SGM8905 Datasheet, PDF (9/13 Pages) SG Micro Corp – Capless 2Vrms to 3Vrms Line Driver

SGM8905
Capless 2Vrms to 3Vrms Line Driver
with Adjustable Gain
APPLICATION INFORMATION (continued)
External Under-Voltage Detection
External under-voltage detection can be used to mute/shut down the SGM8905 before an input device can generate
a pop.
The threshold seen at the UVP pin is 1.13V. A hysteresis is introduced with a resistive divider, where thresholds for
startup and shutdown are determined respectively as follows:
Startup Threshold: V_UDPR = 1.13V × (R11 + R12) / R12
Shutdown Threshold: V_UDPF = 1.13V × (R11 + R12) / R12 - 4.8μA × (R13 + R11 || R12) × (R11 + R12) / R12
Hysteresis: 4.8μA × (R13 + R11 || R12) × (R11 + R12) / R12
The R13 is optional. If the R13 is not used, the UVP pin connects to the divider center tap directly.
VSUP_MO
R11
R13
R12
UVP pin 8
Capacitive Load
The SGM8905 has the ability to drive large capacitive load up to 220pF directly, and larger capacitive loads can be
accepted by adding a series resistor of 47Ω or larger.
Gain-Setting Resistors
The gain-setting resistors, R_IN and R_FB, must be placed close to the input pins to minimize the capacitive loading on
these pins and to ensure maximum stability of the SGM8905.
SG Micro Corp
www.sg-micro.com
MARCH 2017
9