PA340 High Voltage Power Operational Amplifier

PA340 High Voltage Power Operational Amplifier
PA340
PA340
PA340
High Voltage Power Operational Amplifier
DESCRIPTION
FEATURES
The PA340 is a high voltage monolithic MOSFET operational amplifier achieving performance features previously found only in hybrid designs while increasing reliability. Inputs are protected from excessive common
mode and differential mode voltages. The safe operating area (SOA) has no second breakdown limitations.
External compensation provides the user flexibility in
choosing optimum gain and bandwidth for the application.
♦ RoHS COMPLIANT
♦ MONOLITHIC MOS TECHNOLOGY
♦ LOW COST
♦ HIGH VOLTAGE OPERATION – 350V
♦ LOW QUIESCENT CURRENT TYP. – 2.2mA
♦ NO SECOND BREAKDOWN
♦ HIGH OUTPUT CURRENT – 120 mA PEAK
APPLICATIONS
The surface mount package of the PA340CC is an industry standard non-hermetic plastic 7-pin DDPAK.
♦ TELEPHONE RING GENERATOR
♦ PIEZO ELECTRIC POSITIONING
♦ ELECTROSTATIC TRANSDUCER &
DEFLECTION
♦ DEFORMABLE MIRROR FOCUSING
♦ PACKAGING OPTIONS
7-pin DDPAK Surface Mount Package (PA340CC)
FIGURE 1: Equivalent Schematic
3
+VS
D1
Q1
Q2
Q3
Q4
6
COMP
–IN
D2
D3
D4
Q6
D5
COMP Q8
Q12
Q13
2
+IN
5
Q5
1
I OUT
7
Q11
Q10
Q14
–VS
4
SUB
Copyright © Apex Microtechnology, Inc. 2012
www.apexanalog.com
PA340U
(All Rights Reserved)
OCT 2013
PA340U REVC1
PA340
High voltage considerations should be taken when designing board layouts for the PA340. The PA340 may require a
derate in supply voltage depending on the spacing used for board layout. The 14-mil minimum spacing of the 7-pin
DDPAK is adequate to standoff the 350V rating of the PA340. However, a supply voltage derate to 250V is required
if the spacing of circuit board artwork is less than 11 mils.
The metal tab of the PA340CC package is directly tied to -Vs.
PA340CX
TYPICAL APPLICATION
PA340CC
A
A
1
1
-IN
+IN
+Vs
-Vs
OUT
COMP (Cc)
COMP (Cc)
DDPAK
PKG. STYLE CC
FIGURE 2. External Connections.
-IN
+IN
+Vs
-Vs
OUT
COMP (Cc)
COMP (Cc)
For CC values, see graph on page 4.
Note: CC must be rated for full supply voltage.
Ref: APPLICATION NOTE 20: "Bridge Mode Operation of Power Amplifiers"
Two PA340 amplifiers operated as a bridge driver for a piezo transducer provides a low cost 660 volt total drive
capability. The RN CN network serves to raise the apparent gain of A2 at high frequencies. If RN is set equal to R the
amplifiers can be compensated identically and will have matching bandwidths.
VIN
20R
20R
R
20R
+175
+175
CC
10pF
CC
10pF
A1
PA340
A2
PA340
PIEZO
TRANSDUCER
–175
LOW COST 660V p-p
PIEZO DRIVER
RN
CN
–175
FIGURE 3. Low Cost 660VP-P Piezo Driver
2
PA340U
PA340
1. CHARACTERISTICS AND SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Min
Max
Units
350
V
OUTPUT CURRENT, continuous within SOA
60
mA
OUTPUT CURRENT, peak
(Note 3)
120
mA
POWER DISSIPATION, continuous @ TC = 25°C
14
W
SUPPLY VOLTAGE, +VS to -VS
INPUT VOLTAGE, differential
-16
+16
V
INPUT VOLTAGE, common mode
-VS
+VS
V
220
°C
TEMPERATURE, pin solder - 10 sec
TEMPERATURE, junction
150
°C
TEMPERATURE, storage
(Note 2)
-65
150
°C
TEMPERATURE RANGE, powered (case)
-40
125
°C
SPECIFICATIONS (PER AMPLIFIER)
Parameter
Test Conditions (Note 1)
Min
Typ
Max
Units
OFFSET VOLTAGE, initial
12
40
mV
OFFSET VOLTAGE, vs. temperature
25°C to 85°C
(Note 3)
17
250
µV/°C
OFFSET VOLTAGE, vs. temperature
-25°C to 25°C
(Note 3)
18
500
µV/°C
OFFSET VOLTAGE, vs. supply
4.5
OFFSET VOLTAGE, vs. time
80
BIAS CURRENT, initial
50
BIAS CURRENT, vs. supply
2
INPUT
OFFSET CURRENT, initial
50
INPUT IMPEDANCE, DC
INPUT CAPACITANCE
µV/V
µV/kh
200
pA
pA/V
200
pA
1011
Ω
3
pF
COMMON MODE, voltage range
+VS - 12
V
COMMON MODE, voltage range
-VS + 12
V
COMMON MODE REJECTION, DC
VCM = ±
­ 90VDC
NOISE, broad band
10kHz BW, RS = 1KΩ
84
115
dB
337
µV RMS
GAIN
OPEN LOOP at 15Hz
RL = 5KΩ
103
dB
GAIN BANDWIDTH PRODUCT
@1MHz
10
MHz
POWER BANDWIDTH
280V p-p
35
kHz
PA340U
90
3
PA340
Parameter
Test Conditions (Note 1)
Min
Typ
Max
Units
OUTPUT
VOLTAGE SWING
CURRENT, peak
IO = 40mA
(Note 3)
CURRENT, continuous
SETTLING TIME to 0.1%
SLEW RATE
±VS
12
±VS
10
V
120
mA
60
mA
10V step, A V = -10
2
µs
CC = 4.7pF
32
V/µS
RESISTANCE, 10mA
(Note 4) RCL = 0Ω
91
Ω
RESISTANCE, 40mA
(Note 4) RCL = 0Ω
65
Ω
POWER SUPPLY
VOLTAGE
±10
CURRENT, quiescent
±150
±175
V
2.2
2.5
mA
THERMAL
RESISTANCE, AC junction to case
F > 60Hz
5.9
6.85
°C/W
RESISTANCE, DC junction to case
F < 60Hz
7.7
8.9
°C/W
RESISTANCE, junction to air
Full temperature range
(Note 5)
TEMPERATURE RANGE, case
Meets full range specifications
27
-25
25
°C/W
+85
°C
NOTES:
1. Unless otherwise noted TC = 25°C, CC = 6.8pF. DC input specifications are ± value given. Power supply voltage is typical rating.
2. Long term operation at the maximum junction temperature will result in reduced product life. Derate
internal power dissipation to achieve high MTTF. For guidance, refer to heatsink data sheet.
3. Guaranteed but not tested.
4. Since the PA340 has no current limit, load impedance must be large enough to limit output current to
120mA. 5. Heat tab attached to 3/32" FR-4 board with 2oz. copper. Topside copper area (heat tab directly attached) = 1000 sq. mm, backside copper area = 2500 sq. mm, board area = 2500 sq. mm.
CAUTION
The PA340 is constructed from MOSFET transistors. ESD handling procedures must be observed.
4
PA340U
PA340
8
6
4
[email protected]°C
15
[email protected]°C
10
5
2
0
25
50
75
100
TEMPERATURE, T (°C)
0
125
-80
-90
100
PHASE, Φ (°)
60
2.2pF
40
0.75pF
-110
2.2pF
6.8pF
-140
-150
68pF
15pF
-160
0
-170
-20
10
10
68pF
-130
15pF
20
PHASE RESPONSE
-120
6.8pF
100 1K 10K 100K 1M 10M
FREQUENCY, F (Hz)
-180
10K
100K
1M
FREQUENCY, F (Hz)
HARMONIC DISTORTION
10M
SLEW RATE
0.01
A V = 20
C C = 15pF
R L = 2K
1K
10K
FREQUENCY, F (Hz)
SLEW RATE, (V/µs)
0.1 180V
P-P
0.001
100
COMMON MODE REJECTION, CMR (dB)
30VP-P
60VP-P
100
80
60
40
20
0
10
100
1K
10K
FREQUENCY, F (Hz)
100K
10
RISE
5 15 25 35 45 55 65 75 85
COMPENSATION CAPACITANCE, CC (pF)
10
25°C
55°C
1
1000
1
GAIN
10
POWER RESPONSE
2.2pF
6.8pF
15pF
100
33pF
68pF
10
10K
100K
FREQUENCY, F (Hz)
1M
QUIESCENT CURRENT
102
100
5°C
12
C
25°
98
°C
-40
96
20 60 100 140 180 220 260 300 340
TOTAL SUPPLY VOLTAGE, (V)
POWER SUPPLY REJECTION
COMMON MODE REJECTION
120
FALL
20
0
100K
POWER SUPPLY REJECTION, PSR (dB)
DISTORTION, (%)
30
1
125°C
85°C
0.1
0.1
20
40
60
80 100 120
OUTPUT CURRENT, IO (mA)
-100
0.75pF
80
[email protected]°C
0
SMALL SIGNAL RESPONSE
OPEN LOOP GAIN, A (dB)
20
COMPENSATION, pF
10
GAIN AND COMPENSATION
[email protected]°C
25
12
100
OUTPUT VOLTAGE, (VOUT) (p-p)
14
0
OUTPUT VOLTAGE SWING
30
NORMALIZED QUIESCENT CURRENT, IQ (%)
POWER DERATING
16
VDROP FROM VS, (V)
INTERNAL POWER DISSIPATION, P(W)
2. TYPICAL PERFORMANCE GRAPHS
100
POSITIVE
90
80
70
NEGATIVE
60
50
40
10
100
1K
10K
FREQUENCY, F (Hz)
PA340U
100K
5
PA340
3.
APPLICATION INFORMATION
3.1
PHASE COMPENSATION
3.2
OTHER STABILITY CONCERNS
Please read Application Note 1 "General Operating Considerations" which covers stability, power supplies, heat
sinking, mounting, current limit, SOA interpretation, and specification interpretation. Visit www.apexanalog.com
for design tools that help automate tasks such as calculations for stability, internal power dissipation, current limit,
heat sink selection, Apex Microtechnology's complete Application Notes library, Technical Seminar Workbook and
Evaluation Kits.
Open loop gain and phase shift both increase with increasing temperature. The PHASE COMPENSATION typical
graph shows closed loop gain and phase compensation capacitor value relationships for four case temperatures.
The curves are based on achieving a phase margin of 50°. Calculate the highest case temperature for the application (maximum ambient temperature and highest internal power dissipation) before choosing the compensation.
Keep in mind that when working with small values of compensation, parasitics may play a large role in performance
of the finished circuit. The compensation capacitor must be rated for at least the total voltage applied to the amplifier
and should be a temperature stable type such as NPO or COG.
There are two important concepts about closed loop gain when choosing compensation. They stem from the fact
that while "gain" is the most commonly used term, β (the feedback factor) is really what counts when designing for
stability.
1. Gain must be calculated as a non-inverting circuit (equal input and feedback resistors can provide a signal gain
of -1, but for calculating offset errors, noise, and stability, this is a gain of 2).
2. Including a feedback capacitor changes the feedback factor or gain of the circuit. Consider RIN = 4.7k, Rf = 47k
for a gain of 11. Compensation of 4.7 to 6.8pF would be reasonable. Adding 33pF parallel to the 47K rolls off the
circuit at 103kHz, and at 2MHz has reduced gain from 11 to roughly 1.5 and the circuit is likely to oscillate.
As a general rule the DC summing junction impedance (parallel combination of the feedback resistor and all input
resistors) should be limited to 5K ohms or less. The amplifier input capacitance of about 6pF, plus capacitance of
connecting traces or wires and (if used) a socket will cause undesirable circuit performance and even oscillation if
these resistances are too high. In circuits requiring high resistances, measure or estimate the total sum point capacitance, multiply by RIN /Rf, and parallel Rf with this value. Capacitors included for this purpose are usually in the
single digit pF range. This technique results in equal feedback factor calculations for AC and DC cases. It does not
produce a roll off, but merely keeps β constant over a wide frequency range. Paragraph 6 of Application Note 19
details suitable stability tests for the finished circuit.
SAFE OPERATING AREA
The MOSFET output stage of the PA340 is not limited by second
breakdown considerations as in bipolar output stages. However
there are still three distinct limitations:
1. Voltage withstand capability of the transistors.
2. Current handling capability of the die metallization.
3. Temperature of the output MOSFETS.
SOA
1.0
OUTPUT CURRENT FROM +VS OR –VS, (A)
3.3
0.5
0.3
0.2
200mS
300mS
0.1
0.05
0.03
0.02
DC, TC = 25°C
These limitations can be seen in the SOA (see Safe Operating Area
DC, TC = 85°C
graphs). Note that each pulse capability line shows a constant power
0.01
level (unlike second breakdown limitations where power varies with
0.005
voltage stress). These lines are shown for a case temperature of
0.003
25°C. Pulse stress levels for other case temperatures can be calcu0.002
lated in the same manner as DC power levels at different tempera0.001
tures. The output stage is protected against transient flyback by the
10
20 30 50
100 200 300 500
1K
parasitic diodes of the output stage MOSFET structure. However,
SUPPLY TO OUTPUT DIFFERENTIAL, VS - VO, (V)
for protection against sustained high energy flyback external fastFIGURE 4. Safe Operating Area
recovery diodes must be used.
6
PA340U
PA340
3.4HEATSINKING
The PA340CC 7-pin DDPAK surface mountable package has a large exposed integrated copper heatslug to which
the monolithic amplifier is directly attached. The PA340CC requires surface mount techniques of heatsinking. A solder connection to a copper foil area as defined in Note 5 of Page 3 is recommended for circuit board layouts. This
may be adequate heatsinking but the large number of variables suggests temperature measurements to be made
on the top of the package. Do not allow the temperature to exceed 85°C.
3.5
OVERVOLTAGE PROTECTION
Although the PA340 can withstand differential input voltages up to 16V, in
some applications additional external protection may be needed. Differential inputs exceeding 16V will be clipped by the protection circuitry. However, if more than a few milliamps of current is available from the overload
source, the protection circuitry could be destroyed. For differential sources
above 16V, adding series resistance limiting input current to 1mA will prevent damage. Alternatively, 1N4148 signal diodes connected anti-parallel
across the input pins is usually sufficient. In more demanding applications
where bias current is important, diode connected JFETs such as 2N4416
will be required. See Q1 and Q2 in Figure 5. In either case the differential
input voltage will be clamped to 0.7V. This is sufficient overdrive to produce
the maximum power bandwidth.
+Vs
+Vs
-IN
Q1
+IN
Z1
OUT
Q2
-Vs
-Vs
Z2
In the case of inverting circuits where the +IN pin is grounded, the diodes
FIGURE 5. Overvoltage Protection
mentioned above will also afford protection from excessive common mode
voltage. In the case of non-inverting circuits, clamp diodes from each input to each supply will provide protection.
Note that these diodes will have substantial reverse bias voltage under normal operation and diode leakage will
produce errors.
Some applications will also need over-voltage protection devices connected to the power supply rails. Unidirectional
zener diode transient suppressors are recommended. The zeners clamp transients to voltages within the power
supply rating and also clamp power supply reversals to ground. Whether the zeners are used or not the system
power supply should be evaluated for transient performance including power-on overshoot and power-off polarity
reversals as well as line regulation. See Z1 and Z2 in Figure 5.
NEED TECHNICAL HELP? CONTACT APEX SUPPORT!
For all Apex Microtechnology product questions and inquiries, call toll free 800-546-2739 in North America.
For inquiries via email, please contact [email protected]
International customers can also request support by contacting their local Apex Microtechnology Sales Representative.
To find the one nearest to you, go to www.apexanalog.com
IMPORTANT NOTICE
Apex Microtechnology, Inc. has made every effort to insure the accuracy of the content contained in this document. However, the information is subject to change
without notice and is provided "AS IS" without warranty of any kind (expressed or implied). Apex Microtechnology reserves the right to make changes without further
notice to any specifications or products mentioned herein to improve reliability. This document is the property of Apex Microtechnology and by furnishing this information, Apex Microtechnology grants no license, expressed or implied under any patents, mask work rights, copyrights, trademarks, trade secrets or other intellectual
property rights. Apex Microtechnology owns the copyrights associated with the information contained herein and gives consent for copies to be made of the information only for use within your organization with respect to Apex Microtechnology integrated circuits or other products of Apex Microtechnology. This consent does not
extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.
APEX MICROTECHNOLOGY PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN PRODUCTS USED FOR
LIFE SUPPORT, AUTOMOTIVE SAFETY, SECURITY DEVICES, OR OTHER CRITICAL APPLICATIONS. PRODUCTS IN SUCH APPLICATIONS ARE UNDERSTOOD TO BE FULLY AT THE CUSTOMER OR THE CUSTOMER’S RISK.
Apex Microtechnology, Apex and Apex Precision Power are trademarks of Apex Microtechnolgy, Inc. All other corporate names noted herein may be trademarks
of their respective holders.
Copyright © Apex Microtechnology, Inc. 2012
www.apexanalog.com
PA340U
(All Rights Reserved)
OCT 2013
7
PA340U REVC
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