Rainbow Electronics MAX9770 - Manual (Page 10)

MAX9770
1.2W Low-EMI, Filterless, Mono Class D Amplifier
with Stereo DirectDrive Headphone Amplifiers
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Detailed Description
The MAX9770 combines a mono 1.2W Class D speaker
amplifier and stereo 80mW DirectDrive headphone
amplifiers with integrated headphone sensing and
comprehensive click-and-pop suppression. A
mixer/multiplexer allows for selection and mixing
between two stereo input sources and a single mono
source. The MAX9770 features a high 80dB PSRR, low
0.015% THD+N, industry-leading click/pop perfor-
mance, and a low-power shutdown mode.
Class D Speaker Amplifier
The MAX9770 Class D amplifier features a true filter-
less, low EMI, switch-mode architecture that provides
Class AB-like performance with Class D efficiency.
Comparators monitor the MAX9770 input and compare
the input voltage to a sawtooth waveform. The com-
parators trip when the input magnitude of the sawtooth
exceeds the corresponding input voltage. The com-
parator resets at a fixed time after the rising edge of the
second comparator trip point, generating a minimum-
PIN
TQFN TSSOP
NAME FUNCTION
7 10 CPV DD Positive Charge-Pump Power Supply
8 11 CPV SS Charge-Pump Output. Connect to SV SS .
9 12 C1N Charge-Pump Flying Capacitor Negative Terminal
10 13 C1P Charge-Pump Flying Capacitor Positive Terminal
11 14 CPGND Charge-Pump Ground
12 15 SEL1
Select Stereo Channel 1 Inputs. Digital input. Drive SEL1 high to select inputs IN1_L and
IN1_R.
13 16 SEL2
Select Stereo Channel 2 Inputs. Digital input. Drive SEL2 high to select inputs IN2_L and
IN2_R.
14 17 SELM Select Mono Channel Input. Digital input. Drive SELM high to select the MONO input.
15 18 SHDN
Shutdown. Drive SHDN low to disable the device. Connect SHDN to V DD for normal
operation.
16 19 SYNC
Frequency Select and External Clock Input.
SYNC = GND: fixed-frequency PWM mode with f S = 1100kHz.
SYNC = Float: fixed-frequency PWM mode with f S = 1450kHz.
SYNC = V DD : spread-spectrum PWM mode with f S = 1220kHz ± 120kHz.
SYNC = Clocked: fixed-frequency PWM mode with f S = external clock frequency.
17 20 PGND Speaker Amplifier Power Ground
18 21 OUT+ Speaker Amplifier Positive Output
19 22 OUT- Speaker Amplifier Negative Output
20 23 PV DD Speaker Amplifier Power Supply
21 24 GAIN2 Gain Control Input 2
22 25 GAIN1 Gain Control Input 1
23 26 MONO Mono Channel Input
24 27 IN2_L Stereo Channel 2, Left Input
25 28 IN1_L Stereo Channel 1, Left Input
26 1 GND Ground
27 2 IN2_R Stereo Channel 2, Right Input
28 3 IN1_R Stereo Channel 1, Right Input
EP — EP Exposed Paddle. Can be left floating or tied to GND.
Pin Description (continued)