5

PCM1840

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SBAS989 – APRIL 2019

Product Folder Links: PCM1840

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Copyright © 2019, Texas Instruments Incorporated

(1)

For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application

report.

6.4 Thermal Information

THERMAL METRIC(1)

PCM1840

UNIT

RTW (WQFN)

24 PINS

RθJA

Junction-to-ambient thermal resistance

32.6

°C/W

RθJC(top)

Junction-to-case (top) thermal resistance

25.0

°C/W

RθJB

Junction-to-board thermal resistance

11.9

°C/W

ψJT

Junction-to-top characterization parameter

0.2

°C/W

ψJB

Junction-to-board characterization parameter

11.9

°C/W

RθJC(bot)

Junction-to-case (bottom) thermal resistance

2.9

°C/W

(1)

Ratio of output level with 1-kHz full-scale sine-wave input, to the output level with the AC signal input shorted to ground, measured A-

weighted over a 20-Hz to 20-kHz bandwidth using an audio analyzer.

(2)

All performance measurements done with 20-kHz low-pass filter and, where noted, A-weighted filter. Failure to use such a filter may

result in higher THD and lower SNR and dynamic range readings than shown in the Electrical Characteristics. The low-pass filter

removes out-of-band noise, which, although not audible, may affect dynamic specification values.

(3)

For best distortion performance, use input AC-coupling capacitors with low-voltage-coefficient.

6.5 Electrical Characteristics

at TA = 25°C, AVDD = 3.3 V, IOVDD = 3.3 V, fIN = 1-kHz sinusoidal signal, fS = 48 kHz, 32-bit audio data, BCLK = 256 × fS,

TDM slave mode (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

ADC CONFIGURATION

AC input impedance

Input pins INxP or INxM

2.5

kΩ

ADC PERFORMANCE FOR LINE/MICROPHONE INPUT RECORDING : AVDD 3.3-V OPERATION

Differential input full-scale

AC signal voltage

AC-coupled input

2

VRMS

SNR

Signal-to-noise ratio, A-

weighted(1)(2)

IN1 differential input selected and AC signal shorted to

ground, DRE enabled (DRE_LVL = –36 dB,

DRE_MAXGAIN = 24 dB)

115

122

dB

IN1 differential input selected and AC signal shorted to

ground, DRE disabled

106

112

DR

Dynamic range, A-

weighted(2)

IN1 differential input selected and –60-dB full-scale AC

signal input, DRE enabled (DRE_LVL = –36 dB,

DRE_MAXGAIN = 24 dB)

123

dB

IN1 differential input selected and –60-dB full-scale AC

signal input, DRE disabled

113

THD+N

Total harmonic

distortion(2)(3)

IN1 differential input selected and –1-dB full-scale AC

signal input, DRE enabled (DRE_LVL = –36 dB,

DRE_MAXGAIN = 24 dB)

–98

–80

dB

IN1 differential input selected and –1-dB full-scale AC

signal input, DRE disabled

–98

ADC OTHER PARAMETERS

Output data sample rate

7.35

192

kHz

Output data sample word

length

32

Bits

Interchannel isolation

–1-dB full-scale AC-signal input to non measurement

channel

–124

dB

Interchannel gain

mismatch

–6-dB full-scale AC-signal input

0.1

dB

Gain drift

across temperature range 15°C to 35°C

–4.4

ppm/°C

Interchannel phase

mismatch

1-kHz sinusoidal signal

0.02

Degrees

Phase drift

1-kHz sinusoidal signal, across temperature range 15°C

to 35°C

0.0005

Degrees/°C

PSRR

Power-supply rejection

ratio

100-mVPP, 1-kHz sinusoidal signal on AVDD, differential

input selected, 0-dB channel gain

102

dB

CMRR

Common-mode rejection

ratio

Differential microphone input selected, 100-mVPP, 1-kHz

signal on both pins and measure level at output

60

dB