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AD1991
Class D/1-Bit Audio Power Output Stage
FUNCTIONAL BLOCK DIAGRAMS
2-Channel Mode
INA
INB
LEFT
INPUT
LEVEL SHIFTER
AND
SWITCH CONTROL
H-BRIDGE
AGND DGND
AV
DD
DV
DD
PV
DD
TEST
CONTROL
PGND
A1
A2
B1
B2
C1
C2
D1
D2
OUTA
3
OUTB
3
OUTC
3
OUTD
3
INC
IND
RIGHT
INPUT
CLK
RST/PDN
MUTE
CURRENT OVERLOAD
THERMAL SHUTDOWN
THERMAL WARNING
DATA LOSS
2 144
6
THERMAL PROTECTION
SHORT-CIRCUIT PROTECTION
MUTE CONTROL
H11548n
4-Channel Mode
INA
INB
LEVEL SHIFTER
AND
SWITCH CONTROL
H-BRIDGE
AGND DGND
AV
DD
DV
DD
PV
DD
TEST
CONTROL
PGND
A1
A2
B1
B2
C1
C2
D1
D2
INC
IND
CLK
RST/PDN
MUTE
CURRENT OVERLOAD
THERMAL SHUTDOWN
THERMAL WARNING
DATA LOSS
24 14
6
THERMAL PROTECTION
SHORT-CIRCUIT PROTECTION
MUTE CONTROL
H11548n
OUTA
3
LOAD
REQUIRING
DC VOLTAGE
SUPPLY
OUTD
3
LOAD
REQUIRING
DC VOLTAGE
SUPPLY
OUTB
3
OUTC
3
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 H11547 20 W @ 4 H9024 @ 14.4 V
2 H11547 20 W @ 8 H9024 @ 20 V
Mono Mode
1 H11547 40 W @ 4 H9024 @ 20 V
R
ON
< 320 mH9024 (per Transistor)
Efficiency > 85% @ Full Power/8 H9024
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
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).