ETC EUA6210

芯美电子
EUA6210
Output Capacitor-less 67mW Stereo
Headphone Amplifier
DESCRIPTION
FEATURES
The EUA6210 is an audio power amplifier primarily
designed for headphone applications in portable device
applications. It is capable of delivering 67mW of
continuous average power per channel into a 16Ω load
with less than 1% distortion (THD+N) from a 3.3V power
supply.
The EUA6210 utilizes a new circuit topology that
eliminates output coupling capacitors and half-supply
bypass capacitors. It is ideally suited for low-power
portable applications where minimal space and power
consumption are primary requirements.
The EUA6210 is also unity-gain stable and can be
configured by external gain-setting resistors. Other features
include click/pop suppression, low-power shutdown mode
and thermal shutdown protection.
z
z
z
z
z
z
z
z
67mW per Channel into 16Ω from a 3.3V Supply at
THD=1% (Typ)
No Output Coupling Capacitors and Half-Supply
Bypass Capacitor Required
Integrated Click & Pop Suppression
Ultra-low <1µA Shutdown Current
Ultra-Gain Stable
2.7V-5.5V Operation
Available MSOP-8 Package
RoHS Compliant and 100% Lead(Pb)-Free
APPLICATIONS
z
z
z
z
Mobile Phones
PDAs
Portable Electronic Devices
Notebook Computers
Typical Application Circuit
Figure1.
DS6210 Ver1.1 Aug. 2007
1
联系电话:15999644579 83151715
芯美电子
EUA6210
Pin Configurations
Package Type
Pin Configurations
MSOP-8
Pin Description
PIN
PIN
I/O
IN1
1
I
IN2
2
I
SHUTDOWN
3
I
The device enters in shutdown mode when a low level is applied on this pin.
GND
4
-
Ground.
VDD
5
I
Analog VDD input supply.
VO3
6
O
Reference for speaker.
VO2
7
O
Channel 2 output.
VO1
8
O
Channel 1 output.
DS6210 Ver1.1 Aug. 2007
DESCRIPTION
Channel 1 input, connected to the feedback resistor Rf and to the input resistor
Rin.
Channel 2 input, connected to the feedback resistor Rf and to the input resistor
Rin.
2
联系电话:15999644579 83151715
芯美电子
EUA6210
Ordering Information
Order Number
Package Type
Marking
Operating Temperature range
EUA6210MIR1
MSOP-8
xxxxx
A6210
-40 °C to 85°C
EUA6210
□ □ □ □
Lead Free Code
1: Lead Free 0: Lead
Packing
R: Tape & Reel
Operating temperature range
I: Industry Standard
Package Type
M: MSOP
DS6210 Ver1.1 Aug. 2007
3
联系电话:15999644579 83151715
芯美电子
EUA6210
Absolute Maximum Ratings
▓
▓
▓
▓
▓
▓
▓
▓
Supply voltage, -----------------------------------------------------------------------------------------------6V
Input voltage ----------------------------------------------------------------------------------- -0.3 V to VDD +0.3V
Storage temperature --------------------------------------------------------------------------------- -65°C to 150°C
Power Dissipation ----------------------------------------------------------------------------------- Internally Limited
ESD Susceptibility Pin6 -------------------------------------------------------------------------------------8kV
ESD Susceptibility for other Pins --------------------------------------------------------------------------2kV
Junction Temperature --------------------------------------------------------------------------------------- 150°C
Thermal Resistance
θJC (MSOP) ----------------------------------------------------------------------------------------------- 56°C/W
θJA (MSOP) ----------------------------------------------------------------------------------------------- 160°C/W
Electrical Characteristics VDD = 3.3V
The following specifications apply for VDD=3.3V, AV=1, and 32Ω load unless otherwise specified. Limits apply to
TA=25℃.
Symbol
Parameter
Conditions
EUA6210
Typ
Min
Max.
(Note1)
Unit
IDD
Quiescent Power Supply Current
VIN=0V, 32Ω load
4.1
6
mA
ISD
Shutdown Current
VSHUTDOWN=GND
0.1
1.0
µA
VOS
Output Offset Voltage
4
30
mV
PO
THD=1%(max); f=1kHz,
32Ω load
THD=1%(max); f=1kHz,
16Ω load
Output Power
THD+N Total Harmonic Distortion + Noise
PSRR
Power Supply Rejection Ratio
VIH
Shutdown Input Voltage High
VIL
Shutdown Input Voltage Low
30
35
mW
67
PO=30mWrms; f=1kHz
Vripple=200mVp-p sinewave
Input Terminated with 10 ohms
to ground
0.2
%
59(f=217Hz)
48(f=1kHz)
dB
1.5
V
0.4
V
Note 1: Typicals are measured at 25˚C and represent the parametric norm.
Note 2: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 3: If the product is in shutdown mode and VDD exceeds 6V (to a max of 8V VDD) then most of the excess current will flow
through the ESD protection circuits.If the source impedance limits the current to a max of 10ma then the part will be protected. If the
part is enabled when VDD is above 6V circuit performance will be curtailed or the part may be permanently damaged.
DS6210 Ver1.1 Aug. 2007
4
联系电话:15999644579 83151715
芯美电子
EUA6210
Typical Operating Characteristics
Figure2. THD+N vs. Frequency
Figure3. THD+N vs. Frequency
Figure4. THD+N vs. Frequency
Figure5. THD+N vs. Output Power
Figure6. THD+N vs. Output Power
Figure7. THD+N vs. Output Power
DS6210 Ver1.1 Aug. 2007
5
联系电话:15999644579 83151715
芯美电子
EUA6210
Figure8. Output Power vs. Load Resistance
Figure9. Output Power vs. Load Resistance
Figure10. Channel Separation vs. Frequency
Figure11. Noise vs. Frequency
Figure12. Output Power vs. Supply Voltage
Figure13. Power Dissipation vs. Output Power
DS6210 Ver1.1 Aug. 2007
6
联系电话:15999644579 83151715
芯美电子
EUA6210
Figure14. Power Dissipation vs. Output Power
Figure15. Power Supply Rejection Ratio vs. Frequency
Figure16. Power Supply Rejection Ratio vs. Frequency
DS6210 Ver1.1 Aug. 2007
7
联系电话:15999644579 83151715
芯美电子
EUA6210
Amplifier Configuration Explanation
Application Information
As shown in Figure 1, the EUA6210 has three operational
amplifiers internally. Two of the amplifier’s have
externally configurable gain while the other amplifier is
internally fixed at the bias point acting as a unity-gain
buffer. The closed-loop gain of the two configurable
amplifiers is set by selecting the ratio of Rf to Ri.
Consequently, the gain for each channel of the IC is
Eliminating Output Coupling Capacitors
Typical single-supply audio amplifiers that drive singleended (SE) headphones use a coupling capacitor on each
SE output. This output coupling capacitor blocks the
half supply voltage to which the output amplifiers are
typically biased and couples the audio signal to the
headphones. The signal return to circuit ground is
through the headphone jack’s sleeve.
The EUA6210 eliminates these output coupling capacitors.
Amp3 is internally configured to apply a bandgap
referenced voltage (VREF = 1.58V) to a stereo headphone
jack’s sleeve. This voltage matches the quiescent voltage
present on the Amp1 and Amp2 outputs that drive the
headphones. The headphones operate in a manner similar
to a bridge-tied-load (BTL). The same DC voltage is
applied to both headphone speaker terminals. This results
in no net DC current flow through the speaker. AC current
flows through a headphone speaker as an audio signal’s
output amplitude increases on the speaker’s terminal.
The headphone jack’s sleeve is not connected to circuit
ground. Using the headphone output jack as a line-level
output will place the EUA6210’s bandgap referenced
voltage on a plug’s sleeve connection. This presents no
difficulty when the external equipment uses capacitively
coupled inputs. For the very small minority of equipment
that is DC coupled, the EUA6210 monitors the current
supplied by the amplifier that drives the headphone jack’s
sleeve. If this current exceeds 500mAPK, the amplifier is
shutdown, protecting the EUA6210 and the external
equipment.
Av = − ( R f / R i )
By driving the loads through outputs VO1 and VO2 with
VO3 acting as a buffered bias voltage the EUA6210 does
not require output coupling capacitors. The typical
single-ended amplifier configuration where one side of
the load is connected to ground requires large, expensive
output coupling capacitors.
A configuration such as the one used in the EUA6210 has
a major advantage over single supply, single-ended
amplifiers. Since the outputs VO1, VO2, and VO3 are all
biased at VREF= 1.58V, no net DC voltage exists across
each load. This eliminates the need for output coupling
capacitors that are required in a single-supply,
single-ended amplifier configuration. Without output
coupling capacitors in a typical single-supply,
single-ended amplifier, the bias voltage is placed across
the load resulting in both increased internal IC power
dissipation and possible loudspeaker damage.
Current Limit Protection Circuitry
In order to limit excessive power dissipation in the load
when a shout-circuit occurs, the current limit in the load
is fixed to 250mA. The current in the output MOS
transistors is real-time monitored, and when exceeding
250mA, the gate voltage of the corresponding MOS
transistor is clipped and no more current can be delivered.
Eliminating the Half-Supply Bypass Capacitor
Typical single-supply audio amplifiers are normally
biased to1/2VDD in order to maximize the output swing of
the audio signal. This is usually achieved with a simple
resistor divider network from VDD to ground that provides
the proper bias voltage to the amplifier. However, this
scheme requires the use of a half-supply bypass capacitor
to improve the bias voltage’s stability and the amplifier’s
PSRR performance.
Micro Power Shutdown
The voltage applied to the SHUTDOWN pin controls the
EUA6210’s shutdown function. Activate micro-power
shutdown by applying a logic-low voltage to the
SHUTDOWN pin. When active, the EUA6210’s
micro-power shutdown feature turns off the amplifier’s
bias circuitry, reducing the supply current. The trigger
point is 0.4V(max) for a logic-low level, and 1.5v(min)for
a logic-high level. The low0.1µA (typ) shutdown current
is achieved by applying a voltage that is as near as ground
as possible to the SHUTDOWN pin. A voltage that is
higher than ground may increase the shutdown current.
There are a few ways to control the micro-power
shutdown. These include using a single-pole, single-throw
switch, a microprocessor, or a microcontroller. When
using a switch, connect a external 100kΩ pull-up resistor
between the SHUTDOWN pin and VDD. Connect the
switch between the SHUTDOWN pin and ground. Select
normal amplifier operation by opening the switch. Closing
the switch connects the SHUTDOWN pin to ground,
activating micro-power shutdown. The switch and resistor
The EUA6210 utilizes an internally generated, buffered
bandgap reference voltage as the amplifier’s bias voltage.
This bandgap reference voltage is not a direct function of
VDD and therefore is less susceptible to noise or ripple on
the power supply line. This allows for the EUA6210 to
have a stable bias voltage and excellent PSRR
performance even without a half-supply bypass capacitor.
DS6210 Ver1.1 Aug. 2007
8
联系电话:15999644579 83151715
芯美电子
EUA6210
guarantee that the SHUTDOWN pin will not float. This
prevents unwanted state changes. In a system with a
microprocessor or microcontroller, use a digital output to
apply the control voltage the SHUTDOWN pin. Driving
the SHUTDOWN pin with active circuitry eliminates the
pull-up resistor.
In addition to system cost and size, turn-on time is
affected by the size of the input coupling capacitor Ci. A
larger input coupling capacitor requires more charge to
reach its quiescent DC voltage. This charge comes from
the output via the feedback Thus, by minimizing the
capacitor size based on necessary low frequency response,
turn-on time can be minimized. A small value of Ci (in the
range of 0.1µF to 0.39µF), is recommended.
Power Dissipation
Power dissipation is a major concern when designing a
successful amplifier. A direct consequence of the
increased power delivered to the load by a bridge
amplifier is an increase in internal power dissipation. The
maximum power dissipation for a given application can
be derived from the power dissipation graphs or from
Equation 1.
(
Power Supply Bypassing
As with any amplifier, proper supply bypassing is
important for low noise performance and high power
supply rejection. The capacitor location on the power
supply pins should be as close to the device as possible.
Typical applications employ a 3.3V regulator with 10µF
tantalum or electrolytic capacitor and a ceramic bypass
capacitor which aid in supply stability. This does not
eliminate the need for bypassing the supply nodes of the
EUA6210. A bypass capacitor value in the range of
0.1µF to 1µF is recommended for CS.
)
PDMAX = 4(VDD )2 / π 2 R L ----------------------------(1)
It is critical that the maximum junction temperature TJMAX
of 150℃ is not exceeded. Since the typical application is
for headphone operation (32Ω impedance ) using a 3.3V
supply the maximum power dissipation is only 138mW.
Therefore power dissipation is not a major concern.
Using External Powered Speakers
TheEUA6210 is designed specifically for headphone
operation. Often the headphone output of a device will be
used to drive external powered speakers. The EUA6210
has a differential output to eliminate the output coupling
capacitors. The result is a headphone jack sleeve that is
connected to VO3 instead of GND. For powered speakers
that are designed to have single-ended signals at the input,
the click and pop circuitry will not be able to eliminate the
turn- on/turn-off click and pop. Unless the inputs to the
powered speakers are fully differential the turn-on/
turn-off click and pop will be very large.
Gain-Setting Resistor Selection (Ri and Rf)
Ri and Rf set the closed-loop gain of the amplifier.
In order to optimize device and system performance, the
EUA6210 should be used in low gain configurations.
The low gain configuration minimizes THD + noise
values and maximizes the signal to noise ratio, and the
amplifier can still be used without running into the
bandwidth limitations. Low gain configurations require
large input signals to obtain a given output power. Input
signals equal to or greater than 1Vrms are available from
sources such as audio codecs.
A closed loop gain in the range from 2 to 5 is
recommended to optimize overall system performance.
An input resistor (Ri) value of 20kΩ is realistic in most of
applications, and does not require the use of a too large
capacitor Cin.
ESD Protection
As stated in the Absolute Maximum Ratings, pin 6(VO3)
on the EUA6210 has a maximum ESD susceptibility
rating of 8kV. For higher ESD voltages, the addition of a
PCDN042 dual transil (from California Micro Devices),
as shown in Figure 17, will provide additional protection.
Input Capacitor Selection (Ci)
Amplifiying the lowest audio frequencies requires a high
value input coupling capacitor, Ci. A high value capacitor
can be expensive and may compromise space efficiency in
portable designs. In many cases, however, the headphones
used in portable systems have little ability to reproduce
signals below 60Hz. Applications using headphones with
this limited frequency response reap little improvement by
using a high value input capacitor.
Figure 17.
DS6210 Ver1.1 Aug. 2007
9
联系电话:15999644579 83151715
芯美电子
EUA6210
Packaging Information
MSOP-8
SYMBOLS
A
A1
D
E1
E
L
b
e
DS6210 Ver1.1 Aug. 2007
MILLIMETERS
MIN.
MAX.
1.10
0.00
0.15
3.00
3.00
4.70
5.10
0.40
0.80
0.22
0.38
0.65
INCHES
MIN.
0.000
MAX.
0.043
0.006
0.118
0.118
0.185
0.016
0.008
0.201
0.031
0.015
0.026
10
联系电话:15999644579 83151715