Page 1
Ordering number: EN2885A
°
−
°
8 Ω
Thick Film Hybrid IC
STK4432
AF Power Amplifier
(25W + 25W min, THD = 1.0%)
Features
• Small and slim package with 31 mm height
• Pin compatible with STK430 series heretofore in use
• Greatly reduced heat sink due to case temperature
Package Dimensions
unit: mm
4033
[STK4432]
125 ° C guaranteed
• Excellent cost performance
Specifications
Maximum Ratings
Parameter Symbol Conditions Ratings Unit
Maximum supply voltage
Operating substrate temperature Tc 125
Storage temperature Tstg
Available time for load short-circuit t
at Ta = 25 ° C
V
max 70 V
CC
30 to +125
V
= 49V, R
s
CC
= 8 Ω , f = 50Hz, Po = 25W 2 s
L
C
C
Recommended Operating Conditions
Parameter Symbol Conditions Ratings Unit
Recommended operating voltage V
Load resistance R
Operating Characteristics
Parameter Symbol Conditions min typ max Unit
Quiescent current Icco V
Output power
Total harmonic distortion THD Po = 0.1W, f = 1kHz 0.3 %
Frequency response f
Input impedance r
Output noise voltage V
at Ta = 25 ° C, V
Po (1) THD = 1.0%, f = 1kHz 25 W
Po (2)
, f
L
H
i
NO
at Ta = 25 ° C
CC
L
= 49V, R
CC
= 58V 20 60 120 mA
CC
THD = 1.0%,
f = 30Hz to 20kHz
Po = 0.1W, dB 20 to 100k Hz
Po = 0.1W, f = 1kHz 110 k Ω
V
= 58V, Rg = 10k Ω
CC
= 8 Ω , Rg = 600 Ω , VG = 40dB
L
13 W
+0
−3
49 V
0.8 mVrms
SANYO Electric Co., Ltd. Semiconductor Business Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
110297HA (ID) / 9088TA, TS No. 2885—1/7
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STK4432
Notes. For power supply at the time of test, use a constant-voltage power
supply unless otherwise specified.
For measurement of the available time for load short-circuit and output noise voltage, use the specified transformer power supply shown
right.
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.
Equivalent Circuit
Specified Transformer Power Supply
(Equivalent to RP-25)
Sample Application Circuit:
25W min 2-Channel AF Power Amplifier
No. 2885—2/7
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STK4432
Sample Printed Circuit Pattern for Application Circuit
(Cu-foiled side)
Output power, Po - WOutput power, Po - W
Total harmonic distortion, THD - %Voltage gain, VG - dB
Input voltage, Vi - mV
Frequency, f - Hz
Output power, Po - W
Frequency, f - Hz
No. 2885—3/7
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STK4432
Quiescent current, Icco - mACurrent drain, I
- A
CC
Operating substrate temperature, Tc - ° C
Supply voltage, V
CC
- V
Quiescent current, Icco - mAIC Power dissipation, Pd - W
Supply voltage, V
CC
- V
Output power, Po - W
Output power, Po - W
Voltage gain, VG - dB
Frequency, f - Hz
No. 2885—4/7
Page 5
Description of External Parts
Ω
STK4432
C1, C2
C3, C4
C5, C6
C15
R7, R8 Front stage bias resistors
R11 Front stage bias resistor
C9, C10
R1, R2 Resistors for input filter
R12 Front stage bias resistor
R3, R5
(R4, R6)
C7, C8
R13
C11, C12
C13
C14
R9, R10 Oscillation blocking resistors
Input filter capacitors
• A filter formed with R1 or R2 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
resistance causes the output noise to worsen. It is better to decrease the reactance.
NF capacitors
• These capacitors fix the low cutoff frequency shown below.
f
---------------------------------- -
=
L
π
C5 R3
⋅⋅
2
To provide the desired voltage gain at low frequencies, it is better to increase C5. However, do not increase C5 more than needed because
the pop noise level becomes higher at the time of application of power.
Capacitor for ripple filter
• Used to eliminate the ripple components that mix into the input side from the power line (+V
Oscillation blocking capacitors
• A polyester film capacitor, being excellent in temperature characteristic, frequency characteristic, is recommended for C9, C10.
These resistors fix voltage gain VG.
It is recommended to use R3 (R4) = 12
• To adjust VG, it is desirable to change R3 (or R4).
Bootstrap capacitors
• When the capacitor value is decreased, the distortion is liable to be higher at low frequencies.
Resistor for ripple filter
(Limiting resistor for predriver TR at the time of load short)
Output capacitors
• These capacitors fix the low cutoff frequency.
Oscillation blocking capacitor
• 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.
Decoupling capacitor
• When the capacitor value is increased, the starting time is made longer.
1
Hz
).
CC
for VG = 40dB.
No. 2885—5/7
Page 6
STK4432
Sample Application Circuit
(protection circuit and muting circuit)
Thermal Design
The IC power dissipation of the STK4432 at the IC-operated mode is 30W max. at load resistance 8 Ω (simultaneous drive of 2 channels) for continuous sine wave as
shown in Figure 1.
In an actual application where a music signal is used, it is
impractical to estimate the power dissipation based on the
continuous signal as shown right, because too large a heat
sink must be used. It is reasonable to estimate the power
dissipation as 1/10 Po max. (EIAJ).
That is, Pd = 21.5W at 8 Ω
IC Power dissipation, Pd - W
Thermal resistance θ c-a of a heat sink for this IC power
dissipation (Pd) is fixed under conditions 1 and 2 shown
below.
Output power, Po - W
Condition 1: T
Figure 1. STK4432 Pd – Po (R
= Pd × θ c-a + Ta ≤ 125 ° C ..............................................(1)
C
= 8 Ω )
L
where Ta : Specified ambient temperature
T
: Operating substrate temperature
C
Condition 2: T
= Pd × (θ c-a) + Pd/4 × (θ j-c) + Ta ≤ 150 ° C....................(2)
j
where Tj : Junction temperature of power transistor
Assuming that the power dissipation is shared equally among the four power transistors(2 channels × 2) , thermal resistance θ j-c is 2.8 ° C/W and
Pd × (θ c-a + 2.8/4) + Ta ≤ 150 ° C........................................(3)
No. 2885—6/7
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STK4432
Thermal resistance θ c-a of a heat sink must satisfy inequalities (1) and (3).
Figure 2 shows the relation between Pd and θ c-a given
from (1) and (3) with Ta as a parameter.
[Example] The thermal resistance of a heat sink is
obtained when the ambient temperature specified for a stereo amplifier is 50 ° C.
Assuming V
R
= 8 Ω : Pd = 21.5W at 1/10 Po max.
L
= 49V, R
CC
= 8 Ω ,
L
The thermal resistance of a heat sink is
obtained from Figure 2.
R
= 8 Ω : θ c-a = 3.49 ° C/W
L
Tj when a heat sink is used is obtained from
(3).
R
= 8 Ω : Tj = 140.1 ° C
L
Thermal resistance of heat sink, θc-a - °C/W
IC Power dissipation, Pd - W
Figure 2. STK4432
c-a – Pd
θ
■
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-pre v ention equipment and the lik e, 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 e xample 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 November, 1997. Specifications and information herein are subject to change without notice.
No. 2885—7/7
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