The SGM4918 stereo headphone amplifier is designed for portable equipment where board space is at a premium. The SGM4918 uses capless architecture to produce a ground-referenced output from a single power supply, eliminating the need for large DC-blocking capacitors for output, saving cost, board space, and component height. Additionally, for SGM4918B, the gain is set internally (-2V/V), further reducing component count. For SGM4918A, the gain can be adjusted by external feedback resistors.
The SGM4918 delivers up to 80mW per channel into a 32Ω load and has low 0.03% THD+N. A -78dB power supply rejection ratio (PSRR) at 217Hz allows this device to operate from noisy digital supplies without an additional linear regulator. Comprehensive click-and-pop circuitry suppresses audible clicks and pops on startup and shutdown.
The SGM4918 operates from a single 2.7V to 5.1V supply, consumes only 5.8mA supply current, has short-circuit and thermal-overload protections, and is specified over the extended -40℃ to +85℃ temperature range. The SGM4918 is available in a Green TDFN-3×3-10L package.
SGM4918A: External Feedback Gain Network
SGM4918B: Fixed -2V/V Gain
No Bulky DC-Blocking Capacitors Required
Ground-Referenced Outputs Eliminate DC-Bias Voltage on Headphone Ground Pin
No Degradation of Low-Frequency Response Due to Output Capacitors
80mW into 32Ω Load from 5V Power Supply at THD+N = 0.1% (TYP, per Channel)
Low 0.03% THD+N
High PSRR (-78dB at 217Hz)
Integrated Click-and-Pop Suppression
2.7V to 5.1V Single Supply Operation
Low Quiescent Current (5.8mA at VDD = 5V)
Shutdown Control
Short-Circuit and Thermal-Overload Protections
Under-Voltage Lockout Function
-40℃ to +85℃ Operating Temperature Range
Available in a Green TDFN-3×3-10L Package
Notebook PCs
Cellular Phones
PDAs
MP3 Players
Smart Phones
Portable Audio Equipment
| Part Number | Status | Package | Pins | Pb-Free | Temp Range |
| SGM4918AYD10G/TR | Production | TDFN-3×3-10L | 10 | Y | -40℃ to +85℃ |
| SGM4918BYD10G/TR | Production | TDFN-3×3-10L | 10 | Y | -40℃ to +85℃ |
