NTE7230 Integrated Circuit 2 x 8W Stereo BTL Audio Output Amplifier with DC Volume Control Description: The NTE7230 is a stereo BTL output amplifier with DC volume control in a 13−Lead Staggered SIP type package designed for use in TVs and monitors, but is also suitable for battery−fed portable recorders and radios. A missing current limiter (MCL) circuit is built−in. The MCL circuit is activated when the difference in current between the output terminal of each amplifier exceeds 100mA (typical 300mA). This level of 100mA allows for single−ended headphone applications. Features: D DC Volume Control D Mute Mode D Thermal Protection D Short−Circuit Proof D No Switch−On and Switch−Off Clicks D Good Overall Stability D Low Power Consumption D Low HF Radiation D ESD Protected on All Pins Absolute Maximum Ratings: Supply Voltage, VP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18V Input Voltage (Pin1, Pin3, Pin5, and Pin7), Vn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5V Repetitive Peak Output Current, IORM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.25A Non−Repetitive Peak Output Current, IOSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5A Total Power Dissipation (TC < +605C), Ptot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.25W Short−Circuit Time, tsc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Hour Virtual Junction Temperature, TVJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +1505C Operating Ambient Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −405 to +855C Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −555 to +1505C Thermal Resistance, Junction−to−Case, RthJC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4K/W Thermal Resistance, Junction−to−Ambient (In Free Air), RthJA . . . . . . . . . . . . . . . . . . . . . . . . 40K/W Power Dissipation: Assume VP = 12V and RL = 168. The maximum sine wave dissipation is 2 x 1.8W = 3.6W. At TA(max) = +605C: Rth tot = (150 − 60)/3.6 = 25K/W. Rth tot = RthJC + RthCHS = RthHS. RthCHS + RthHS = 25 − 4 = 21K/W. Electrical Characteristics: (VP = 12V, TA = +255C, fi = 1kHz, RL = 168 unless otherwise specified) Parameter Supply Voltage Total Quiescent Current Maximum Gain; V1.7 . 1.4V Output Power Total Harmonic Distortion Voltage Gain Input Signal Handling (RMS Value) Noise Output Voltage Bandwidth Supply Voltage Ripple Rejection DC Output Offset Voltage Input Impedance (Pin3 and Pin5) Channel Separation Channel Unbalance Symbol Test Conditions VP Iq(tot) PO THD GV Vi(RMS) Vo(n) B SVRR |VOS| Zi acs |Gv| VP = 12V, RL = 8, Note 1 THD = 10%, RL = 168 THD = 10%, RL = 88 THD = 10%, RL = 88, VP = 15V PO = 0.5W GV = 0dB, THD < 1% fi = 500kHz, Note 2 at −1dB Note 4 |V13 − V11| and |V10 − V8| RS = 5k8 Note 5 G1 = 0dB, Note 6 Mute Position; V1 = V7 = 0.4V +30mV Output Voltage in Mute Position VO(mute) Vi = 1.0V, Note 7 DC Volume Control Gain Control Range 5 GV Volume Control Current IDC V1 = V7 = 0V Min Typ Max Unit 4.5 − − 22 18.5 25 V mA 3.0 − − − 39.5 1 − − 34 − 15 40 − − 3.5 5.3 8 0.3 40.5 − 210 Note 3 38 0 20 − − − − − − 1.0 41.5 − − − − 200 25 − 1 1 W W W % dB V V dB dB mV k8 dB dB dB − 35 45 V 68 −20 73.5 −25 − −30 dB A Note 1. With a load connected to the outputs the quiescent current will increase, the maximum value of this increase being equal to the DC output offset voltage divided by RL. Note 2. The noise output voltage (RMS value) at fi = 500kHz is measured with RS = 08 and bandwidth = 5kHz. Note 3. 20Hz to 300kHz (typical). Note 4. The ripple rejection is measured with RS = 08 and f = 100Hz to 10kHz. The ripple voltage (Vripple = 200mV RMS) is applied to the positive supply rail. Note 5. The channel unbalance is measured with VDC1 = VDC2. Note 6. The channel unbalance at G1 = 0dB is measured with VDC1 = VDC2. Note 7. The noise output voltage (RMS value) is measured with RS = 5k8 unweighted. Functional Description: The NTE7230 is a stereo BTL output amplifier with two DC volume control stages. The device is designed for TVs and monitors, but is also suitable for battery−fed portable recorders and radios. In conventional DC volume control circuits, the control or input stage is AC−coupled to the output stage via external capacitors to keep the offset voltage low. In the NTE7230 the two DC volume control stages are integrated into the input stages so that no coupling capacitors are required and a low offset voltage is still maintained. The minimum supply voltage also remains low. The BTL principle offers th following advantages: D Lower peak value of the supply current D The frequency of the ripple on the supply voltage is twice the signal frequency Consequently, a reduced power supply voltage with smaller capacitors can be used which results in cost reductions. Functional Description (Cont’d): For portable applications there is a trend to decrease the supply voltage, resulting in a reduction of output power at conventional output stages. Using the BTL principle increases the output power. The maximum gain of the amplifier is fixed at 40.5dB. The DC volume control stages have a logarithmic control characteristic. Therefore, the total gain can be controlled from +40.5dB to −33dB. if the DC volume control voltage falls below 0.4V, the device will switch to the mute mode. The amplifier is short−circuit protected to GND, VP, and across the load. A thermal protection circuit is also implemented. If the crystal temperature rises above +1505C the gain will be reduced, thereby reducing the output power. Special attention is given to switch−on and switch−off clicks, low HF radiation, and a good overall stability. Pin Connection Diagram (Front View) 13 12 11 10 9 8 7 6 5 4 3 2 1 Output 1 (+) Power GND 1 Output 1 (−) Output 2 (−) Power GND 2 Output 2 (+) VC 2 Signal GND VI 2 VP VI 1 N.C. VC 1 .944 (24.0) Max .173 (4.4) .780 (19.8) .127 (3.25) 1 .472 (12.0) .640 (16.25) 13 .460 (11.7) .067 (1.7) .134 (3.4) .169 (4.3) .200 (5.08)