MAXIM DS4420 User Manual
General Description
The DS4420 is a fully differential, programmable-gain
amplifier for audio applications. It features a -35dB to
+25dB gain range controlled by an I
2
C interface and it
is optimized to drive loads as low as 50Ω. The gain is
adjustable in 3dB increments across the entire range.
Three address inputs, used to select the I
2
C slave
address, enable up to eight devices on a common bus.
The product operates from a single 5V supply over a
-20°C to +70°C temperature range. It is offered in a
3mm x 3mm TDFN package.
Applications
Telephone Headsets
Audio Volume Control
Microphone Gain Control
Features
Differential Inputs and Outputs
-35dB to +25dB Adjustable Gain
Low Output Noise
Low-Distortion Driving into a 50Ω Load
3dB Gain Steps Programmed through I
2
C Interface
5V Single Supply
20kHz Bandwidth for All Gain Settings
Small 3mm x 3mm x 0.8mm TDFN Package
Up to Eight DS4420s can be Placed on the Same
I
2
C Bus
DS4420
I2C Programmable-Gain Amplifier
for Audio Applications
______________________________________________
Maxim Integrated Products
1
Rev 0; 9/06
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.
Ordering Information
+
Denotes lead-free package.
*
EP = Exposed paddle.
DS4420
-35dB
TO +25dB
GAIN
A2
A1
A0
SDA
SCL
IN+
OUT+
OUT-
IN-
GND
V
CC
AGND
AV
CC
AUDIO
AMPLIFIER
AUDIO
SOURCE
MICROPR0CESSOR-
CONTROLLED GAIN
I
2
C INTERFACE
Typical Operating Circuit
TDFN
(3mm x 3mm x 0.8mm)
TOP VIEW
2
4
5
13
11
10
OUT+
AGND
N.C.
A1
SCL
SDA
1
+
14
AV
CC
OUT-
A2
3
12
A0
6
9
IN-V
CC
7
8
IN+GND
DS4420
Pin Configuration
PART TEMP RANGE PIN-PACKAGE
DS4420+ -20°C to +70°C 14 TDFN-EP*
DS4420
I2C Programmable-Gain Amplifier
for Audio Applications
2 _____________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
RECOMMENDED OPERATING CONDITIONS
(TA= -20°C to +70°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.
Voltage on VCC, SDA, and SCL
Relative to GND.................................................-0.5V to +6.0V
Voltage on A0, A1, and A2
Relative to GND......................................-0.5V to (V
CC
+ 0.5V;
not to exceed 6.0V)
Voltage on IN+, IN-, OUT-, and OUT+
Relative to AGND .................................-0.5V to (AV
CC
+ 0.5V;
not to exceed 6.0V)
Voltage on AV
CC
Relative to VCC..........................-0.3V to +0.3V
Voltage on AGND Relative to GND .......................-0.3V to +0.3V
Output Current ..................................................................150mA
Operating Temperature Range ...........................-20°C to +70°C
Storage Temperature .....................See J-STD-020 Specification
ELECTRICAL CHARACTERISTICS
(V
CC
= +4.5V to +5.5V, TA = -20°C to +70°C, unless otherwise noted.)
Digital Supply Voltage V
Analog Supply Voltage AV
Analog Ground AGND (See Figure 5) GND V
Input Logic 1 (SCL, SDA, A0, A1, A2) V
Input Logic 0 (SCL, SDA, A0, A1, A2) V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
(Note 1) +4.5 +5.5 V
CC
CC
IH
IL
2.0
-0.3 +0.8 V
V
CC
V
CC
+ 0.3
Supply Current I
Standby Current I
Input Leakage (SDA, SCL, A2, A1, A0) I
Output Leakage (SDA) I
Output-Current Low (SDA) I
Input Voltage Range V
Max Peak-to-Peak Input Level V
Input Resistance R
Input Common-Mode Voltage V
Output Voltage V
Output Peak-to-Peak Signal Swing V
Output Common-Mode Voltage V
Output Offset Voltage V
Amplifier Output Current
(Sourcing)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CC
STBY
IL
L
OL
IN
INP-P
IN
IN:CM
O
OP-P
O:CM
O:OSAV
I
OS1
VCC = 5.5V, RL = ∞, VIN = 0V differential
(Note 9)
VCC = 5.5V (Notes 2, 9) 140 µA
VCC = 5.5V 1 µA
VOL = 0.4V 3
VOL = 0.6V 6
Differential -19 +1 dBV
Differential 3.2 V
Differential, active mode (Note 3) 29 49 60 kΩ
0.45 x
V
CC
RL = 50Ω differential 6 dBV
Differential 5.6 V
0.45 x
V
CC
= +25dB -20 +20 mV
= GND 95
V
OUT
V
= VCC - 0.75V 64
OUT
1.7 3 mA
1µA
0.55 x
V
CC
0.5 x
V
CC
0.55 x
V
CC
V
V
mA
V
V
mA
DS4420
I2C Programmable-Gain Amplifier
for Audio Applications
_____________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +4.5V to +5.5V, TA = -20°C to +70°C, unless otherwise noted.)
I2C AC ELECTRICAL CHARACTERISTICS (See Figure 3)
(VCC= +4.5V to +5.5V, TA= -20°C to +70°C, timing referenced to V
IL(MAX)
and V
IH(MIN)
, unless otherwise noted.)
Amplifier Output Current
(Sinking)
Resistive Load Range R
Capacitive Load C
Closed-Loop Bandwidth All gain settings (Note 5) 20 20k Hz
Passband Flatness 20Hz to 20kHz (Notes 2, 5) -1 +1 dB
Output Noise (Note 5) N
Total Harmonic Distortion (Note 5) THD
Gain Range A -35 +25 dB
Gain Step Size A
Gain Accuracy A
Mute and Standby Mode Gain A
S tand b y M od e E xi t Ti m et
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
I
OS2
L
L
O
S
ERR1
MUTE
PU
= V
OUT
V
OUT
Differential 50 50k Ω
Cap to GND (Note 4) 100 pF
A = -35dB, 300Hz to 3.4kHz -123
A = +25dB, 300Hz to 3.4kHz -88
RL = 50Ω, VO ≤ +6dBV,
f = 1kHz, A = ±16dB
R
L
f = 1kHz, A = ±16dB
(Note 10) -2.5 +2.5 dB
(Note 5) -90 dB
(Note 6) 10 µs
CC
= 0.75V 64
= 1kΩ, V
≤ +6dBV,
O
89
0.03 1.0
0.01
2.0 3.0 4.0 dB
mA
dBV
%
SCL Clock Frequency f
Bus Free Time Between STOP and
START Conditions
Hold Time (Repeated) START
Condition
Low Period of SCL t
High Period of SCL t
Data Hold Time t
Data Setup Time t
Start Setup Time t
SDA and SCL Rise Time t
SDA and SCL Fall Time t
STOP Setup Time t
SDA and SCL Capacitive Loading C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SCL
t
BUF
t
HD:STA
LOW
HIGH
HD:DAT
SU:DAT
SU:STA
SU:STO
(Note 7) 0 400 kHz
(Note 8)
R
(Note 8)
F
(Note 8) 400 pF
B
1.3 µs
0.6 µs
1.3 µs
0.6 µs
0 0.9 µs
100 ns
0.6 µs
20 +
0.1C
B
20 +
0.1C
B
0.6 µs
300 ns
300 ns
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