Datasheet MAX4230, MAX4231, MAX4232, MAX4233, MAX4234 (Maxim) - 9

link to page 9 link to page 9 link to page 9 link to page 2 link to page 9 MAX4230–MAX4234 High-Output-Drive, 10MHz, 10V/μs, Rail-to-Rail I/O Op Amps with Shutdown in SC70 RF 3.6V CIN R LEFT IN C AUDIO INPUT OUT HEADPHONE JACK R TO 32Ω STEREO HEADSET C
MAX4230
VIN = 2VP-P
MAX4231
VBIAS
MAX4230
R COUT 32Ω CIN R RIGHT IN AUDIO INPUT RF Figure 1. MAX4230/MAX4231 Used in Single-Supply Operation Figure 2. Circuit Example: Adding a Coupling Capacitor Greatly Circuit Example Reduces Power Dissipation of its Package For example, the circuit in Figure 1 has a package power V dissipation of 196mW: PEAK R V MS ≅ 2 PEAK V RMS ≅ ( 1.0V DD V − DC V ) + = = 0.707V 2 RMS 2 1.0V = 3.6V −1.8V + = 2.507 I 1.0V / 32Ω R V MS PEAK I ≅ I + = 0A + 2 RMS DC 2 2 IPEAK 1.8V 1.0V / 32 I Ω = 22.1mA RMS ≅ IDC + = + RMS 2 32Ω 2 Therefore: = 78.4mARMS where: I P C(DISS) = RM V S IRMS COS θ VDC = the DC component of the output voltage. = 15.6mW IDC = the DC component of the output current. If the configuration in Figure 1 were used with all four of VPEAK = the highest positive excursion of the AC compo- the MAX4234 amplifiers, the absolute maximum power nent of the output voltage. dissipation rating of this package would be exceeded (see I the PEAK = the highest positive excursion of the AC compo- Absolute Maximum Ratings section). nent of the output current.
60mW Single-Supply Stereo
Therefore:
Headphone Driver
Two MAX4230/MAX4231s can be used as a single-supply, I P C(DISS) = RM V S IRMS COS θ stereo headphone driver. The circuit shown in Figure 2 can = 196mW deliver 60mW per channel with 1% distortion from a single 5V supply. Adding a coupling capacitor improves the package power The input capacitor (C dissipation because there is no DC current to the load, as IN), in conjunction with RIN, forms a highpass filter that removes the DC bias from the incom- shown in Figure 2: ing signal. The -3dB point of the highpass filter is given by 1 f 3 − dB = 2 R π INCIN www.maximintegrated.com Maxim Integrated │ 9