lm4651 National Semiconductor Corporation, lm4651 Datasheet - Page 6

• Manufacturer Part Number: lm4651
• Description: Overture? Audio Power Amplifier 170w Class D Audio Power Amplifier Solution
• Manufacturer: National Semiconductor Corporation

www.national.com
LM4652 Pin Descriptions
Note: NC, no connect pins are floating pins. It is best to connect the pins to GND to minimize any noise from being coupled into
the pins.
External Components Description
Pin No.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
10
11
12
13
14
15
1.
2.
3.
4.
5.
6.
7.
8.
9.
1
2
3
4
5
6
7
8
9
Components
C
Symbol
C
R
B1
−V
+V
R
GND
R
TSD
VO
HG
HG
VO
C
LG
LG
START
R
C
R
C
B
R
NC
NC
NC
NC
NC
SCKT
R
R
C
D
R
C
L
OSC
DLY
byp
−C
BT
fI1
fI2
fI1
fI3
fI2
EE
CC
1
1
2
1
1
f
f
1
2
2
2
1
2
B4
A ground reference for the thermal shut down circuitry.
Low−Gate # 1 is the gate input to a bottom side MOSFET in the H-Bridge.
The negative voltage supply input for the power MOSFET H-Bridge.
The thermal shut down flag pin. This pin transitions to 6V when the die temperature
exceeds 150˚C.
No connection
Low−Gate # 2 is the gate input to a bottom side MOSFET in the H-Bridge.
The switching output pin for one side of the H-Bridge.
No connection.
No connection.
High−Gate # 2 is the gate input to a top side MOSFET in the H-Bridge.
No connection.
No connection.
The positive voltage supply input for the power MOSFET H-Bridge.
High−Gate # 1 is the gate input to a top side MOSFET in the H-Bridge.
The switching output pin for one side of the H-Bridge.
Works with R
R
See description above for R
Sets the gain and bandwidth of the system by creating a low pass filter for the Error
Amplifier’s feedback with C
See description above for R
Provides a reduction in the feedback with R
reduce effects on the pole created by R
System Gain.
R
note for R
See description above for R
Establish the second pole for the low pass filter in the feedback path at f
1/(2 R
See description above for R
Combined with C
= 1/[2 (L
Filters high frequency noise from the amplifier’s output to ground. Recommended value
is 0.1µF to 1µF.
See description for L
Bypass capacitors for V
Supply Bypassing and High Frequency PCB Design in the Application Information
section for more information.
Provides the bootstrap capacitance for the boot strap pin.
Sets the dead time or break before make to T
Controls the startup time with T
Sets the output short circuit current with I
Controls the switching frequency with f
Schottky diode to protect the output MOSFETs from fly back voltages.
fl2
fI2
)/ R
and C
fI3
fl2
C
) − (R
1
1
fI2
2C
fI1
, R
) (Hz).
creates a low pass filter with a pole at f
BYP
2
2
, R
2
for effect on System Gain.
/ R
)
fl1
BYP
1
⁄
2
1
] (Hz).
) + .5].
and R
1
(Refer to Figure 1)
creates a 2−pole, low pass output filter that has a −3dB pole at f
.
CC
fl2
, V
6
f
. 3dB pole is at f
1
f
fI2
fI3
.
to set the gain of the system. Gain = [(R
.
EE
.
.
, analog and digital voltages (V
START
Functional Description
= (8.5x10
Description
SW
fI2
SCKT
= 1 X 10
and C
fI2
C
. R
DLY
= 1/(2 R
= (1x10
4
fI1
fI1
) C
= (1.7x10
should be 10 X R
. See also note for R
9
START
C
/ (4000 + R
5
= 1/(2 R
f
)/ (10k \ R
C
f
) (Hz).
(seconds).
−12
DD
) (500 + R
fI2
OSC
, +6V, −6V). See
C
SCKT
fI1
fI2
) (Hz).
) (Hz). See also
2
/ R
minimum to
) (A).
1
, R
C
DLY
1
) x ((R
=
2
) (seconds).
for effect on
fl1
+
C