Datasheet

MAX9725
1V, Low-Power, DirectDrive, Stereo Headphone
Amplifier with Shutdown
_______________________________________________________________________________________ 7
PIN BUMP
THIN
QFN
UCSP
NAME FUNCTION
1 A1 C1N Flying Capacitor Negative Terminal. Connect a 1µF capacitor from C1P to C1N.
2A2PV
SS
Inverting Charge-Pump Output. Bypass with 1µF from PV
SS
to PGND. PV
SS
must be connected to
V
SS
.
3 A3 INL
Left-Amplifier Inverting Input. Connect input resistor R
IN
from input capacitor C1N to INL (MAX9725E
only).
4 A4 INR
Right-Amplifier Inverting Input. Connect input resistor R
IN
from input capacitor C1N to INR
(MAX9725E only).
5B4V
SS
Amplifier Negative Power Supply. Must be connected to PV
SS
.
6 B3 SGND
Signal Ground. SGND must be connected to PGND. SGND is the ground reference for the input and
output signal.
7 C4 OUTR Right-Channel Output. Connect feedback resistor R
FB
between OUTR and INR (MAX9725E only).
8 C3 OUTL Left-Channel Output. Connect feedback resistor R
FB
between OUTL and INL (MAX9725E only).
9C2V
DD
Positive Power-Supply Input. Bypass with a 1µF capacitor to PGND.
10 C1 C1P Flying Capacitor Positive Terminal. Connect a 1µF capacitor from C1P to C1N.
11 B1 PGND Power Ground. Ground reference for the internal charge pump. PGND must be connected to SGND.
12 B2 SHDN
Active-Low Shutdown. Connect to V
DD
for normal operation. Pull low to disable the amplifier and
charge pump.
EP — EP Exposed Paddle. Internally connected to V
SS
. Leave paddle unconnected or solder to V
SS
.
Pin Description
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
MAX9725 toc22
SUPPLY VOLTAGE (V)
SHUTDOWN CURRENT (μA)
1.31.1
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0
0.9 1.5
EXITING SHUTDOWN
MAX9725 toc23
200μs/div
OUT_
1V/div
SHDN
500mV/div
POWER-UP/-DOWN WAVEFORM
MAX9725toc24
200ms/div
OUT_
10mV/div
V
DD
1V/div
Typical Operating Characteristics (continued)
(V
DD
= 1.5V, V
PGND
= V
SGND
= 0V, V
SHDN
= 1.5V, V
SS
= V
PVSS,
C1 = C2 = 1µF, C
IN
= 1µF, THD+N measurement bandwidth = 22Hz
to 22kHz, T
A
= +25°C, unless otherwise noted.) (See the Functional Diagrams. )