ETC PA34

POWER OPERATIONAL AMPLIFIERS
PA34
M I C R O T E C H N O L O G Y
HTTP://WWW.APEXMICROTECH.COM
(800) 546-APEX
(800) 546-2739
PRELIMINARY
FEATURES
• LOW COST
• WIDE COMMON MODE RANGE —
Includes negative supply
• WIDE SUPPLY VOLTAGE RANGE
Single supply: 5V to 40V
Split supplies: ±2.5V to ±20V
• HIGH EFFICIENCY — |Vs–2.2V| at 2.5A typ
• HIGH OUTPUT CURRENT — 2.5A min
• INTERNAL CURRENT LIMIT
• LOW DISTORTION
APPLICATIONS
Graphic for PA34
Here
EXTERNAL CONNECTIONS
C
PA34
• HALF & FULL BRIDGE MOTOR DRIVERS
• AUDIO POWER AMPLIFIER
STEREO — 18W RMS per channel
BRIDGE — 36W RMS per package
• IDEAL FOR SINGLE SUPPLY SYSTEMS
5V — Peripherals
12V — Automotive
28V — Avionic
5
6
7
+VS
VBOOST
4
OUT
3
-VS
2
ISENSE
1
-IN
The PA34 consist of a monolithic power op amp in a
7-pin T0220 package.
The wide common mode input range includes the negative
rail, facilitating single supply applications. It is possible
to have a “ground based” input driving a single supply
amplifier with ground acting as the “second” or “bottom”
supply of the amplifier.
The output stage is also well protected. They possess
internal current limit circuits. While the device is well protected,
the Safe Operating Area (SOA) curve must be observed.
Proper heatsinking is required for maximum reliability.
The tab of the 7 pin plastic package is tied to –VS.
+IN
DESCRIPTION
APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected]
1
PA34
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, total
OUTPUT CURRENT
POWER DISSIPATION, internal (per amplifier)
INPUT VOLTAGE, differential
INPUT VOLTAGE, common mode
JUNCTION TEMPERATURE, max1
TEMPERATURE, pin solder—10 sec max
TEMPERATURE RANGE, storage
OPERATING TEMPERATURE RANGE, case
PA34
SPECIFICATIONS
TEST CONDITIONS 2
PARAMETER
5V to 40V
SOA
25W
±VS
+VS, -VS–.5V
150°C
300°C
–65°C to 150°C
–55°C to 125°C
MIN
TYP
MAX
UNITS
1.5
15
1000
10
mV
µV/°C
INPUT
OFFSET VOLTAGE, initial
OFFSET VOLTAGE, vs. temperature
BIAS CURRENT, initial
COMMON MODE RANGE
COMMON MODE REJECTION, DC
POWER SUPPLY REJECTION
Full temperature range
Full temperature range
Full temperature range
Full temperature range
35
–VS–.3
60
60
nA
+VS–2
85
80
dB
dB
dB
100
600
65
13.6
dB
kHz
°
kHz
3.0
1.2
.22
|VS| –0.8
|VS| –1.4
|VS| –2.8
A
A
V/µs
µF
V
V
V
V
GAIN
OPEN LOOP GAIN
GAIN BANDWIDTH PRODUCT
PHASE MARGIN
POWER BANDWIDTH
Full temperature range
AV = 40dB
Full temperature range
VO(P-P) = 28V
80
OUTPUT
CURRENT, peak
CURRENT, limit
SLEW RATE
CAPACITIVE LOAD DRIVE
VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING
2.5
.5
AV = 1
Full temp. range, IO = 100mA
Full temp. range, IO = 1A
IO = 2.5A
IO = 3.0A
|VS| –1.0
|VS| –1.8
|VS| –3.0
POWER SUPPLY
54
VOLTAGE, VSS3
CURRENT, quiescent, total
30
45
40
90
V
mA
85
°C/W
°C/W
°C/W
°C
THERMAL
RESISTANCE, DC junction to case
RESISTENCE,AC junction to case
RESISTANCE, junction to air
TEMPERATURE RANGE, case
5.0
3.7
30
Meets full range specifications
–25
NOTES:
1.
2.
3.
4.
Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation
to achieve high MTTF.
Unless otherwise noted, the following conditions apply: ±VS = ±15V, TC = 25°C.
+VS and –VS denote the positive and negative supply rail respectively. VSS denotes the total rail-to-rail supply voltage.
Current limit may not function properly below VSS = 6V, however SOA violations are unlikely in this area.
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
2
PA34
30
25
20
15
10
5
0
25
50
75 100 125 150
TEMPERATURE, T (°C)
0
1.5
1.25
1.0
.75
.5
.25
–50 –25 0 25 50 75 100 125
CASE TEMPERATURE, TC (°C)
SMALL SIGNAL RESPONSE
–60
60
PHASE, ϕ (°)
40
20
0
–90
–120
–150
–180
–20
1
10
100 1K 10K 100K 1M
FREQUENCY, F (Hz)
–210
0
POWER SUPPLY REJECTION
10
100 1K 10K .1M
FREQUENCY, F (Hz)
PULSE RESPONSE
89
OUTPUT VOLTAGE, VO (V)
83
80
77
74
71
5
0
–5
69
66
63
60
AV = 1
R L =10 Ω
10
86
1M
VOLTAGE DROP FROM SUPPLY, (V)
OPEN LOOP GAIN, A (dB)
–30
80
–10
0
10 100 1K 10K 100K 1M
FREQUENCY, F (Hz)
0
200
400
600
TIME, t (µs)
800
40
30
25
20
15
10
|+VS | + |–VS | = 40V
5
1K
PHASE RESPONSE
0
100
POWER SUPPLY REJECTION, PSR (dB)
50
OUTPUT VOLTAGE, VO (VPP )
35
POWER RESPONSE
BIAS CURRENT
1.75
NORMALIZED CURRENT LIMIT, I LIM (A)
POWER DERATING
40
NORMALIZED BIAS CURRENT, I B (X)
INTERNAL POWER DISSIPATION, P(W)
TYPICAL PERFORMANCE
GRAPHS
1K
10K
FREQUENCY, F (Hz)
100K
C
CURRENT LIMIT
1.6
1.4
1.2
1.0
.8
.6
.4
25 50 75 100 125
–50 –25 0
CASE TEMPERATURE, TC (°C)
OUTPUT VOLTAGE SWING
3.5
3
2.5
2
1.5
1
.5
0
0
.5 1 1.5 2 2.5 3
OUTPUT CURRENT, I (A)
3.5
1
AV = –10
V OUT = 16VPP
RL = 8Ω
.1
.01
.001
10
100
1K
10K 40K
FREQUENCY, F (Hz)
TOTAL SUPPLY VOLTAGE, VSS (V)
3
QUIESCENT CURRENT
40
125
35
100
30
75
25
50
20
25
15
0
10
–25
CASE TEMPERATURE, TC (°C)
TOTAL HARMONIC DISTORTION, THD (%)
O
HARMONIC DISTORTION
5
–50
.7 .8
.9
1 1.1 1.2 1.3 1.4
NORMALIZED QUIESCENT CURRENT, I Q (X)
APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL [email protected]
3
OPERATING
CONSIDERATIONS
PA34
GENERAL
Please read Application Note 1 "General Operating
Considerations" which covers stability, supplies, heat sinking,
mounting, current limit, SOA interpretation, and specification
interpretation. Visit www.apexmicrotech.com for design tools
that help automate tasks such as calculations for stability,
internal power dissipation, current limit and heat sink
selection. The "Application Notes" and "Technical Seminar"
sections contain a wealth of information on specific types of
applications. Package outlines, heat sinks, mounting hardware
and other accessories are located in the "Packages and
Accessories" section. Evaluation Kits are available for most
Apex product models, consult the "Evaluation Kit" section for
details. For the most current version of all Apex product data
sheets, visit www.apexmicrotech.com.
CURRENT LIMIT
Current limit is internal to the amplifier, the typical value is
shown in the current limit specification.
3
DC
NOTE: For protection against sustained, high energy flyback,
external fast-recovery diodes should be used.
MONOLITHIC AMPLIFIER
STABILITY CONSIDERATIONS
All monolithic power op amps use output stage topologies
that present special stability problems. This is primarily due
to non-complementary (both devices are NPN) output
stages with a mismatch in gain and phase response for
different polarities of output current. It is difficult for the
op amp manufacturer to optimize compensation for all
operating conditions.
The recommended R-C network of 1 ohm in series with
0.1µF from output to AC common (ground or a supply rail,
with adequate bypass capacitors) will prevent local output
stage oscillations.
The amplifiers are internally compensated for unity gain
stability, no additional compensation is required.
s
m
2
1
OUTPUT CURRENT FROM +V S OR –VS (A)
4
allowing the output voltage to drop more than 6V below the
supply rail while the amplifier is current limiting, the inductor
should be capacitively coupled or the supply voltage must be
lowered to meet SOA criteria.
THERMAL CONSIDERATIONS
1
The PA34 may require a thermal washer which is electrically
insulating since the tab is tied to –VS. This can result in thermal
impedances for R θCS of up to 1°C/W or greater.
VBOOST
+VS
T C = 25°C
.1
1
2
3
4 5 6
10
20
30 40 50
SUPPLY TO OUTPUT DIFFERENTIAL VOLTAGE V S –VO (V)
– IN
+IN
SAFE OPERATING AREA (SOA)
The SOA curves combine the effect of all limits for this
power op amp. For a given application, the direction and
magnitude of the output current should be calculated or
measured and checked against the SOA curves. This is
simple for resistive loads but more complex for reactive and
EMF generating loads. The following guidelines may save
extensive analytical efforts.
Under transient conditions, capacitive and dynamic*
inductive loads up to the following maximum are safe:
±Vs
CAPACITIVE LOAD
INDUCTIVE LOAD
20V
15V
10V
5V
200µF
500µF
5mF
50mF
7.5mH
25mH
35mH
150mH
* If the inductive load is driven near steady state conditions,
OUT
ISENSE
RS
– VS
FIGURE 2. EQUIVALENT SCHEMATIC
ADDITIONAL PA34 PIN FUNCTIONS
VBOOST
The VBOOST pin is the positive terminal for the load of the
second stage of the amplifier. When that terminal is connected
to a voltage greater than +VS it will provide more drive to the
upper output transistor, which is a darlington connected emitter
follower. This will better saturate the output transistor.
When VBOOST is about 5 Volts greater than +VS the
positive output can swing 0.5 Volts closer to the rail. This is
as much improvement as is possible.
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
4
OPERATING
CONSIDERATIONS
PA34
+VS ≤ 20V
DB1
7
Using this voltage as a feedback source allows expressing
the gain of the circuit in amperes vs input voltage. The transfer
funcion is approximately:
DB2
3
10
IL= (VIN – VREF) *RIN/ RFB/ Rs
CB1
In the illustration, resistors RIN, RFB and RS determine
gain.
5
CB2
SPEAKER
8
+VS
FIGURE 3. SIMPLE BOOTSTRAPPING IMPROVES POSITIVE
OUTPUT SWING. CONNECT PINS 3 AND 10 TO VS IF NOT
USED. TYPICAL CURRENTS ARE 12mA EACH.
VBOOST pin requires approximately 10–12mA of current.
Dynamically it represents 1K Ω impedance. The maximum
voltage that can be applied to VBOOST is 40 volts with
respect to –VS . There is no limit to the difference between
+VS and VBOOST.
Figure 3 shows a bootstrap which dynamically couples the
output waveform onto the VBOOST pin. This causes VBOOST
to swing positive from it's initial value, which is equal to +VS
-0.7 V (one diode drop), an amount equal to the output. In
other words, if VBOOST was initially 19.3, and the output
swings positive 18 Volts, the voltage on the VBOOST pin
will swing to 19.3 -0.7 + 18 or 36.6. The capacitor needs
to be sized based on a 1K Ω impedance and the lowest
frequency required by the circuit. For example, 20Hz will
require > 8uF.
ISENSE
The ISENSE pin is in series with the negative half of the
output stage only. Current will flow through this pin only when
negative current is being outputted. The current that flows
in this pin is the same current that flows in the output (if
–1A flows in the output, the ISENSE pin will have 1A of
current flow, if +1A flows in the output the ISENSE pin will
have 0 current flow).
The resistor choice is arbitrary and is selected to provide
whatever voltage drop the engineer desires, up to a maximum
of 1.0 volt. However, any voltage dropped across the resistor
will subract from the swing to rail. For instance, assume a
+/–12 volt power supply and a load that requires +/–1A. With
no current sense resistor the output could swing +/–10.2
volts. If a 1 Ω resistor is used for current sense (which
will drop 1 Volt at 1 Amp) then the output could swing
+10.2, –9.2 Volts.
Figure 4 shows the PA34 ISENSE feature being used to
obtain a Transconductance function. In this example, amplifier
"A" is the master and amplifier "B" is the slave. Feedback
from sensing resistors RS is applied to the summing network
and scaled to the inverting input of amplifier "A" where it is
compared to the input voltage. The current sensing feedback
imparts a Transconductance feature to the amplifiers transfer
function. In other words, the voltage developed across the
sensing resistors is directly proportional to the output current.
VBIAS
C
B
R
RL
VIN
IL
R
A
RFB
RIN
RS
RS
–VS OR GND
RIN
RFB
VREF
FIGURE 4. ISENSE TRANSCONDUCTANCE BRIDGING
AMPLIFIER
VBIAS should be set midway between +Vs and -Vs, Vref
is usually ground in dual supply systems or used for level
translation in single supply systems.
MOUNTING PRECAUTIONS
1. Always use a heat sink. Even unloaded, the PA34 can
dissipate up to 3.6 watts. A thermal washer or thermal
grease should always be used.
2. Avoid bending the leads. Such action can lead to internal
damage.
3. Always fasten the tab to the heat sink before the leads are
soldered to fixed terminals.
4. Strain relief must be provided if there is any probability of
axial stress to the leads.
This data
sheet has been carefully
checked and is believed
to be reliable,
however,
no responsibility
assumed
for possible•inaccuracies
or omissions.
All specifi
subject to change without notice.
APEX
MICROTECHNOLOGY
CORPORATION
• TELEPHONE
(520)
690-8600
• FAX is(520)
888-3329
ORDERS (520)
690-8601
• cations
[email protected]
PA34U REV. 1 JANUARY 2001© 2001 Apex Microtechnology Corp.
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