Ordering number: 2137B

Thick Film Hybrid IC

STK4181V

AF Power Amplifier (Split Power Supply)

(45W + 45W min, THD = 0.08%)

Features Package Dimensions

• Pin-compatible with the STK4102II series. The unit: mm
STK4101V series use the same package and are avail- 4040
able for output 15W to 50W. [STK4181V]
• Built-in muting circuit to cut off various kinds of pop
noise
• Greatly reduced heat sink due to substrate temperature
125°C guaranteed
• Distortion 0.08% due to current mirror circuit
• Excellent cost performance

Specifications
Maximum Ratings at Ta = 25°C

Parameter Symbol Conditions Ratings Unit

Maximum supply voltage VCC max ±51 V
Thermal resistance θj-c 1.8 °C/W
Junction temperature Tj 150 °C
Operating substrate temperature Tc 125 °C
Storage temperature Tstg −30 to +125 °C
Available time for load short-circuit ts *1 VCC = ±34V, RL = 8Ω, f = 50Hz, Po = 45W 2 s

Recommended Operating Conditions at Ta = 25°C

Parameter Symbol Conditions Ratings Unit

Recommended supply voltage VCC ±34 V
Load resistance RL 8 Ω

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 STK4181V

Operating Characteristics at Ta = 25°C, VCC = ±34V, RL = 8Ω, VG = 40dB, Rg = 600Ω,

RL : non-inductive load

Parameter Symbol Conditions min typ max Unit

Quiescent current ICCO VCC = ±40.5V 20 40 100 mA
THD = 0.08%,
PO (1) 45 W
f = 20Hz to 20kHz
Output power
VCC = ±30V, THD = 0.2%,
PO (2) 50 W
RL = 4Ω, f = 1kHz
Total harmonic distortion THD PO = 1.0W, f = 1kHz 0.08 %
+0
Frequency response fL, fH PO = 1.0W, dB 20 to 50k Hz
–3
Input impedance ri PO = 1.0W, f = 1kHz 55 kΩ
Output noise voltage VNO *2 VCC = ±40.5V, Rg = 10kΩ 1.2 mVrms
Neutral voltage VN VCC = ±40.5V -70 0 +70 mV
Muting voltage VM -2 -5 -10 V

Notes. For power supply at the time of test, use a constant-voltage power supply
unless otherwise specified.
*1 For measurement of the available time for load short-circuit and output
noise voltage, use the specified transformer power supply shown right.
*2 The output noise voltage is represented by the peak value on rms scale
(VTVM) of average value indicating type. For AC power supply, use an
AC stabilized power supply (50Hz) to eliminate the effect of flicker noise
in AC primary line.
Specified Transformer Power Supply
(Equivalent to MG-200)

Equivalent Circuit

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 STK4181V

Sample Application Circuit

Sample Printed Circuit Pattern for Application Circuit (Cu-foiled side)

Total harmonic distortion, THD - %
Output power, PO - W

Input voltage, Vi - mV Output power, PO - W

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 Voltage gain, VG - dB Output power, PO - W Total harmonic distortion, THD - %

Frequency, f - Hz
Output power, PO - W

Supply voltage, VCC - V

Quiescent current, ICCO - mA Voltage gain, VG - dB Output power, PO - W
STK4181V

Frequency, f - Hz

Frequency, f - Hz

Operating substrate temperature, Tc - °C

No. 2137—4/8
Neutral voltage, VN - mV
 STK4181V

IC Power dissipation, Pd - W
Quiescent current, ICCO - mA

Supply voltage, VCC - V Neutral voltage, VN - mV Output power, PO - W

IC Power dissipation, Pd - W

Output power, PO - W

Description of External Parts

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 STK4181V

Input filter capacitors

C3, C4
• A filter formed with R5 or R6 can be used to reduce noise at high frequencies.
Input coupling capacitors
• Used to block DC current. When the reactance of the capacitor increases at low frequencies, the dependence of 1/f noise on signal source
C5, C6 resistance causes the output noise to worsen. It is better to decrease the reactance.
• To reduce the pop noise at the time of application of power, it is effective to increase C5, C6 that fix the time constant on the input side and
to decrease C9, C10 on the NF side.
NF capacitors
• These capacitors fix the low cutoff frequency as shown below.
1
C9, C10 f L = --------------------------
- [Hz]
2π ⋅ C9 ⋅ R7
To provide the desired voltage gain at low frequencies, it is better to increase C9. However, do not increase C9 more than needed because
the pop noise level becomes higher at the time of application of power.
Decoupling capacitor
C19
• Used to eliminate the ripple components that mix into the input side from the power line (+VCC).
Bootstrap capacitors
C15, C16
• When the capacitor value is decreased, the distortion is liable to be higher at low frequencies.
Oscillation blocking capacitors
C17, C18 • Must be inserted as close to the IC power supply pins as possible so that the power supply impedance is decreased to operate the IC stably.
• Electrolytic capacitors are recommended for C17, C18.
Capacitor for ripple filter
C20
• Capacitor for the TR12-used ripple filter in the IC system
Oscillation blocking capacitor
C13
• A polyester film capacitor, being excellent in temperature characteristic, frequency characteristic, is recommended for C13.
R5, R6 Resistors for input filter
Input bias resistors
R3, R4
• Used to bias the input pin potential to zero. These resistors fix the input impedance practically.
These resistors fix voltage gain VG.
R7, R9 It is recommended to use R7 (R8) = 560Ω, R9 (R10) = 56kΩ for VG = 40dB.
(R8, R10) • To adjust VG, it is desirable to change R7 (or R8).
• When R7 (or R8) is changed to adjust VG, R3 (=R4) =R9 (=R10) must be set to ensure VN balance.
R11, R20 Bootstrap resistors
(R12, R21) • The quiescent current is set by these resistors 3.3kΩ + 3.3kΩ. It is recommended to use this resistor value.
Resistor for ripple filter
R15
• (Limiting resistor for predriver TR at the time of load short)
R14 Used to ensure plus/minus balance at the time of clip.
Resistor for ripple filter
R18, R19 • When muting TR13 is turned ON, current flows from ground to -VCC through TR 13. It is recommended to use 1kΩ (1W) + 1kΩ (1W)
allowing for the power that may be dissipated on that occasion.
R24, R25 Oscillation blocking resistors
R22, R23 Oscillation blocking resistors
L1, L2 Oscillation blocking coils

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 STK4181V

Sample Application Circuit (protection circuit and muting circuit)

Thermal Design
The IC power dissipation of the STK4181V at the IC-operated mode is 66W max. at load resistance 8Ω and 99W max. at
load resistance 4Ω (simultaneous drive of 2 channels) for continuous sine wave as shown in Figure 1 and 2.
IC Power dissipation, Pd - W

IC Power dissipation, Pd - W

Output power, PO - W Output power, PO - W

Figure 1. STK4181V Pd – PO (RL = 8Ω) Figure 2. STK4181V Pd – PO (RL = 4Ω)

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 STK4181V

In an actual application where a music signal is used, it is impractical to estimate the power dissipation based on the con-
tinuous signal as shown above, because too large a heat sink must be used. It is reasonable to estimate the power dissipa-
tion as 1/10 Po max. (EIAJ).
That is, Pd = 40W at 8Ω, Pd = 55W at 4Ω
Thermal resistance θc-a of a heat sink for this IC power dissipation (Pd) is fixed under conditions 1 and 2 shown below.
Condition 1: Tc = Pd × θc-a + Ta ≤ 125°C .............................................. (1)
where Ta : Specified ambient temperature
Tc : Operating substrate temperature
Condition 2: Tj= Pd × (θc-a) + Pd/4 × (θj-c) + Ta ≤ 150°C..................... (2)
where Tj : Junction temperature of power transistor
Assuming that the power dissipation is shared equally among the four power transistors (2 channels × 2), thermal resis-
tance θj-c is 1.8°C/W and
Pd × (θc-a + 1.8/4) + Ta ≤ 150°C........................................ (3)
Thermal resistance θc-a of a heat sink must satisfy ine-
qualities (1) and (3).
Figure 3 shows the relation between Pd and θc-a given
from (1) and (3) with Ta as a parameter. Thermal resistance of heat sink, θc-a - °C/W

[Example] The thermal resistance of a heat sink is

obtained when the ambient temperature speci-
fied for a stereo amplifier is 50°C.
Assuming VCC = ±34V, RL = 8Ω,
VCC = ±30V, RL = 4Ω,
RL = 8Ω : Pd1 = 40W at 1/10 Po max.
RL = 4Ω : Pd2 = 55W at 1/10 Po max.
The thermal resistance of a heat sink is
obtained from Figure 3.
RL = 8Ω : θc-a1 = 1.87°C/W IC Power dissipation, Pd - W
RL = 4Ω : θc-a2 = 1.37°C/W
Figure 3. STK4181V θc-a – Pd
Tj when a heat sink is used is obtained from
(3).
RL = 8Ω : Tj = 142.8°C
RL = 4Ω : Tj = 150°C

■ No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear
power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury,
death or property loss.
■ Anyone purchasing any products described or contained herein for an above-mentioned use shall:
➀ Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their
officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated
with such use:
➁ Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO.,
LTD., its affiliates, subsidiaries and distributors or any of their officers and employees, jointly or severally.
■ Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO
believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of
intellectual property rights or other rights of third parties.

This catalog provides information as of July, 1997. Specifications and information herein are subject to change without notice.
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