2001 Microchip Technology Inc.
DS21483
TC4864
300mW Audio Power Amplifier with Shutdown Mode
TC4864-1 12/20/00
RM
ELECTRICAL CHARACTERISTICS: (Notes 1 and 2) (Continued)
Note 1:
All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 2:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which
the device is functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not guaranteed for parameters where no limit is given; however, the typical value is a good indication
of device performance.
Note 3:
The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX , θJA, and the ambient temperature TA.
.
The maximum allowable power dissipation is PDMAX = (TJMAX –TA)/θJA . For the TC4864, TJMAX = 150°C.The typical junction-to-ambient
thermal resistance, when board mounted, is 210
°C/W for the MSOP package.
Note 4:
Human body model, 100pF discharged through a 1.5 k
resistor.
Note 5:
Machine Model, 220pF –240pF discharged through all pins.
Note 6:
Typicals are measured at 25
°C and represent the parametric norm.
Note 7:
Limits are guaranteed to TelCom’s AOQL (Average Outgoing Quality Level).
Note 8:
The quiescent power supply current depends on the offset voltage when a practical load is connected to the amplifier.
Note 9:
The power dissipation limitation for the package occurs at 300mW of output power. This package limitation is based on 25
°C ambient
temperature and
θJA = 210°C/W. For higher output power possibilities refer to the Power Dissipation Section.
PIN DESCRIPTION
Pin No.
(MSOP)
Symbol
Description
1
SHDN
Shutdown Logic Input.
2VREF
Reference Voltage Output (VDD/2).
3IN
+
Non-Inverting Input.
4IN
–
Inverting Input.
5VO1
Non-Inverting Amplifier Output.
6VDD
Power Supply Input.
7
GND
Supply Power Return.
8VO2
Inverting Amplifier Output.
EXTERNAL COMPONENTS DESCRIPTION
Components
Functional Description
1
R
Inverting input resistance which sets the closed-loop gain in conjunction with RF. This resistor also
forms a high pass filter with C at fc = 1/(2πRC).
2
C
Input coupling capacitor which blocks the DC voltage at the amplifier's input terminals. Also creates a
highpass filter with R at fc = 1/(2πRC). Refer to the section Proper Selection of External
Components, for an explanation of how to determine the value of C.
3RF
Feedback resistance which sets the closed-loop gain in conjunction with R.
4CS
Supply bypass capacitor which provides power supply filtering. Refer to the Power Supply
Bypassing section for information concerning proper placement and selection of the supply bypass
capacitor.
5CB
Bypass pin capacitor which provides half-supply filtering. Refer to the Proper Selection of External
Components for information concerning proper placement and selection of CB.