NSC LM4548VHX, LM4548VH Datasheet

LM4548 AC ’97 Rev 2 Codec with Sample Rate Conversion and National 3D Sound

General Description

The LM4548 is an audio codec for PC systems which is fully PC98 compliant and performs the analog intensivefunctions of the AC97 Rev2 architecture. Using 18-bit Sigma-Delta A/D’s and D/A’s, the LM4548 provides 90dB of Dynamic Range.

The LM4548 was designed specifically to provide a high quality audiopathand provide all analog functionality in a PC audio system. It features full duplex stereo A/D’s and D/A’s and an analog mixer with 4 stereo and 3 mono inputs, each of which has separate gain, attenuation and mute control. The LM4548 also provides the additional True Line-Level output and National’s 3D Sound stereo enhancement.

The LM4548 supports variable sample rate conversion as defined in the AC97 Rev2 specification. The sample rate for the A/D and D/A can be programmed separately to convert any rate between 4kHz - 48kHz with a resolution of 1Hz. The AC97 architecture separates the analog and digital functions of the PC audio system allowing both for system design flexibility and increased performance.

Key Specifications

n Analog Mixer Dynamic Range 97dB (typ) n D/A Dynamic Range 89dB (typ) n A/D Dynamic Range 90dB (typ)

Features

n AC’97 Rev2 compliant n National’s 3D Sound circuitry n High quality Sample Rate Conversion (SRC) from 4kHz

to 48kHz in 1Hz increments.

n Multiple Codec Support n True Line Level Output with volume control in addition to

standard Line Out

n Advanced power management support n Digital 3V and 5V compliant

Applications

n Desktop PC Audio Systems n Portable PC Systems n Mobile PC Systems

Block Diagram

DS100987-1

FIGURE 1. LM4548 Block Diagram

February 1999

LM4548 AC ’97 Rev 2 Codec with Sample Rate Conversion and National 3D Sound

Absolute Maximum Ratings (Note 3)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

Supply Voltage 6.0V Storage Temperature −40˚C to +150˚C Input Voltage −0.3V to V

DD

+0.3V

ESD Susceptibility (Note 5) 2500V

pins 27, 28 1500V pin 3 750V

ESD Susceptibility (Note 6) 200V

pin 3 100V

Junction Temperature 150˚C

Soldering Information

TQFP Package Vapor Phase (60 sec.) 215˚C Infrared (15 sec.) 220˚C

See AN-450 ″Surface Mounting and their Effects on Product Reliability″ for other methods of soldering surface mount devices.

θ

JA

(typ)—VBH48A 74˚C/W

Operating Ratings

Temperature Range

T

MIN

≤ TA≤ T

MAX

−40˚C ≤ TA≤ 85˚C

Analog Supply Range 4.2V ≤ AV

DD

≤ 5.5V

Digital Supply Range 3.0V ≤ DV

DD

≤ 5.5V

Electrical Characteristics (Notes 1, 3)

The following specifications apply for AVDD= 5V, DVDD= 5V, Fs = 48kHz, single codec configuration, unless otherwise noted. Limits apply for TA= 25˚C. The reference for 0dB is 1Vrms unless otherwise specified.

Symbol Parameter Conditions

LM4548

Units

(Limits)

Typical

(Note 7)

Limit

(Note 8)

AV

DD

Analog Supply Range 4.2 V (min)

5.5 V (max)

DV

DD

Digital Supply Range 3.0 V (min)

5.5 V (max)

D

IDD

Digital Quiescent Power Supply Current

D

VDD

=5V 43 mA

D

VDD

= 3.3V 20 mA

A

IDD

Analog Quiescent Power Supply Current

53 mA

I

DSD

Digital Shutdown Current 500 µA

I

ASD

Analog Shutdown Current 30 µA

V

REF

Reference Voltage 2.23 V

PSRR Power Supply Rejection Ratio 40 dB

Analog Loopthru Mode

Dynamic Range (Note 2)

CD Input to Line Output, -60dB Input THD+N, A-Weighted

97 90 dB (min)

THD Total Harmonic Distortion V

O

= -3dB, f = 1kHz, RL= 10kΩ 0.01 0.02

%

(max)

Analog Input Section

V

IN

Line Input Voltage 1 Vrms Mic Input with 20dB Gain 0.1 Vrms

Mic Input with 0dB Gain 1 Vrms Xtalk Crosstalk CD Left to Right -95 dB Z

IN

Input Impedance(Note 2) 40 10 kΩ (min) C

IN

Input Capacitance 15 pF

Interchannel Gain Mismatch CD Left to Right 0.01 dB

Record Gain Amplifier - A/D

A

S

Step Size 0dB to 22.5dB 1.5 dB

Mixer Section

A

S

Step Size +12dB to -34.5dB 1.5 dB A

M

Mute Attenuation 86 dB

Analog to Digital Converters

Resolution 18 Bits

www.national.com 2

Electrical Characteristics (Notes 1, 3) (Continued)

The following specifications apply for AVDD= 5V, DVDD= 5V, Fs = 48kHz, single codec configuration, unless otherwise noted. Limits apply for TA= 25˚C. The reference for 0dB is 1Vrms unless otherwise specified.

Symbol Parameter Conditions

LM4548

Units

(Limits)

Typical

(Note 7)

Limit

(Note 8)

Analog to Digital Converters

Dynamic Range (Note 2) -60dB Input THD+N, A-Weighted 90 86 dB (min) Frequency Response -1dB Bandwidth 20 kHz

Digital to Analog Converters

Resolution 18 Bits Dynamic Range (Note 2) -60dB Input THD+N, A-Weighted 89 85 dB (min)

THD Total Harmonic Distortion V

IN

= -3dB, f=1kHz, RL= 10kΩ 0.01

% Frequency Response 20 - 21k Hz Group Delay (Note 2) 2 mS (max) Out of Band Energy -40 dB Stop Band Rejection 70 dB

D

T

Discrete Tones -96 dB

True Line Level Output Volume Section

A

S

Step Size 0dB to -46.5dB 1.5 dB

A

M

Mute Attenuation 86 dB

Digital I/O (Note 2) V

IL

Low level input voltage

0.30 x DVDD

V (max)

V

HI

High level input voltage

0.40 x DVDD

V (min)

V

OH

High level output voltage

0.50 x DVDD

V (min)

V

OL

Low level output voltage

0.20 x DVDD

V (max)

I

L

Input Leakage Current AC Link inputs

±

10 µA

I

L

Tri state Leakage Current High impedance AC Link outputs

±

10 µA

I

DR

Output drive current AC Link outputs 5 mA

Digital Timing Specifications (Note 2) F

BC

BIT_CLK frequency 12.288 MHz

T

BCP

BIT_CLK period 81.4 nS

T

CH

BIT_CLK high

Variation of BIT_CLK period from 50

%

duty cycle

±

20

%

(max)

F

SYNC

SYNC frequency 48 kHz

T

SP

SYNC period 20.8 µS

T

SH

SYNC high pulse width 1.3 µS

T

SL

SYNC low pulse width 19.5 µS

T

SETUP

Setup Time

SDATA_IN, SDATA_OUT to falling edge of BIT_CLK

15 nS (min)

T

HOLD

Hold Time

Hold time of SDATA_IN, SDATA_OUT from falling edge of BIT_CLK

5 nS (min)

T

RISE

Rise Time

BIT_CLK, SYNC, SDATA_IN or SDATA_OUT

6 nS (max)

T

FALL

Fall Time

BIT_CLK, SYNC, SDATA_IN or SDATA_OUT

6 nS (max)

T

RST_LOW

RESET# active low pulse width For cold reset 1.0 µS (min)

T

RST2CLK

RESET# inactive to BIT_CLK start up

For cold reset 162.8 nS (min)

www.national.com3

Electrical Characteristics (Notes 1, 3) (Continued)

The following specifications apply for AVDD= 5V, DVDD= 5V, Fs = 48kHz, single codec configuration, unless otherwise noted. Limits apply for TA= 25˚C. The reference for 0dB is 1Vrms unless otherwise specified.

Symbol Parameter Conditions

LM4548

Units

(Limits)

Typical

(Note 7)

Limit

(Note 8) Digital Timing Specifications (Note 2) T

SH

SYNC active high pulse width For warm reset 1.3 µS

T

SYNC2CLK

SYNC inactive to BIT_CLK start up For warm reset 162.8 nS (min)

T

SU2RST

Setup to trailing edge of RESET# For ATE Test Mode 15 nS (min)

T

RST2HZ

Rising edge of RESET# to Hi-Z For ATE Test Mode 25 nS (max)

Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified. Note 2: These specifications are guaranteed by design and characterization; they are not production tested. Note 3:

Absolute Maximum Ratings

indicate limits beyond which damage to the device may occur.

Operating Ratings

indicate conditions for which the device is func-

tional, but do not guarantee specific performance limits.

Electrical Characteristics

state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance.

Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by T

JMAX

, θJA, and the ambient temperature TA. The maximum

allowable power dissipation is P

DMAX

=(T

JMAX–TA

)/θJAor the number given in Absolute Maximum Ratings, whichever is lower. For the LM4548, T

JMAX

= 150˚C. The

typical junction-to-ambient thermal resistance is 74˚C/W for package number VBH48A.

Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor.

Note 6: Machine Model, 220 pF–240 pF discharged through all pins. Note 7: Typicals are measured at 25˚C and represent the parametric norm. Note 8: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

www.national.com 4

Timing Diagrams

Clocks

DS100987-10

Data Setup and Hold

DS100987-11

Digital Rise and Fall

DS100987-12

Cold Reset

DS100987-13

Warm Reset

DS100987-14

www.national.com5

Typical Application

DS100987-3

FIGURE 2. LM4548 Typical Application Circuit

www.national.com 6