LINEAR TECHNOLOGY LTC1564 Technical data

FEATURES

LTC1564

10kHz to 150kHz

Digitally Controlled

Antialiasing Filter and 4-Bit P.G.A.

U

DESCRIPTIO

■

4-Bit Digitally Controlled 8th-Order Lowpass Filter
–f

Adjustable from 10kHz to 150kHz in 10kHz

CUTOFF

Steps

– 100dB Attenuation at 2.5 × f

■

4-Bit Digitally Controlled Programmable Gain

CUTOFF

Amplifier
– G = 1 to 16 in 1V/V Steps

■

Miniature 16-Pin SSOP Package

■

No External Components

■

122dB Total System Dynamic Range

■

Rail-to-Rail Input and Output Range

■

2.7V to 10V Operation

■

Low Noise Mute Mode

■

Low Power Shutdown Mode

■

Available in 16-Lead Plastic SSOP Package

U

APPLICATIO S

■

Antialias or Reconstruction Filtering

■

DSP Systems

■

Communications Systems

■

Scientific Instruments

■

High Resolutions (16 Bits to 20 Bits)

■

Processing Signals Buried in Noise

■

Audio Signal Processing

■

Programmable Data Rates

■

Automatic Gain Control (AGC)

■

Single Part Replacing Multiple Filters

The LTC®1564 is a new type of continuous time filter for
antialiasing, reconstruction and other band-limiting appli­cations. No other analog components or filter expertise are
needed to use it. There is one analog input pin and one
analog output pin. The cutoff frequency (f

) and gain are

C

programmable while the shape of the lowpass response is
fixed. A latching digital interface stores f

and gain settings

C

or it can be bypassed for control directly from the pins. The
LTC1564 operates from 2.7V to 10V total (single or split
supplies) and comes in a 16-pin surface mount SSOP.

The LTC1564 is a rail-to-rail high resolution 8th-order
lowpass filter with two stopband notches, giving approxi­mately 100dB attenuation at 2.5 times the passband cutoff
frequency fC (a de-facto standard for DSP front ends).
Signals with low or variable levels can be normalized with
the built-in variable gain that reduces input-referred noise
with increasing gain for a typical dynamic range (maxi­mum signal level to minimum noise) of 122dB (20 equiva­lent bits) with 20kHz fC and 118dB at 100kHz fC on a ±5V
supply.

Other frequency-response shapes can be provided upon
request. Please contact LTC Marketing.

, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.

TYPICAL APPLICATIO

Low Noise Programmable Filter with Variable Gain

ANALOG

IN

IN AGND V+RST G3

OUT V

ANALOG

OUT

+

V

0.1µF

GAIN CODE

16 15 14 13 12 11

–

EN

HOLD F3 F2 F1 F0

1234567

0.1µF

–

V

G2 G1 G0

LTC1564

CS/

FREQUENCY CODE

1564 TA01

U

10 9

+

V

AND V– SUPPLIES CAN BE FROM

1.35V TO 5.25V EACH
TIE F AND G PINS TO V

SET FREQUENCY AND GAIN
DYNAMIC RANGE 118dB TO 122dB

AT ± 5V DEPENDING ON FREQUENCY CODE

8

+

OR V– TO

LTC1564 Programmable Range

30
20
10

0
–10
–20
–30
–40
–50

GAIN (dB)

–60
–70
–80
–90

–100
–110
–120

5

fC = 10kHz

GAIN = 1V/V

10 100 500

fC = 150kHz

GAIN = 16V/V

FREQUENCY (kHz)

1564 TA02

1564fa

1

LTC1564

G PACKAGE

16-LEAD PLASTIC SSOP

1

2

3

4

5

6

7

8

TOP VIEW

16

15

14

13

12

11

10

9

OUT

V

–

EN

CS/HOLD

F3

F2

F1

F0

IN

AGND

V

+

RST

G3

G2

G1

G0

WWWU

ABSOLUTE AXI U RATI GS

(Note 1)

Total Supply Voltage (V+ to V–) .............................. 11V

Input Voltage ............................. V

Output Short-Circuit Duration .......................... Indefinite

Operating Temperature Range

LTC1564C .............................................. 0°C to 70°C

LTC1564I.......................................... –40°C TO 85°C

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

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

+

+ 0.3V to V– – 0.3V

UU

W

PACKAGE/ORDER I FOR ATIO

ORDER PART

NUMBER

LTC1564CG
LTC1564IG

T

= 125°C, θJA = 130°C/ W

JMAX

Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF

Lead Free Part Marking: http://www.linear.com/leadfree/

Consult LTC Marketing for parts specified with wider operating temperature ranges.

ELECTRICAL CHARACTERISTICS

range, otherwise specifications are at T

PARAMETER CONDITIONS MIN TYP MAX UNITS

Total Supply Voltage 2.7 10.5 V

Supply Current VS = ±1.35V, VIN = 0V

Output Voltage Swing RL = 10k to 0V

Output Short-Circuit Current VS = ±5V

DC Offset Voltage Magnitude (Referred to Input) Gain = 1, 0°C to 70°C

DC AGND Reference Voltage VS = Single 5V Supply 2.5 V

Passband Gain fC = 50kHz, fIN = 10kHz, Gain = 1

Passband Ripple fC = 10kHz, 0 ≤ fIN ≤ 9kHz (Notes 2, 3)

Roll Off at Cutoff Frequency (fC) (Note 3) fC = 10kHz (F = 0001)

Roll Off at 2fC (Note 3) fC = 10kHz

Roll Off at 2.5fC (Note 3) fC = 10kHz –99 dB

Wideband Noise (Referred to Input) BW = 20kHz, fC = 10kHz, Gain = 1 33 µV

Total Harmonic Distortion fC = 100kHz, fIN = 10kHz, VIN = 1V

2

= 25°C. VS = ± 2.375V, fC = 10kHz, gain = 1, RL = 10k, unless otherwise noted.

A

V
V

Gain = 1, – 40°C to 85°C
Gain = 10, 0°C to 70°C
Gain = 10, –40°C to 85°C

f

C

f

C

f

C

BW = 20kHz, fC = 10kHz, Gain = 16 2.5 µV
BW = 200kHz, fC = 100kHz, Gain = 1 50 µV

The ● denotes specifications that apply over the full operating temperature

= ±2.375V, VIN = 0V

S

= ±5V, VIN = 0V

S

= 50kHz, fIN = 10KHz, Gain = 16

= 150kHz, 0 ≤ fIN ≤ 135kHz (Notes 2, 3)

= 150kHz (F = 1111)

RMS

●

●

●

●

4.5 4.65 V

●

●

●

●

●

●

– 0.1 0.3 0.8 dB

●

23.5 24.2 25.3 dB

●

–0.5 0.5 dB

●

– 0.6 1.6 dB

●

–1.2 –0.7 –0.3 dB

●

–1.5 –0.5 0.6 dB

●

–67 –63 –59 dB

15 17 mA
16 18.5 mA
22 25 mA

±10 mA

313 mV
316 mV
15 mV
16 mV

–86 dB

P-P

RMS
RMS
RMS

1564fa

LTC1564

FREQUENCY (kHz)

50

–10

GAIN (dB)

–5

0

85°C

5

62.5 75 87.5 100

1564 G03

112.5

125

fC = 100kHz
SINGLE 5V SUPPLY

–40°C

25°C

ELECTRICAL CHARACTERISTICS

range, otherwise specifications are at T

= 25°C. VS = ± 2.375V, fC = 10kHz, gain = 1, RL = 10k, unless otherwise noted.

A

The ● denotes specifications that apply over the full operating temperature

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Impedance Gain = 1, DC VIN = 0V 10 kΩ

Gain = 16, DC V

= 0V 625 Ω

IN

Output Impedance fC = 10kHz, f = 10kHz 30 Ω

Mute State (F = 0000) Gain F = 0000, fIN = 20kHz, VIN = 1V

RMS

Mute State Output Noise F = 0000, BW = 200kHz 5.4 µV

Shutdown Supply Current VS = ±1.35V, EN to V

= ±1.35V, EN to V

V

S

VS = ±2.375V, EN to V
V

= ±2.375V, EN to V

S

+
+

+
+

●

●

–103 dB

RMS

45 75 µA

150 µA

100 150 µA

180 µA

VS = ±5V, EN to V+ (Note 4) 175 µA

Digital Input “High” Voltage VS = ±1.35V 1.08 V

V

= ±2.375V 1.90 V

S

= ±5V 4.50 V

V

S

Digital Input “Low” Voltage VS = ±1.35V –1.08 V

= ±2.375V –1.90 V

V

S

V

= ±5V 0.50 V

S

Digital Input Pull-Up or Pull-Down Current (Note 5) VS = ±1.35V
(Digital Inputs Other than EN) V

= ±5V

S

Digital Input Pull-Up Current (EN Input) VS = ±1.35V

= ±5V

V

S

Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.

Note 2: Response is tested in production at discrete frequencies f

0.5, 0.8 and 0.9 times f

.

C

of 0.1,

IN

Note 3: Relative to gain at 0.1fC.
Note 4: All digital inputs driven rail-to-rail. When driving digital inputs with

Note 5: Each digital input includes a small positive or negative current

source to float the CMOS input to V
The table shows the current due to this source when the input is driven at
the supply voltage opposite from the float potential. Pins CS/HOLD, F3, F2,
F0 and G3 to G0 float to the V
voltage. See “Floatable Digital Inputs” in Applications Information section.

●

●

●

●

+

or V– potential if it is unconnected.

–

voltage, pins RST, EN and F1 to the V

3.5 6 µA
13 20 µA

12 µA

10 20 µA

+

0V and 5V levels, the shutdown current will increase to 3.5mA (typ).

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Overall Frequency Response
(Frequency Scales Normalized to f

10

0
–10
–20
–30
–40
–50
–60
–70

GAIN (dB)

–80
–90

–100
–110
–120
–130

0.1

fC = 50kHz

fC = 10kHz

1

fIN/f

C

VS = SINGLE 5V
UNITY GAIN
(G CODE 0000)

fC = 150kHz

1564 G01

)

C

10

Roll-Offs Over Temperature
(fC = 10kHz)

5

fC = 10kHz
SINGLE 5V SUPPLY

0

GAIN (dB)

–5

–10

5

–40°C, 25°C, 85°C

6.25 7.5 8.75 10
FREQUENCY (kHz)

11.25

Roll-Offs Over Temperature
(fC = 100kHz)

12.5

1564 G02

1564fa

3

LTC1564

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Passband Roll-Off at fIN = f
vs f

0

VS = SINGLE 5V
T

A

–0.25

–0.50

–0.75

GAIN (dB)

–1.00

–1.25

–1.50

10

Detail of Stopband Response

–40

–50

–60

–70

–80

–90

GAIN (dB)

–100

–110

–120

–130

–140

25

15

35

FREQUENCY (kHz)

C

= 25°C

30 50

45

70 110

fC = 10kHz

= ±5V

V

S

= 25°C

T

A

55

1564 G05

90 130 150

fC (kHz)

65

C

1564 G04

Rectangular Pulse Response Short-Pulse Response

2V/DIV

Triangular-Wave Time Response SNR vs Input Voltage

5V/DIV

INPUT

OUTPUT

200µs/DIV

fC = 10kHz

= 1kHz

f

IN

UNITY GAIN

= ± 5V

V

S

1564 G09

140
130
120
110
100

90
80
70
60
50

SIGNAL/NOISE (dB)

40
30
20
10

LIMIT FOR 10V TOTAL SUPPLY

LIMIT FOR 5V TOTAL SUPPLY

GAIN = 16

= 100kHz

f

C

GAIN = 16

= 20kHz

f

C

0

0.001 0.1 1 10

0.01
INPUT VOLTAGE (V

200µs/DIV

GAIN = 1
f

Passband Gain, Phase
and Group Delay

5

f

= 10kHz

C

0

–5

–10

–15

–20

GAIN (dB)

–25

–30

–35

–40

–45

f
UNITY GAIN
V

INPUT

OUTPUT

GAIN = 1

= 100kHz

f

C

= 20kHz

C

PASSBAND INPUT

< fC)

(f

IN

)

P-P

2

= 10kHz

C

= ±5V

S

4

1564 G07

1564 G10

GAIN

GROUP DELAY

6

FREQUENCY (kHz)

(THD + NOISE)/SIGNAL (dB)

–100

500

90

450

0

400

–90

PHASE (DEGREES)

350

PHASE

8

10

INPUT, 1V/DIV (PULSE WIDTH 10µs)

–180

300

–270

250

–360

200

–450

150

–540

100

–630

50

–720

0

–810

12

1546 G06

OUTPUT, 100mV/DIV

100µs/DIV

DELAY (µs)

fC = 10kHz
UNITY GAIN

= ± 5V

V

S

THD + Noise vs Input Voltage

= 10kHz)

(f

C

–20

–30

–40

–50

–60

–70

–80

–90

fC = 10kHz

= 1kHz

f

IN

0.001 0.1 1 10

0.01
INPUT VOLTAGE (V

3V SUPPLY

5V SUPPLY

±5V SUPPLY

)

P-P

1564 G08

1564 G11

4

1564fa