTER FUNCTION DEFINITIONS (Continued)

ML2111

2. Lowpass function: available at the LP output pins,

Figure 13.

2

w

Gs H

()=

OLP

where:

H

= DC gain of the LP output

OLP

3. Highpass function: available only in mode 3 at

N/AP/HPA and N/AP/HPB, Figure 14.

Gs H

()=

OHP

H

= Gain of the HP output for f ® f

OHP

20

s

+

20

s

0

s



w

 





+

 

 

Q



2

s

w

s



 



Q

2

+

w

0

2

w

+

0

CLK

/2.

(2)

(3)

H

0.707 H

GAIN (V/V)

OBP

Q

ff

=-+

L

ff

= +

H

BANDPASS OUTPUT

f

0

H

=

LH

2













2













2

f (LOG SCALE)

f

0

=

ff

-

HL



121



0

QQ







121



0

QQ

 

L

fff

;

0

+

1

+

 





 

 

H

0.707 H

GAIN (V/V)

ff

LOWPASS OUTPUT

OP

OLP

= -

C



0





ff

HH

=

OP OLP

f

P

f (LOG SCALE)



1

QQ

2

= -

P

0



+-





22





1

2

1

-

Q

f

C

1

2

1

2

Q

1

2

Q

4

2



+

1





H

OHP

0.707 H

OHP

GAIN (V/V)

ff

C

Figure 12.

HIGHPASS OUTPUT

OP





= -

0

1





!

HH

OP OHP

2

ff

= -

P

0

=

f

C

P

f (LOG SCALE)



1

QQ



+-

1





22







!

1

Q

2

1

-

Q

1



1





2

1

-

" #

2

#

$

1

2

Q

4

-

1

"

2

#

+

1

# #

$

Figure 13.

Figure 14.

13

ML2111

FILTER FUNCTION DEFINITIONS

4. Notch function: available at N/AP/HPA and N/AP/HP

for several modes of operation.

2

s

Gs H

()=

ON

2

H

= Gain of the notch output for f ® f

ON2

H

= Gain of the HP output for f ® 0

ON1

49

s



20

s

+





fn = wn/2p. The frequency of the notch occurrence is fn.

5. Allpass function: available at N/AP/HPA and N/AP/

HPB for modes 4 and 4a.

s

20

s

-

Gs H

()=

OAP

H

= Gain of the allpass output for 0 < f < f

OAP

s

2

s

+

For allpass functions, the center frequency and the Q of the numerator complex zero pair is the same as the denominator. Under these conditions the magnitude response is a straight line. In mode 5, the center frequency fZ of the numerator complex zero pair is different than f0. For high numerator Q's, the magnitude response will have a notch at fZ.

2

+

w

n



w



+

w



Q





w

+

w

Q



w

Q

0

+

w

0

2

0

2

CLK

/2.

CLK

(4)

(5)

/2

OPERATION MODES

B

There are three basic modes of operation — Modes 1, 2, and 3 , each of which has derivatives; and four secondary modes of operation — Modes 4, 5, 6, and 7, each of which also has derivatives.

In Figure 15, the input amplifier is outside the resonant loop. Because of this, mode 1 and its derivatives (modes 1a, 1b, 1c, and 1d) are faster than modes 2 and 3.

Mode 1 provides a clock tunable notch. It is a practical configuration for second order clock tunable bandpass/ notch filters. In mode 1, a band pass output with a very high Q, together with unity gain can be obtained with the dynamics of the remaining notch and lowpass outputs.

Mode 1a (Figure 16) represents the simplest hookup of the ML2111. It is useful when voltage gain at the bandpass output is required. However, the bandpass voltage gain is equal to the value of Q, and second order, clock tunable, BP resonator can be achieved with only 2 resistors. The filter center frequency directly depends on the external clock frequency. Mode 1a is not practical for high order filters as it requires several clock frequencies to tune the overall filter response.

Modes 1b and 1c, Figures 17 and 18, are similar. They both produce a notch with a frequency which is always equal to the filter center frequency. The notch and the center frequency can be adjusted with an external resistor ratio.

½ ML2111 ½ ML2111

R3

R2

R1

V

IN

4 (17)

+

S

A/B

6

f

= = =- =-

15

V+

f

CLK

ffH

;; ; ;

100 50 1 1

nOLP OBP00

()

H

ON1

N

3 (18)

+

R2

=- =;

R

1

Q

Σ

S1

A

5 (16)

R2

R

R3 R2

BP

2 (19) 1 (20)

H

LP

R3 R

Figure 15. Mode 1: 2nd Order Filter Providing Notch,

Bandpass, Lowpass

V

R3

R2

4 (17)

+

S

A/B

6

V+

15

f

H non inverting H

CLK

===-

100 50

()

11=- =-();

OBP OLP2

IN

BP2

S1

A

5 (16)

3 (18)

+

Σ

R3

Q

;; ;

H

OBP01

R2

BP1

2 (19)

R3 R2

Figure 16. Mode 1a: 2nd Order Filter Providing

Bandpass, Lowpass

LP

1 (20)

14

ML2111

MODE BPA, BP

B

6a LP HP

6b LP LP

7LPAP

Table 1. First Order Functions.

MODE LPA, LP

B

BPA, BP

B

N/AP/HP

1 LP BP Notch

1a LP BP BP

1b LP BP Notch

N/AP/HPA, N/AP/HP

A&B

f

CLK

100 50()

f

CLK

100 50()

f

CLK

100 50

B

f

1

+

f

C

f

CLK

100 50()

f

CLK

100 50()

f

CLK

100 50()

0

R

RR

56()

+

R2



R3

R2



R3

R2



R3

6

f

CLK

100 50

f

Z

f

CLK

100 5 0()

f

N

f

0

1

+

R2



R3

R

6

RR

56()

+

1c LP BP Notch

1d LP BP

2 LP BP Notch

2a LP BP Notch

2b LP BP Notch

3LPBPHP

3a LP BP Notch

4LP BPAP

f

CLK

f



CLK

100 50

100 50()

f

CLK

100 50

100 50 4656()

100 50 4()

+

f

CLK

+ +

f

CLK

+

f

CLK



f

CLK



f

CLK

100 50()

R

6

RR

56()

+

R2

1

R

4()

R2

1

RRRR

4656()

+

R2

RRRR

+

R2

R

R2

R

f

CLK

100 50

f

CLK

100 50()

f

CLK

100 50

f

CLK

100 50

f

CLK h

100 50()

R



+



6

RR

56()

+

1

RR

R

6

RR

56()

+

R

l

R

56()

+

6

4a LP BP AP

5LP BPCZ

Table 2. Second Order Functions

f

CLK

100 50 4()

100 50



f

CLK

+

R2

R

1

R2 R

f

CLK

4()

100 50

R2

1

-

R

4()

15

ML2111

/

Σ

S1

A

5 (16)

R5

BP

2 (19)

LP

1 (20)

f

Q

Hf H f

H

CLK

=+

100 50

()

R3 R2

= 

16

ON ON

12

=- =

OBP OLP

RR

0

R3

H

;

R

1

56

6

RR

56

+

R

6

Rk=+

+

 



++1

16 5 6

ff

=

;

n00

<1

55; W

f

CLK

21

R2 R

-

RRR

/



=-

 

1

0

R2

R

5

R6

R3

R2

V

R1

IN

4 (17)

+

S

A/B

6

V+

15

N

3 (18)

+

Figure 17. Mode 1b: 2nd Order Filter Providing Notch, Bandpass, Lowpass

Σ

S1

A

5 (16)

R5

BP

2 (19)

LP

1 (20)

f

Q

Hf H f

CLK

=

100 50

()

R3

=

R2RRR

0

= 

16

ON ON

12

R

6

RR

56

+

6

;

+

56

 



ff

=

;

n00

f

CLK

21



=-

 

R2 R

;

R6

R3

R2

V

R1

IN

4 (17)

+

N

3 (18)

+

S

A/B

6

V-

15

H

OBP OLP

R3

=- =

H

R

1

R2 R

-

1

RRR

+

656

/

0

5

Rk

<

55;

;

W

Figure 18. Mode 1c: 2nd Order Filter Providing Notch, Bandpass, Lowpass

R3B

R2

V

R1

IN

4 (17)

+

S

A/B

6

V+

15

N

3 (18)

+

Σ

S1

A

5 (16)

R3A

BP

2 (19)

LP

1 (20)

f

H

CLK A

==+=-

100 50

=- - 

OLP N IN

Q

;; ;

()

R2

V

;

R

11

R3

H

OBP0

B

V

1

R2

R

R2

R

Q

1

Figure 19. Mode 1d: 2nd Order Filter Providing Bandpass and Lowpass for Qs Greater Than or Equal To 1.

16

R4

/

ML2111

R3

R2

V

R1

IN

6

R1

6

S

V+

A/B

4 (17)

+

15

Figure 20. Mode 2: 2nd Order Filter Providing Notch, Bandpass, Lowpass

R4

R3

R2

+

15

Figure 21. Mode 2a: 2nd Order Filter Providing Notch, Bandpass, Lowpass

3 (18)

R6

3 (18)

N

S1

A

5 (16)

+

Σ

R5

N

S1

A

5 (16)

+

Σ

BP

2 (19)

BP

2 (19)

LP

1 (20)

LP

1 (20)

f

CLK

=+=

f

0

100 50

()

R3

Q

=+ =

H

OBP ON

Hf

ON

=++

f

=+

n

Q

=++

Hf

ON1

H

OLP

1

R2

R3

-

=

R

f



CLK





2



21

f

CLK

100 50

()

f

CLK

100 50

()

R3

1

R2

0

=-

16

=

14656

R2 R R R R

+++

0

R2

1

;

4 100 50

R

R2

H

;

OLP

R

4

Hf

;

=

16

1

R2

-



=

 

R

R2

1

4656 1

RRRR

R

1

RR

+

56 2 1

R2 RRRR

4

56

%

R2

&

R

1

14656

+++

'

R2 R

-

//

5

f

CLK

f

n

-

+

14

0

14

+

6

Hf

;;

6

;

+

RRR

16 5 6

++

R2 R R R R

//

05

1

0

;

()

R2 R

1

/

R2 R

0

R2 R

-

+1

0

ON

;

/

5

1

R2 R

;;

2

/

;

/

5

R3

=-

H

OBP0





 

05

R

f

CLK

R2



=-

 

R

(

;

) *

5

R4

f

LP

Hf

H

Σ

R5

S1

A

5 (16)

BP

2 (19)

1 (20)

R6

R3

R2

V

R1

IN

4 (17)

+

S

A/B

6

V-

15

Figure 22. Mode 2b: 2nd Order Filter Providing Notch, Bandpass, Lowpass

N

3 (18)

+

CLK

=+

0

100 50 4656

f

CLK

=

n

=-

16

ON1







ON



=

OLP

R2 R R R R

05 0 5

R2

RRRR

R

6

RR

+

56 4

%

R2

0

f

CLK

21 1

//

&

R

R2 R R R R

1

05

'

R2



=- =-;;

 

R

R2 R

-

++

4656

;

+()

R3R2R2

Q

= +

;;

/

RRR

656

//

4656

H

OBP2

1

RRRR

+

05

++

R3

R

6

+100 50

56()

(

;

) *

17

ML2111

OPERATION MODES (Continued)

The clock to center frequency ratio range is:

f

500



1

100150

or

100150

CLK

f

0

f

CLK



1

f

0

or

(mode 1c) (6)

1

100250

or

(mode 1b) (7)

2

The input impedance of the S1 pin is clock dependent, and in general R5 should not be larger than 5kW for f

2.5MHz and 2kW for f

> 2.5MHz. Mode 1c can be

CLK

used to increase the clock-to-center-frequency ratio beyond 100:1. The limit for the (f

) ratio is 500:1 for

CLK/f0

this mode. The filter will exhibit large output offsets with larger ratios. Mode 1d (Figure 19) is the fastest mode of operation: center frequencies beyond 20kHz can easily be achieved at a 50:1 ratio.

R4

R3

R2

V

R1

IN

4 (17)

+

HP

3 (18)

+

Σ

S1

A

5 (16)

BP

2 (19)

<

Modes 2, 2a, and 2b (Figures 20, 21, and 22) have notch outputs whose frequency, fn, can be tuned independently from the center frequency, f0. However, for all cases fn < f0. These modes are useful when cascading second order functions to create an overall elliptic highpass, bandpass or notch response. The input amplifier and its feedback resistors R2 and R4 are now part of the resonant loop. Because of this, mode 2 and its derivatives are slower than mode 1 and its derivatives.

In Mode 3 (Figure 23) a single resistor ratio, R2/R4, can tune the center frequency below or above the f f

/50) ratio. Mode 3 is a state variable configuration

CLK

since it provides a highpass, bandpass, lowpass output through progressive integration. Notches are acquired by summing the highpass and lowpass outputs (mode 3a, Figure 24). The notch frequency can be tuned below or

LP

1 (20)

f

H

CLK

==

0

100 50 4 4

()

=- =- =-

OHP OLP OBP

R2 R

R2

H

;;

R

1

R3R2R2

Q

;;

R

4

H

R

11

R

CLK

R3

R

/100 (or

S

A/B

6

V-

15

Figure 23. Mode 3: 2nd Order Filter Providing Highpass, Bandpass, Lowpass — ½ ML2111

R2RR3

Q

=

R4

R3

R2

V

R1

IN

4 (17)

+

S

A/B

6

V-

15

HP

3 (18)

+

Σ

S1

A

5 (16)

BP

2 (19)

R

h

LP

1 (20)

R

l

+

H

Hff Q

ON

R

g

External Op Amp

f

CLK

==

f

0

100 50 4 100 50

()

R2

=- =- =-

OHP OBP OLP

==  - 

16

0

NOTCH

R2 R

H

;;;

R

11

R



g



R



l



Hf



2

ON



Hf

ON

f

;

H



CLK h

f

n

()

R3

H

R

OLP

1

g

R

h

f



CLK

=;

 

21

0

= 

16

4

R

H

OHP

R

g

RR2R

h

R

g

R

l

R2

R

;

R

l

4

R

1



;

 

4

R

1

R

Figure 24. Mode 3a: 2nd Order Filter Providing Highpass, Bandpass, Lowpass, Notch — ½ ML2111

18

OPERATION MODES (Continued)

ML2111

above the center frequency through the resistor ratio Rh/ Rl. Because of this, modes 3 and 3a are the most versatile and useful modes for cascading second order sections to obtain high order elliptic filters. For very selective bandpass/bandreject filters the mode 3a approach , as in Figure 24, yields better dynamic range since the external op amp helps to optimize the dynamics of the output nodes of the ML2111.

Modes 4 and 5 are useful for constructing allpass response filters. Mode 4, Figure 25, gives an allpass response, but due to the sampled nature of the filter, a slight 0.5 dB peaking can occur around the center

R3

R2

R1 = R2

V

IN

4 (17)

+

S

A/B

6

15

frequency. Mode 4a (Figure 26) gives a non-inverting output, but requires an external op amp. Mode 5 is recommended if this response is unacceptable. Mode 5 (Figure 27) gives a flatter response than mode 4 if R1 = R2 = 0.02 ´ R4.

Modes 6 and 7 are used to construct 1st order filters. Mode 6a (Figure 28) gives a lowpass and a highpass single pole response. Mode 6b (Figure 29) gives an inverting and non-inverting lowpass single pole filter response. Mode 7 (Figure 30) gives an allpass and lowpass single pole response.

AP

3 (18)

+

Σ

S1

A

5 (16)

BP

2 (19) 1 (20)

LP

V+

f

o

=

100 50

f

CLK

05

R

3

Q

=

;

H

;

OAP

R

2

R

2

=

-

;

H

OLP

R

1

=-

2

H

;

OBP

R

3



=



-

2









R

2

Figure 25. Mode 4: 2nd Order Filter Providing Allpass, Bandpass, Lowpass — ½ ML2111

R4

R3

f

CLK

==

f

R2

V

IN

R1

4 (17)

+

S

A/B

6

15

HP

3 (18)

+

Σ

S1

A

5 (16)

BP

2 (19)

LP

1 (20)

R

R5

External Op Amp

0

100 50 4 4

()

R

H

OAP OHP

H

OLP

H

OBP

5

==-

R

21

R

=-

R2 R

H

;;

4

;

R

1

R3R2R2

;;

Q

R

R2

R

R3 R

1

V-

2R

+

Figure 26. Mode 4a: 2nd Order Filter Providing Highpass, Bandpass, Lowpass, Allpass — ½ ML2111

19

ML2111

R4

R3

R2

V

R1

IN

H

4 (17)

+

S

A/B

6

=+=-

f

0

OBP OZ

15

V+

f

CLK

100 50

()

R3

Q

=+ =-1

R2

R3 R2



1

 

=+

CZ

S1

A

5 (16)

3 (18)

+

Σ

R2

1

;

410050

R

R2

Q

;;

R

41

R2



Hf

;

 

R

1

f

CLK

Z

()

R3

Z

R

=

0

16

1

RR

05

RR2

0

BP

LP

2 (19)

1 (20)

1

R

1

;

4

R

1

R

4

-

411

/

41

/

;

+

5

R3

V

IN

R2

R1

4 (17)

+

S

A/B

6

f

C

15

V-

f

CLK

=  =- =-

100 50 1 1()

HP

S1

A

5 (16)

3 (18)

+

Σ

R2

H

;;

OLP OHP

R3

R

2 (19) 1 (20)

H

LP

Figure 28. Mode 6a: 1st Order Filter Providing

Highpass, Lowpass — ½ ML2111

R2 R



Hf

OZ



 

f

CLK

R2

 



H

==

;

OLP

R

11

14

/

05

R2 R

+21

/

0

5

R2 R

+

Figure 27. Mode 5: 2nd Order Filter Providing

Numerator Complex Zeroes, Bandpass, Lowpass — ½

ML2111

V

LP1

3 (18)

+

Σ

IN

5 (16)

S1

A

LP2

2 (19)

1 (20)

R3

R2

4 (17)

+

S

A/B

6

15

R3

R2 = R1

R1 = R2

V

IN

4 (17)

+

S

A/B

6

15

AP

3 (18)

+

Σ

S1

A

5 (16)

LP

2 (19)

1 (20)

V-

f

CLK

= ==-

C

100 50

()

R2

HH

;;

R3

1

OLP OLP

12

R3 R2

Figure 29. Mode 6b: 1st Order Filter Providing Lowpass

— ½ ML2111

20

V-

f

ff

==  =-

PZ

CLK

100 502()

|GAIN AT OUTPUT| = 1 FOR

R2 R3

H

;

OLP

02f

R2 R3

f

CLK

Figure 30. Mode 7: 1st Order Filter Providing Allpass,

Lowpass — ½ ML2111

ML2111

HP

INV

CLK

BP

V

20

LP

B

S1

B

R32

19

R22

18

17

16

15

Q1 = 0.541

14

-

V

A

13

-

D

12

Q2 = 1.302

-5V

5V

11

B

V

OUT

0

–10

–20

–30

(dB)

IN

–40

/V

OUT

–50

V

–60

–70

–80

10k 100k 1M

FREQUENCY (Hz)

V

IN

1V

5V

Clock 5MHz

R31

R21

p-p

1

LP

A

2

BP

A

3

HP

A

4

INV

A

5

S1

A

6

S

AGND

A/B

7

VA+

8

+

V

D

9

LSh

CLK

50/100

A

10

1% RESISTOR VALUES

R21 = 3746Ω R31 = 2003Ω

R22 = 1996Ω R32 = 2604Ω

Figure 31. 4th Order, 100kHz Lowpass Butterworth Filter Obtained by Cascading Two Sections in Mode 1a.

101,777Hz

–3.058dB

V

OUT

0

–10

–20

149,871Hz

–30

(dB)

IN

–40

/V

OUT

–50

V

–60

–70

–80

10k 100k 1M

FREQUENCY (Hz)

–0.31dB

V

IN

2.82V (1V

RMS

p-p

)

R11

5V

Clock 7.5MHz

R31

R21

BP

HP

INV

V

CLK

20

LP

B

19

B

18

B

17

B

16

S1

B

15

14

-

V

A

13

-

D

12

R12

R32

R22

Q1 = Q2 = 10

-5V

5V

11

B

1

LP

A

2

BP

A

3

HP

A

4

INV

A

5

S1

A

6

S

AGND

A/B

7

VA+

8

+

V

D

9

LSh

CLK

50/100

A

10

RESISTOR VALUES

R11 = 20kΩ R21 = 2kΩ R31 = 20kΩ

R12 = 20kΩ R22 = 2kΩ R32 = 20kΩ

Figure 32. Cascasding 2 Sections Connected in Mode 1, each with Q = 10, to obtain a Bandpass Filter with Q = 15.5,

and f0 = 150kHz (f

= 7.5MHz).

CLK

21

ML2111

R12

LP

BP

HP

INV

S1

V

CLK

20

B

19

B

-

V

A

-

D

R22

18

17

16

15

14

13

12

-5V

5V

V

OUT

11

B

10

0

–10

166,224Hz

–20

(dB)

IN

–30

/V

OUT

–40

V

3–50

–60

–70

10k 100k 1M

–3.121dB

V 1V

1

LP

A

2

BP

R21

R11

IN

p-p

5V

A

3

HP

A

4

INV

A

5

S1

A

6

S

AGND

A/B

7

VA+

8

+

V

D

9

LSh

CLK

50/100

A

10

FREQUENCY (Hz)

Clock 7.51MHz

RESISTOR VALUES

R11 = R21 = R12 = R22 = 2.0kΩ

Figure 33. Cascading Two Sections in Mode 1d, Each with Q =1, (Independent of Resistor Ratios) to Create a Sharper 4th

Order Lowpass Filter.

V

2.82V

IN

p-p

R31

R22

R32

R34

5V

Clock 6.5MHz

1

R24

LP

2

BP

3

HP

4

INV

5

S1

6

S

A/B

7

VA+

8

V

D

9

LSh

10

CLK

LP

A

BP

A

HP

A

INV

A

S1

A

AGND

V

A

+

V

D

50/100

CLK

A

1% RESISTOR VALUES

R21 = R22 = R23 = R24 = 2kΩ R31 = 80kΩ

R32 = 4.9kΩ R34 = 100Ω

R23

V

20

B

19

B

18

B

17

B

16

B

15

14

13

12

R21

-5V

5V

11

B

OUT

(dB)

IN

/V

OUT

V

–5

–10

–15

–20

–25

–30

–35

–40

–45

–50

0

127

129,070Hz

130

133

FREQUENCY (kHz)

Figure 34. Notch Filter with Q = 50 and f0 = 130kHz. This Circuit Uses Side A in Mode 1d and the Side B Op Amp to

Create a Notch Whose Depth is Controlled by R31. The Notch is Created by Subtracting the Bandpass from VIN. The

Bandpass of Side A is Subtracted Using the Op Amp of Side B.

22

ML2111

OPERATION MODES (Continued)

Mode 1a is a good choice when Butterworth filters are desired since they have poles in a circle with the same f0. Figure 31 shows an example of a 4th order, 100kHz lowpass Butterworth filter clocked at 5MHz.

A monotonic passband response with a smooth transition band results, showing the circuit's low sensitivity, even though 1% resistors are used which results in an approximate value of Q.

Figure 32 gives an example of a 4th order bandpass filter implemented by cascading 2 sections, each with a Q of

10. This figure shows the amplitude response when f

7.5MHz, resulting in a center frequency of 150kHz and a Q of 15.5.

Figure 33 uses mode 1d of a 4th order flter where each section has a Q of 1, independent of resistor ratios. In this mode, the input amplifier is outside the damping (Q) loop. Therefore, its finite bandwidth does not degrade the response at high frequency. This allows the amplifier to be used as an anti-aliasing and continuous smoothing fliter by placing a capacitor across R2.

CLK

=

OFFSETS

Switched capacitor integrators generally exhibit higher input offsets than discrete RC integrators.

These offsets are mainly the charge injection of the CMOS switchers into the integrating capacitors. The internal op amp offsets also add to the overall offset budget.Figure 35 shows half of the ML2111 filter with its equivalent input offsets V

The DC offset at the filter bandpass output is always equal to V

. The DC offsets at the remaining two outputs

OS3

(Notch and LP) depend on the mode of operation and external resistor ratios. Table 3 illustrates this.

It is important to know the value of the DC output offsets, especially when the filter handles input signals with large dynamic range. As a rule of thumb, the output DC offsets increase when:

1. The Qs decrease

2. The ratio (f

) increases beyond 100:1. This is done

CLK/fo

by decreasing either the (R2/R4) or the R6/(R5 + R6) resistor ratios.

OS1

, V

OS2

, & V

OS3

.

(17)

(16)

(18)

5

3

V

OS1

4

+

V

OS2

+

Σ

(19)

2

+

15

Figure 35. Equivalent Input Offsets of ½ of an ML2111 Filter.

(20)

1

V

OS3

+

23

ML2111

MODE V

N/AP/HPA, N/AP/HP

1, 4 V

1a V

1b V

1c V

1d V

2, 5 [V

2a [V

2b [V

[(1/Q) + 1 + ||H

OS1

[1 + (1/Q)] – V

OS1

[(1/Q)] + 1 + R2/R1] – V

OS1

[(1/Q)] + 1 + R2/R1] – V

OS1

[1 + R2/R1] V

OS1

(1 + R2/R1 + R2/R3 + R2/R4) – V

OS1

[R4/(R2 + R4)] + V

(1 + R2/R1 + R2/R3 + R2/R4) – V

OS1



Rk

41

16

R2 R k

41 41

++

!

(1 + R2/R1 + R2/R3 + R2/R4) – V

OS1



Rk

4

!

16

+

R2 R k

"

+

#

16 16

#

$

"

+

#

44

16 16

#

$

||] – V

OLP

/Q V

OS3

[R2/(R2 + R4)] V

OS2



V

+

OS

V

OS

2

R2 R k

!



2

R2 R k

!

OSN

B

/Q V

OS3

/Q V

OS3

/Q V

OS3

(R2/R3)] ´

OS3

(R2/R3)] ´

OS3

R2

++

R2

+

"

k

=

;

# #

$

(R2/R3)] ´

OS3

"

=

;

k

# #

$

R

6

RR

56

+

R

6

+

RR

56

V

OSBP

BPA, BP

OS3

V

OS3

V

OS3

B

V

~(V

~V V

V

~V V

V

OSLP

LPA, LP

B

– V

OSN

OS2

– V

OS2

– V

OSN

16

OSN OS

– V

16

OSN OS

16

OSN OS

) (1 + R5/R6)

OS2

RR

+

-

OS2

-

-+

56

2

RR

+

526

– V

/Q

OS3

56

RR

+

2

526

RR

+

R

5





1





2





R

6

3, 4a V

OS2

Table 3.

RRRR2R

4

44 4 4

V

OS3



V

1

+++

OS OS OS123

1

!

" #

R3

$

V

-

R





-









R2

V

R













R3

24

PHYSICAL DIMENSIONS inches (millimeters)

Package: P20

20-Pin PDIP

1.010 - 1.035

(25.65 - 26.29)

20

ML2111

0.060 MIN (1.52 MIN) (4 PLACES)

0.170 MAX

(4.32 MAX)

0.125 MIN

(3.18 MIN)

20

PIN 1 ID

1

(12.65 - 13.00)

0.498 - 0.512

0.055 - 0.065 (1.40 - 1.65)

0.016 - 0.022

(0.40 - 0.56)

0.100 BSC (2.54 BSC)

SEATING PLANE

Package: S20

20-Pin SOIC

0.240 - 0.260 (6.09 - 6.61)

0.015 MIN (0.38 MIN)

0.295 - 0.325 (7.49 - 8.26)

0º - 15º

0.008 - 0.012 (0.20 - 0.31)

0.024 - 0.034 (0.61 - 0.86)

(4 PLACES)

0.090 - 0.094 (2.28 - 2.39)

0.291 - 0.301 (7.39 - 7.65)

PIN 1 ID

1

0.050 BSC

(1.27 BSC)

0.012 - 0.020 (0.30 - 0.51)

0.095 - 0.107 (2.41 - 2.72)

SEATING PLANE

0.398 - 0.412

(10.11 - 10.47)

0.005 - 0.013 (0.13 - 0.33)

0º - 8º

0.022 - 0.042 (0.56 - 1.07)

0.007 - 0.015 (0.18 - 0.38)

25

ML2111

ORDERING INFORMATION

PART NUMBER TEMPERATURE RANGE PACKAGE

ML2111CCP (EOL) 0°C to 70°C 20-Pin PDIP (P20)

ML2111CCS 0°C to 70°C 20-Pin SOIC (S20)

ML2111CIP (OBS) -40°C to 85°C 20-Pin PDIP (P20)

Micro Linear Corporation

2092 Concourse Drive

San Jose, CA 95131 Tel: (408) 433-5200 Fax: (408) 432-0295

Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376; 5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174; 5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165; 5,825,223; 5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending.

Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness of the contents of this publication and reserves the right to makes changes to specifications and product descriptions at any time without notice. No license, express or implied, by estoppel or otherwise, to any patents or other intellectual property rights is granted by this document. The circuits contained in this document are offered as possible applications only. Particular uses or applications may invalidate some of the specifications and/or product descriptions contained herein. The customer is urged to perform its own engineering review before deciding on a particular application. Micro Linear assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear products including liability or warranties relating to merchantability, fitness for a particular purpose, or infringement of any intellectual property right. Micro Linear products are not designed for use in medical, life saving, or life sustaining applications.

26

DS2111-01

Micro Linear Corporation ML2111CCS, ML2111CIP, ML2111CCP Datasheet

Specifications and Main Features

Frequently Asked Questions

User Manual