ZXCD1210
High performance analog input Class D modulator
Description
The ZXCD1210 provides complete control and
modulation functions at the heart of high
efficiency high performance Class D switching
audio amplifier solutions. In combination with
high performance output stages and open or
closed loop architectures, the ZXCD1210
provides a high performance audio amplifier
with all the inherent benefits of Class D.
The ZXCD1210 solution uses proprietary
circuit design to realise the true benefits of
Class D without the traditional drawback of
poor distortion performance. The combination
of reference circuit designs, magnetic
component choice and layout are essential to
realising these benefits.
The ZXCD1210 reference designs provide output
powers up to 500W RMS with typical distortion
and noise of less than 0.05% and a dynamic
range of 98dB. The closed loop designs ensure a
high damping factor and excellent supply
rejection. The open loop designs provide high
performance
in
the
most
economic
implementation.
The closed loop reference designs include
circuits specifically for subwoofer applications
featuring a flat frequency response up to 250Hz.
The open loop designs give the ZXCD1210 the
ability to produce amplifiers with full a 20kHz
bandwidth.
Features
•
•
•
•
•
Output power 50W to 500W into 4
THD+N <0.05%
Dynamic range 98dB
Open loop and closed loop reference designs
Frequency response
Subwoofers: ±0.5dB from 10Hz to 250Hz
Full band: ±0.5dB from 20Hz to 20kHz
200kHz PWM frequency
Output drive free of crossover artifacts
QFN16 4x4 package
Applications
•
•
•
•
•
Subwoofers
Home theatre systems
Multimedia
Wireless speakers
Portable audio
•
•
•
0.3
0.28
0.26
0.24
0.22
0.2
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
100m
200m
500m
1
2
5
10
20
50
100
200
500
This plot shows the
THD+N versus power
plot for a 500W closed
loop subwoofer
reference design.
THD+N is 0.02%
between 10W and
200W which is
outstanding
performance.
THD+N (%)
Output power (W)
Issue 2 - October 2007
© Zetex Semiconductors plc 2007
1
www.zetex.com
ZXCD1210
Absolute maximum ratings
- Terminal voltage with respect to GND
V
CC
Power dissipation
Package thermal resistance ( ja)
Operating temperature range
Maximum junction temperature
Storage temperature range
20V
1W
55°C/W
-40°C to 70°C
125°C
-50°C to 85°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 conditions for extended periods
may affect device reliability.
Electrical characteristics
- Test conditions (unless otherwise stated) V
CC
= 16V, T
A
= 25°C
Symbol Parameter
Conditions
Min.
V
CC
I
SS
Operating voltage range
Quiescent current
(*)
Limits
Typ. Max.
16
18
45
50
150
200
250
±25
100
7.5
50
5.23
8.32
1.35
1.35
2.95
2.95
0.89
5.5
8.75
1.8
1.8
3.1
3.1
1.05
Units
12
V
mA
mA
kHz
%
mV
V
ns
V
CC
=12V
V
CC
= 18V, 16V
F
CK
T
CK
Clock frequency
Clock frequency tolerance
Clock capacitor =330pF
Clock capacitor = 330pF
V
OLPWM
Low level PWM output voltage No load
V
OHPWM
High level PWM output voltage No load
T
DR
PWM output rise and fall time
Load capacitance = 2200pF
1uF decoupling
1uF decoupling
T
REG5V5
REG5V5 tolerance
T
REG9V
R
AIN
R
SLI
B
AIN
B
SLI
V
CK
REF9V tolerance
Audio input impedance
Modulation input impedance
Audio input bias level
Modulation input bias level
Clock amplitude
5.77 V
9.18 V
2.3
2.3
k
k
3.25 V
3.25 V
1.2
V
NOTES:
(*) For optimum thermal performance it is recommended that the ZXCD1210 is operated with a V
CC
of 12V.
Issue 2 - October 2007
© Zetex Semiconductors plc 2007
2
www.zetex.com
ZXCD1210
Pin connection diagrams
16
1
2
3
4
5
6
7
8
15
14
13
12
11
10
9
QFN16 4x4 package
Pin no. Pin name
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
PWML
REG5V5
AINL
MODIL
MODOL
N/C
CK
MODOR
MODIR
AINR
Sgnd
PWMR
Pgnd
REG9VR
VCC
REG9VL
Pin description
PWM drive
Internal supply rail
Audio input
Modulation control
Modulation control
No connection
External capacitor to set PWM frequency
Modulation control
Modulation control
Audio input
Signal ground
PWM drive
Power ground
Internal supply rail
Internal supply pin
Internal supply rail
Issue 2 - October 2007
© Zetex Semiconductors plc 2007
3
www.zetex.com
ZXCD1210
Functional description
On chip series regulators drop the external V
CC
supply (12V recommended) to the 9V and 5.5V
supplies required by the internal circuitry of the device.
The on chip oscillator produces a clock which is set to approximately 200kHz by an external
capacitor and an on chip resistor. The clock is set at least an order higher in frequency than the
audio input. This clock is a triangle waveform which is used to modulate the incident analogue
signal in order to produce the required PWM output.
With no audio input signal applied, the PWM duty cycle is nominally 50%. As the audio input
signal ascends towards the peak level, the crossing points with the (higher frequency) triangle
wave also ascend. The PWM output exhibits a corresponding increase in output duty cycle.
Similarly, as the audio input signal descends, the duty cycle is correspondingly reduced. Thus the
triangle modulates the audio input generating a pulse width modulated (PWM) output. This
principle is illustrated below.
The PWM outputs drive the speaker load with the audio information contained in the PWM signal,
via the off chip gate drivers, H bridge and single stage LC filter network.
The triangle amplitude is approximately 1V. The audio inputs are internally biased to a DC voltage
of approximately V
CC
/5. The mid point DC level of the modulation control is around 2V. The
triangular wave at the CK pin traverses between about 2.7V and 3.8V.
PWM comparator
Audio
PWM output
Triangle
Audio
Triangle
Output
Comparator O/P (duty cycle = 50%)
Audio
Triangle
Output
Comparator O/P (duty cycle = 75%)
Audio input
Triangle input
PWM output
Issue 2 - October 2007
© Zetex Semiconductors plc 2007
4
www.zetex.com
ZXCD1210
Applications information
The high performance ZXCD1210 modulator IC forms the heart of the Zetex series of analog input
Class D amplifier reference designs. The modulator device provides complete control of the
modulation function.
Details of these reference designs are contained in individual data sheets: ZXCDSUBEV series,
ZXCD50STEVAL and ZXCD100MOEVAL as well as the ZXCD series design guide.
The ZXCDSUBEV series of reference circuits are specifically designed for subwoofer applications.
These switching amplifiers owe much of their outstanding audio performance to a unique
feedback architecture designed to reduce distortion. By taking its feedback signal from the filtered
amplifier output, the high gain circuit design compensates for bridge mismatches and filter non-
linearities, to achieve a reduction in THD+N across the entire power band.
Mute
Bridge
supply
Audio
input
Input
buffering
and bias
PWM
output
ZXCD1210
Gate
driver
Output
bridge
Filter
DC
Servo
AC comp
network
+
-
Feedback circuits
circuits
ZXCDSUBEV series architecture
0.3
0.28
THD+N (%)
0.26
0.24
0.22
0.2
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
100m
200m
500m
1
2
5
10
20
50
100
200
500
Output Power (W)
ZXCDSUBEV series THD+N versus power
Issue 2 - October 2007
© Zetex Semiconductors plc 2007
5
www.zetex.com
京公网安备 11010802033920号
EEWORLD
