Cirrus Logic CS3301A User Manual

CS3301A

Low-noise, Programmable Gain, Differential Amplifier

Features & Desription

z Signal Bandwidth: DC to 2 kHz z Selectable Gain: x1, x2, x4, x8, x16, x32, x64 z Differential Inputs, Differential Outputs

• Multiplexed inputs: INA, INB, 800Ω termination

• Rough / fine outputs for CS5371A / 72A / 73A

• Max signal amplitude: 5 V

• Low input bias: 1 nA typical

Outstanding Noise Performance

nV/ Hz

• 8.5 from 0.1 Hz to 2 kHz

•0.180µV

Low Total Harmonic Distortion

• -121 dB THD typical (0.0000891%)

• -112 dB THD maximum (0.0002512%)

Low Power Consumption

• Normal operation: 5.5 mA typical

• Power down: 10 µA typical

Small 24-pin SSOP Package

z Bipolar Power Supply Configuration

• VA+ = +2.5 V; VA- = -2.5 V; VD = +3.3 V

between 0.1 Hz and 10 Hz

p-p

differential

Description

The CS3301A is a low-noise differential input, differential output amplifier with programmable gain, optimized for amplifying signals from low-impedance sensors such as geophones. The gain settings are binary weighted (x1, x2, x4, x8, x16, x32, x64) and are selected using simple pin settings. Two sets of external inputs, INA and INB, simplify system design as inputs from a sensor and test DAC. An internal 800 Ω termination can also be selected for noise tests.

Amplifier noise performance is outstanding with a noise density of 8.5 over the 0.1 Hz to 2 kHz bandwidth. Distortion performance is also extremely good, typically -121 dB THD at x1 gain. Flat noise down to 0.1 Hz and low total harmonic distortion make this amplifier ideal for low-frequency, low-amplitude, differential signals requiring maximum dynamic range.

ORDERING INFORMATION

See page 15.

nV/ Hz

http://www.cirrus.com

INA+ INB+

MUX0 MUX1

INAINB-

VA+

400 Ω 400 Ω

VA-

CLK

PWDN

OUTR+ OUTF+

GAIN0 GAIN1 GAIN2

OUTFOUTR-

GND

MAR ‘07

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1. CHARACTERISTICS AND SPECIFICATIONS .............................................................................. 3

SPECIFIED OPERATING CONDITIONS ....................................................................................... 3

ABSOLUTE MAXIMUM RATINGS ................................................................................................. 3

TEMPERATURE CONDITIONS ........ .... ... ... ... ... .... ... .......................................... ... ... .... ... ..............3

ANALOG CHARACTERISTICS ..................................................................................................... 4

DIGITAL CHARACTERISTICS ......................................................................................................7

POWER SUPPLY CHARACTER ISTICS ................... ....................... ................... ................... ........ 8

2. GENERAL DESCRIPTION ............................................................................................................. 9

2.1.Analog Signals................. .... .......................................... ... ... ... ..................................................9

2.2.1. Analog Inputs................................................................................................................9

2.3.2. Analog Outputs.............................................................................................................9

2.4.3. Differential Signals............ .... ... ... ... ... .... .......................................... ... ... ... .... ... ... ... ... ...10

2.5.Digital Signals.........................................................................................................................10

2.6.1. Clock Input..................................................................................................................10

2.7.2. Gain Selection ............................................................................................................10

2.8.3. Mux Selection .............................................................................................................10

2.9.4. Power Down Selection...... .... ... ... ... ... .... ... ................................................................... 11

2.10.Power Supplies .............. .... ... ... ... .... ... ... .......................................... ... ... .... ... .........................11

2.11.1. Analog Power Supplies...............................................................................................11

2.12.2. Digital Power Supplies................................................................................................11

2.13.Connection Diagram..............................................................................................................12

3. PIN DESCRIPTION.......................................................................................................................13

4. PACKAGE DIMENSIONS...... .... ... ... .......................................... ... .... ... ... ... ... .... ... .........................14

5. ORDERING INFORMATION ........................................................................................................ 15

6. ENVIRONMENTAL, MANUFACTURING, & HANDLING INFORMATION .................................. 15

7. REVISION HISTORY ................................................... ... .... ... .......................................... ... ......... 16

CS3301A

LIST OF FIGURES

Figure 1. CS3301A Noise Performance..........................................................................................4

Figure 2. Digital Input Rise and Fall Times .....................................................................................7

Figure 3. Multi-Channel System Architecture.................................................................................. 9

Figure 4. Single-Channel System Architecture ............................................................................. 10

Figure 5. CS3301A Amplifier Connections....................................................................................12

Figure 6. CS3301A Pin Assignments............................................................................................13

LIST OF TABLES

Table 1. Digital Selections for Gain and Input Mux Control . ...........................................................7

Table 2. Pin Descriptions .............................................................................................................13

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CS3301A

1. CHARACTERISTICS AND SPECIFICATIONS

• Min / Max characteristics and specifications are guaranteed over the Specified Operating Conditions.

• Typical performance characteristics and specifications are measured at nominal supply voltages and T

• GND = 0 V. Single-ended voltages with respect to GND, differential voltages with respect to opposite half.

• Device is connected as shown in Figure 5 on page 12 unless otherwise noted.

SPECIFIED OPERATING CONDITIONS

Parameter Symbol Min Nom Max Unit

Bipolar Power Supplies

Positive Analog ± 2 % VA+ 2.45 2.50 2.55 V Negative Analog (Note 1) ± 2% V A- -2.55 -2.50 -2.45 V Positive Digital (Note 2) ± 3% VD 3.20 3.30 3.40 V

Thermal

Ambient Operating Temperature Industrial (-IS, -ISZ) T

Notes: 1. VA- must be the most negative voltage to avoid potential SCR latch-up conditions.

2. VD must conform to Digital Supply Differential under Absolute Maximum Ratings.

-40 25 85 °C

= 25°C.

ABSOLUTE MAXIMUM RATINGS

Parameter Symbol Min Max Parameter

DC Power Supplies Positive Analog

Negative Analog

Digital Analog Supply Differential [(VA+) - (VA-)] VA Digital Supply Differential [(VD) - (VA-)] VD Input Current, Power Supplies (Note 3)I Input Current, Any Pin Except Supplies (Note 3)I Output Current (Note 3)I

VA+

VA-

DIFF DIFF

PWR

OUT

-0.5

-6.8

-0.5

6.8

0.5

6.8

V V V

-6.8V

-±50mA

-±10mA

-±25mA Power Dissipation PD - 500 mW Analog Input Voltages V Digital Input Voltages V Storage Temperature Range T

INA IND

STG

(VA-) - 0.5 (VA+) + 0.5 V

-0.5 (VD) + 0.5 V

-65 150 ºC

WARNING: Operation at or beyond these limits may result in permanent damage to the device.

Normal operation is not guaranteed at these extremes.

Notes: 3. Transient currents up to ±100 mA will not cause SCR latch-up.

TEMPERATURE CONDITIONS

Parameter Symbol Min Typ Max Unit

Ambient Operating Temperature T Storage Temperature Range T Allowable Junction Temperature T Junction to Ambient Thermal Impedance Θ

A STR JCT

-40 - 85 ºC

-65 - 150 ºC

--125ºC

ºC / W

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ANALOG CHARACTERISTICS

CS3301A

Parameter Symbol

Noise Performance

Input Voltage Noise f Input Voltage Noise Density f0 = 0.1 Hz to 2 kHz VN Input Current Noise Density (Note 4)IN

Distortion Performance

Total Harmonic Distortion (Note 5)x1 x2

Linearity (Note 5)x1

= 0.1 Hz to 10 Hz VN

x8 x16 x32 x64

THD

LIN

-0.18 0.40µV

-8.5 12.0

-100 -

-121

-120

-119

-116

0.0000891

0.0001000

0.0001122

0.0001585

CS3301A

-112

0.0002512

UnitMin Typ Max

p-p

nV/ Hz

fA/ Hz

Notes: 4. Guaranteed by design and/or characterization.

5. Tested with a full scale input signal of 31.25 Hz.

CS3301A In-Band Noise

Noise Density (nV/rtHz)

0 200 4 00 600 800 1000 1200 1400 1600 1800 2000

Frequency (Hz)

CS3301A Wide Band Noise

300 250 200 150 100

Noise Density (nV/rtHz)

0.1 1 10 100 10 00 10000 100000 1E+06

Frequency (Hz)

Figure 1. CS3301A Noise Performance

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CS3301A

ANALOG CHARACTERISTICS (CONT.)

CS3301A

Parameter Symbol

Gain

Gain, Differential GAIN x1 - x64 Gain, Common Mode (Note 6)GAIN Gain Accuracy, Absolute (Note 7)GAIN

ABS

Gain Accuracy, Relative (Note 8)2x

-x1-

-±1±2%

-0.4 -0.2 0 4x - -0.2 8x - -0.2 -

GAIN

16x - -0.2 -

REL

32x - -0.3 64x - -0.3 -

Gain Drift (Note 4, 9)GAIN

-5-ppm/ºC

Offset

Offset Voltage, Input Referred (Note 10) OFST - ±5 ±15 µV Offset After Calibration, Absolute (Note 11)OFST Offset Calibration Range (Note 12)OFST Offset Voltage Drift (Note 4, 9)OFST

CAL

RNG

-±1-µV

-100-% FS

-0.1-µV/ºC

UnitMin Typ Max

6. Common mode signals pass unchanged through the differential amplifier ar chitecture and are re jected by the CS5371A / 72A / 73A modulator CMRR.

7. Absolute gain accuracy tests the matching of x1 gain across multiple CS3301A devices.

8. Relative gain accuracy tests the tracking of x2, x4, x8, x16, x32, x64 gain relative to x1 gain on a single CS3301A device.

9. Specification is for the parameter over the specified temperature range and is for the CS3301A device only. It does not include the effects of external components.

10. Offset voltage is tested with the amplifier inputs connected to the internal 800 Ω termination.

11. The absolute offset after calibration specification applies to the effective offset voltage of the CS33 01A output when used with the CS5371A / 72A / 73A modulator and CS5376A / 78 digital filter, and is measured from the digitally calibrated output codes of the digital filter.

12. The CS3301A offset calibration is performed digitally with the CS5371A / 72A / 73A modulator and CS5376A / 78 digital filter and includes the full scale signal range. Calibration offsets of greater than ± 5% of full scale will begin to subtract from system dynamic range.

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+ 11 hidden pages

Cirrus Logic CS3301A User Manual

Features & Desription

TABLE OF CONTENTS

LIST OF FIGURES

LIST OF TABLES

1. CHARACTERISTICS AND SPECIFICATIONS

SPECIFIED OPERATING CONDITIONS

ABSOLUTE MAXIMUM RATINGS

TEMPERATURE CONDITIONS