Rainbow Electronics MAX9820 - Manual (Page 8)

MAX9820
Detailed Description
The MAX9820 95mW stereo headphone amplifier fea-
tures Maxim’s patented DirectDrive architecture, elimi-
nating the large output-coupling capacitors required by
conventional single-supply headphone amplifiers. The
device features low RF susceptibility, extensive click-
and-pop suppression, undervoltage lockout (UVLO)
and shutdown control. The MAX9820 also features ther-
mal-overload and short-circuit protection.
The MAX9820 is Windows Vista Premium Mobile com-
pliant (Table 1).
DirectDrive
Conventional single-supply headphone amplifiers have
their outputs biased about a nominal DC voltage (typi-
cally half the supply) for maximum dynamic range.
Large-coupling capacitors are needed to block this DC
bias from the headphone. Without these capacitors, a
significant amount of DC current flows to the head-
phone, resulting in unnecessary power dissipation and
possible damage to both headphone and headphone
amplifier.
Maxim’s patented DirectDrive architecture uses a
charge pump to create an internal negative supply volt-
age, allowing the MAX9820 outputs to be biased at
DirectDrive Headphone Amplifier
with External Gain
8 _______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 C1P Flying Capacitor Positive Terminal. Connect a 1µF ceramic capacitor from C1P to C1N.
2 C1N Flying Capacitor Negative Terminal. Connect a 1µF ceramic capacitor from C1N to C1P.
3 V SS Charge-Pump Output. Bypass with a 1µF capacitor to GND.
4 OUTL Left-Channel Output
5 OUTR Right-Channel Output
6 INR Right-Channel Input
7 INL Left-Channel Input
8 V DD Positive Power-Supply Input. Bypass with a 10µF capacitor to GND.
9 SHDN Active-Low Shutdown Input
10 GND Signal Ground
— EP
Exposed Pad. Internally connected to GND. Connect to a large ground plane to maximize thermal
performance. Not intended as an electrical connection point.
DEVICE TYPE REQUIREMENT
WINDOWS VISTA PREMIUM MOBILE
SPECIFICATIONS
MAX9820
TYPICAL PERFORMANCE
THD+N ≤ -65dB FS (100Hz, 20kHz) -83dBFS (100Hz, 20kHz)
Dynamic range with signal
present
≤ -80dBV, A-weighted (20Hz, 20kHz)
-101dB A-weighted
(20Hz, 20kHz)
Analog Line Output
Jack (R
L = 10k Ω,
FS = 0.707V RMS )
Line output crosstalk ≤ -50dB (20Hz, 15kHz) -73dB (20Hz, 15kHz)
THD+N ≤ -45dB FS (100Hz, 20kHz) -85dBFS (100Hz, 20kHz)
Dynamic range with signal
present
≤ -60dBV, A-weighted (20Hz, 20kHz)
-94dB A-weighted
(20Hz, 20kHz)
Analog Headphone
Out Jack (R
L = 32 Ω,
FS = 0.300V RMS )
Headphone output crosstalk ≤ -50dB (20Hz, 15kHz) -73dB (20Hz, 15kHz)
Table 1. Windows Vista Premium Mobile Specifications vs. MAX9820 Specifications
Note: THD+N, dynamic range, and crosstalk are measured in accordance with AES-17 audio measurements standards.