max9746 Maxim Integrated Products, Inc., max9746 Datasheet - Page 10

• Manufacturer Part Number: max9746
• Description: Max9746 1.2w, Low-emi, Filterless, Class D Audio Amplifier
• Manufacturer: Maxim Integrated Products, Inc.

Figure 2. MAX9746 Output with an Input Signal Applied (SSM Mode)
The MAX9746 uses Maxim’s unique, patented modula-
tion scheme that eliminates the LC filter required by
traditional Class D amplifiers, improving efficiency,
reducing component count, and conserving board
space and system cost. Conventional Class D amplifiers
output a 50% duty-cycle square wave when no signal is
present. With no filter, the square wave appears across
the load as a DC voltage, resulting in finite load current,
increasing power consumption. When no signal is pre-
sent at the input of the MAX9746, the outputs switch as
shown in Figure 3. Because the MAX9746 drives the
speaker differentially, the two outputs cancel each other,
resulting in no net idle mode voltage across the speak-
er, minimizing power consumption.
1.2W, Low-EMI, Filterless,
Class D Audio Amplifier
10
Filterless Modulation/Common-Mode Idle
______________________________________________________________________________________
V
V
V
OUT+
IN+
IN-
- V
OUT-
OUT+
OUT-
t
ON(MIN)
t
SW
t
SW
Figure 3. MAX9746 Outputs with No Input Signal
V OUT+ - V OUT- = 0V
t
SW
V IN = 0V
OUT+
OUT-
t
SW