Class D/1-Bit Audio Power Output Stage
AD1991
FEATURES
Class D/1-Bit Audio Power Output Stage
5 V Analog and Digital Supply Voltages
Power Stage Power Supply 8 V to 20 V
Output Power @ 0.1% THD + N
Stereo Mode
2 20 W @ 4 @ 14.4 V
2 20 W @ 8 @ 20 V
Mono Mode
1 40 W @ 4 @ 20 V
R
ON
< 320 m (per Transistor)
Efficiency > 85% @ Full Power/8
Clickless Mute Function
Turn-On and Turn-Off Pop Suppression
Short-Circuit Protection
Overtemperature Protection
Data Loss Protection
2-Channel BTL Outputs or
4-Channel Single-Ended Outputs
52-Lead Exposed Pad TQFP Package
Low Cost DMOS Process
APPLICATIONS
PC Audio Systems
Minicomponents
Automotive Amplifiers
Home Theater Systems
Televisions
GENERAL DESCRIPTION
FUNCTIONAL BLOCK DIAGRAMS
2-Channel Mode
AV
DD
DV
DD
PV
DD
6
OUTA
INA
LEFT
INPUT
A1
A2
3
INB
B1
B2
LEVEL SHIFTER
AND
SWITCH CONTROL
H-BRIDGE
OUTB
3
OUTC
INC
RIGHT
INPUT
C1
C2
3
IND
D1
OUTD
D2
3
CURRENT OVERLOAD
THERMAL SHUTDOWN
THERMAL WARNING
DATA LOSS
14
PGND
CLK
RST/PDN
MUTE
n
THERMAL PROTECTION
SHORT-CIRCUIT PROTECTION
MUTE CONTROL
4
AGND DGND
2
TEST
CONTROL
4-Channel Mode
AV
DD
DV
DD
PV
DD
6
The AD1991 is a 2-channel BTL or 4-channel single-ended
class D audio power output stage. The part is configured during
reset to be in either 2-channel mode or 4-channel mode.
To protect the IC as well as the connected speakers, the AD1991
provides turn-on and turn-off pop suppression, short-circuit
protection, and overtemperature shutdown. To control the IC,
a power-down/reset input and a mute pin are available.
The output stage can be operated over a power supply range
from 8 V to 20 V.
In 2-channel mode, Transistors A1, B2, C1, and D2 are turned
on by a Logic 1 on inputs INA and INC, and Transistors A2,
B1, C2, and D1 are turned on by a Logic 0 on inputs INA and
INC. In 4-channel mode, Transistors A1, B1, C1, and D1 are
turned on by a Logic 1 on the four inputs, and Transistors A2,
B2, C2, and D2 are turned on by a Logic 0 on the four inputs
(see the Functional Block Diagrams).
INA
A1
A2
OUTA
3
LOAD
REQUIRING
DC VOLTAGE
SUPPLY
INB
B1
B2
LEVEL SHIFTER
AND
SWITCH CONTROL
H-BRIDGE
OUTB
3
INC
C1
C2
OUTC
3
IND
D1
D2
OUTD
3
LOAD
REQUIRING
DC VOLTAGE
SUPPLY
CLK
RST/PDN
MUTE
n
THERMAL PROTECTION
SHORT-CIRCUIT PROTECTION
MUTE CONTROL
CURRENT OVERLOAD
THERMAL SHUTDOWN
THERMAL WARNING
DATA LOSS
14
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
4
AGND DGND
2
TEST
CONTROL
PGND
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Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
漏 2003 Analog Devices, Inc. All rights reserved.
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