19-3454; Rev 3; 4/06
KIT
ATION
EVALU
BLE
AVAILA
Stereo Audio DAC with DirectDrive
Headphone Amplifier
Features
♦
1.8V to 3.6V Single-Supply Operation
♦
30mW Stereo Headphone Output Power with
1.8V Supply
♦
DirectDrive Outputs Eliminate DC-Blocking
Capacitors
♦
91dB PSRR at 1kHz
♦
Any Master Clock Up to 40MHz
♦
Flexible I
2
S-Compatible Digital Audio Interface
♦
I
2
C Headphone Volume and Mute Control
♦
Stereo Line Inputs and Outputs
♦
Clickless/Popless Operation
♦
2-Wire (I
2
C)-Compatible Control Interface
♦
Available in 28-Pin Thin QFN Package
General Description
The MAX9850 is a low-power, high-performance stereo
audio DAC with an integrated DirectDrive headphone
amplifier. The MAX9850 is designed to meet the board
space and performance requirements of portable devices
such as cell phones and MP3 and portable DVD players.
The MAX9850 uses Maxim’s DirectDrive headphone
technology that produces a ground-biased analog
audio output from a single supply, which allows for dri-
ving the headphones directly from the amplifier outputs
without large DC-blocking capacitors. This feature
saves board space, provides higher click/pop suppres-
sion, and improves low-frequency (bass) response. The
architecture does not require the headphone jack to be
biased to a DC voltage and thus allows for a conven-
tional, grounded chassis design.
The MAX9850’s flexible clocking circuitry utilizes any
available system clock up to 40MHz, eliminating the
need for an external PLL and multiple crystal oscillators.
The DAC supports a wide range of sample rates from
8kHz to 48kHz in both master and slave modes, making
the MAX9850 the easiest to use and most versatile audio
DAC available. It can also be operated like traditional
synchronous DACs, at any integer-oversampling ratio.
The audio DAC receives input data over a flexible
3-wire interface that supports left-justified, right-justified
audio data, or I
2
S-compatible audio data. Stereo audio
line inputs are provided to either mix analog audio with
the digital input stream, or to drive the headphone out-
puts directly. Mode settings, headphone amplifier vol-
ume controls, and shutdown for both the headphone
and line outputs are programmed through a 2-wire,
I
2
C-compatible interface.
The MAX9850 is fully specified over the -40°C to +85°C
extended temperature range and is available in a low-
profile, 28-pin thin QFN package (5mm x 5mm x 0.8mm).
MAX9850
Ordering Information
PART
MAX9850ETI+
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
28 TQFN-EP**
PKG
CODE
T2855-6
**EP
= Exposed pad.
+Denotes
lead-free package.
Pin Configuration appears at end of data sheet.
Block Diagram
MCLK
1.8V TO 3.6V
INR
Applications
MP3/Portable Multimedia Players
Cell Phones/Smart Phones
Portable DVD Players
SDIN
BCLK
LRCLK
SDA
SCL
ADD
GPIO
DIGITAL
PLL
MAX9850
DAC
OUTR
LINE
OUT
DIGITAL
AUDIO
DAC
+
+
INL
HPR
HPL
OUTL
I
2
C
LINE
OUT
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Stereo Audio DAC with DirectDrive
Headphone Amplifier
MAX9850
ABSOLUTE MAXIMUM RATINGS
(Voltages with respect to AGND.)
DV
DD
, AV
DD
, PV
DD
..................................................-0.3V to +4V
AV
DD
Referenced to PV
DD
....................................-0.3V to +0.3V
SV
SS
, PV
SS
...............................................................-4V to +0.3V
SV
SS
Referenced to PV
SS
.....................................-0.3V to +0.3V
DGND, PGND........................................................-0.3V to +0.3V
BCLK, LRCLK, HPS, SDIN.......................-0.3V to (DV
DD
+ 0.3V)
GPIO, MCLK.............................................................-0.3V to +4V
REF, PREG ...............................................-0.3V to (AV
DD
+ 0.3V)
NREG ........................................................+0.3V to (SV
SS
- 0.3V)
SDA, SCL, ADD ........................................................-0.3V to +4V
INL, INR .......................................................................-2V to +2V
HPR, HPL.....................................(SV
SS
- 0.3V) to (AV
DD
+ 0.3V)
OUTL, OUTR .............................(NREG - 0.3V) to (PREG + 0.3V)
C1N ............................................(PV
SS
- 0.3V) to (PGND + 0.3V)
C1P ............................................(PGND - 0.3V) to (PV
DD
+ 0.3V)
Current Into/Out of Any Pin ...............................................100mA
Duration of HPL, HPR, OUTL,
OUTR Short Circuit to AGND .................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
28-Pin Thin QFN (derate 35.7mW/°C above +70°C) .....2857mW
Junction Temperature ......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(DV
DD
= AV
DD
= PV
DD
= 3.0V, AGND = DGND = PGND = 0V, C1 = 0.47µF, C2 = 2.2µF, C
NREG
= C
PREG
= C
REF
= 1µF to AGND,
R
LOAD_HP
= 32Ω to AGND, R
LOAD_OUT
= 10kΩ to AGND, f
LRCLK
= 48kHz, f
MCLK
= 12.288MHz, volume set to -9.5dB, T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical specifications at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Analog Supply Voltage
Digital Supply Voltage
SYMBOL
AV
DD
,
PV
DD
DV
DD
Full operation (Note 2),
no headphone or line
output load
Full operation (Note 2),
headphones disabled
Digital Supply Current
Analog Shutdown Current
Digital Shutdown Current
Shutdown to Full Operation
(Note 2)
Power-On to Full Operation
(Note 2)
0dBFS Output Voltage
Dynamic Range (Note 4)
DI
DD
AI
SHDN
DI
SHDN
t
ON
t
PON
Full operation (Note 2),
no line output load
AV
DD
= 1.8V
AV
DD
= 3.0V
AV
DD
= 1.8V
AV
DD
= 3.0V
DV
DD
= 1.8V
DV
DD
= 3.0V
AV
DD
= PV
DD
CONDITIONS
MIN
1.8
1.8
5.5
5.9
3.5
3.75
2.1
3.8
1.5
0.3
1.3
1.4
10
5
2.9
mA
µA
µA
ms
ms
5.3
TYP
MAX
3.6
3.6
7.7
mA
UNITS
V
V
Analog Supply Current
AI
DD
I
AVDD
+ I
PVDD
, A
VDD
= P
VDD
= 1.8V
Static digital interface, D
VDD
= 1.8V
DAC PERFORMANCE/LINE OUTPUTS
(Note 3)
V
OUT_FS
DR
AV
DD
= 3.0V
AV
DD
= 1.8V
Unweighted
Signal-to-Noise Ratio
(Note 5)
SNR
A-weighted
AV
DD
= 1.8V, unweighted
AV
DD
= 1.8V, A-weighted
82
1.85
1.95
87.5
87.5
88
91
88
91
dB
2.05
V
P-P
dB
2
_______________________________________________________________________________________
Stereo Audio DAC with DirectDrive
Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(DV
DD
= AV
DD
= PV
DD
= 3.0V, AGND = DGND = PGND = 0V, C1 = 0.47µF, C2 = 2.2µF, C
NREG
= C
PREG
= C
REF
= 1µF to AGND,
R
LOAD_HP
= 32Ω to AGND, R
LOAD_OUT
= 10kΩ to AGND, f
LRCLK
= 48kHz, f
MCLK
= 12.288MHz, volume set to -9.5dB, T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical specifications at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
0dBFS
-60dBFS
Total Harmonic Distortion Plus
Noise
THD+N
f
IN
= 984.375Hz
AV
DD
= 1.8V,
0dBFS
AV
DD
= 1.8V,
-60dBFS
Line Output Offset Voltage
Channel-to-Channel Gain
Matching
V
OS_LINE
ΔAV/AV
OUTL to OUTR, OUTR to OUTL
V
RIPPLE
= 100mV
P-P
, f
IN
= 1kHz, applied to
AV
DD
and PV
DD
V
RIPPLE
= 100mV
P-P
, f
IN
= 20kHz, applied
to AV
DD
and PV
DD
Crosstalk
Sampling Frequency Range
MCLK Frequency
DAC 8x INTERPOLATION FILTER
Passband Frequency
Frequency Response
Stopband Attenuation
Stopband Frequency
LINE INPUTS (INL, INR)
Line Input Voltage
IN_ to OUT_ Gain
Line Input Bias Voltage
INL and INR Input Resistance
PREG Output Voltage
NREG Output Voltage
REF Output Voltage
V
IN_LINE
A
V_LINE
V
BIAS_LINE
R
IN_LINE
V
PREG
V
NREG
V
REF
-1
-1.05
-15
10
-1
0
22
1.60
-1.15
1.23
+1
-0.95
+15
V
V/V
mV
kΩ
V
V
V
PB
FR
SBA
SB
Attenuation greater than SBA
To -1dB corner
10Hz to 20kHz
0
-0.1
58
0.58 x
f
S
7.42 x
f
S
0.48 x
f
S
+0.1
kHz
dB
dB
kHz
XTALK
f
S
f
MCLK
f
OUT
= 1kHz, V
OUT
= 2V
P-P
(OUTL to OUTR) or (OUTR to OUTL)
8
8.448
-15
MIN
TYP
87
27.5
-81
-27.5
0
±0.04
87
dB
67
-105
48
40
dB
kHz
MHz
-22
+15
mV
dB
dB
MAX
UNITS
MAX9850
Power-Supply Rejection Ratio
PSRR
INTERNAL REGULATORS (NREG, PREG)
_______________________________________________________________________________________
3
Stereo Audio DAC with DirectDrive
Headphone Amplifier
MAX9850
ELECTRICAL CHARACTERISTICS (continued)
(DV
DD
= AV
DD
= PV
DD
= 3.0V, AGND = DGND = PGND = 0V, C1 = 0.47µF, C2 = 2.2µF, C
NREG
= C
PREG
= C
REF
= 1µF to AGND,
R
LOAD_HP
= 32Ω to AGND, R
LOAD_OUT
= 10kΩ to AGND, f
LRCLK
= 48kHz, f
MCLK
= 12.288MHz, volume set to -9.5dB, T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical specifications at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
R
L
= 16Ω
AV
DD
= 3.0V
THD+N = 1%
f
IN
= 1kHz, headphone
volume = +6dB
R
L
= 32Ω
AV
DD
= 3.0V
R
L
= 16Ω
AV
DD
= 1.8V
R
L
= 32Ω
AV
DD
= 1.8V
Full-Scale Headphone Amplifier
Output Voltage
Line In to HP Output Voltage
Gain
Total Harmonic Distortion Plus
Noise
V
OUT_FS
A
V_HP
THD+N
Volume = +5dB, HP unloaded
Volume = +3dB, HP unloaded
R
L
= 32Ω, P
OUT
= 60mW, f
IN
= 1kHz
R
L
= 16Ω, P
OUT
= 60mW, f
IN
= 1kHz
Unweighted
Signal-to-Noise Ratio (Note 6)
SNR
A-weighted
AV
DD
= 1.8V, unweighted
AV
DD
= 1.8V, A-weighted
V
RIPPLE
= 100mV
P-P
, frequency = 1kHz,
applied to AV
DD
and PV
DD
V
RIPPLE
= 100mV
P-P
, frequency = 20kHz,
applied to AV
DD
and PV
DD
Headphone Output Offset
Voltage
Slew Rate
Maximum Capacitive Load
Crosstalk
Channel-to-Channel Gain
Matching
Internal Charge-Pump Oscillator
Frequency
Charge-Pump Operating
Frequency Range
Volume Control Range
V
OS_HP
SR
C
L
XTALK
ΔA
V
/A
V
f
CP
Charge-pump clock derived from MCLK
550
550
-73.5
No sustained oscillations
R
HP
= 32Ω, P
OUT
= 3.5mW, f
IN
= 1kHz
(HPL to HPR) or (HPR to HPL)
Volume = -11.5dB
T
A
= +25°C
T
A
= T
MIN
to T
MAX
-15
-25
0.47
150
-85
±0.05
667
775
775
+6.0
15
1.16
1.34
40
MIN
TYP
MAX
UNITS
HEADPHONE OUTPUTS (HPL, HPR)
95
65
mW
30
25
1.23
1.41
-94
-90
88
90
88
91
91
dB
72
+15
+25
mV
V/µs
pF
dB
dB
kHz
kHz
dB
dB
1.30
1.48
V
RMS
V/V
dB
Output Power
OUT
Power-Supply Rejection Ratio
PSRR
4
_______________________________________________________________________________________
Stereo Audio DAC with DirectDrive
Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(DV
DD
= AV
DD
= PV
DD
= 3.0V, AGND = DGND = PGND = 0V, C1 = 0.47µF, C2 = 2.2µF, C
NREG
= C
PREG
= C
REF
= 1µF to AGND,
R
LOAD_HP
= 32Ω to AGND, R
LOAD_OUT
= 10kΩ to AGND, f
LRCLK
= 48kHz, f
MCLK
= 12.288MHz, volume set to -9.5dB, T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical specifications at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Mute Attenuation
DIGITAL INPUTS (GPIO, SCL, SDA, BCLK, LRCLK, SDIN, ADD, MCLK)
Input High Voltage
Input Low Voltage
Input Leakage Current
Input Hysteresis
Input Capacitance
Output-High Leakage Current
Output Low Voltage
C
IN
I
OH
V
OL
V
OH
= DV
DD
(Note 7)
DV
DD
> 2V
I
OL
= 3mA
DV
DD
< 2V
V
IH
V
IL
I
IH
, I
IL
V
IH
= DV
DD
, V
IL
= DGND
-10
0.09 x
DV
DD
10
1
0.4
0.2 x
DV
DD
DV
DD
-
0.4
0.4
0.7 x
DV
DD
0.25 x
DV
DD
Full shutdown, V
IH
= DV
DD
Normal operation, V
IH
= DV
DD
Full shutdown, V
IL
= DGND
Normal operation, V
IL
= DGND
0.05 x
DV
DD
400
1
1
100
V
0.8 x
DV
DD
0.2 x
DV
DD
+10
V
V
µA
V
pF
µA
SYMBOL
CONDITIONS
MIN
TYP
100
MAX
UNITS
dB
MAX9850
OPEN-DRAIN DIGITAL OUTPUTS (GPIO, SDA)
CMOS DIGITAL OUTPUTS (BCLK, LRCLK)
Output High Voltage
Output Low Voltage
HEADPHONE SENSE INPUT (HPS)
Input High Voltage
Input Low Voltage
Input-High Leakage Current
Input-Low Leakage Current
Input Hysteresis
V
IH
V
IL
I
IH
I
IL
V
V
µA
µA
V
V
OH
V
OL
I
OH
= 1mA
I
OL
= 1mA
V
V
_______________________________________________________________________________________
5
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