CIRRUS PB50

PB50
PB50
P r o d u PB50
c t IInnnnoovvaa t i o n FFr roomm
Power Booster Amplifier
FEATURES
• WIDE SUPPLY RANGE — ±30V to ±100V
• HIGH OUTPUT CURRENT — Up to 2A Continuous
• VOLTAGE AND CURRENT GAIN
• HIGH SLEW RATE —
50V/µs Minimum
• PROGRAMMABLE OUTPUT CURRENT LIMIT
• HIGH POWER BANDWIDTH — 160 kHz Minimum
• LOW QUIESCENT CURRENT — 12mA Typical
8-pin TO-3
PACKAGE STYLE CE
EQUIVALENT SCHEMATIC
APPLICATIONS
3
+Vs
• HIGH VOLTAGE INSTRUMENTATION
• Electrostatic TRANSDUCERS & DEFLECTION
• Programmable Power Supplies Up to 180V p-p
Q1
DESCRIPTION
The PB50 is a high voltage, high current amplifier designed
to provide voltage and current gain for a small signal, general
purpose op amp. Including the power booster within the feedback loop of the driver amplifier results in a composite amplifier
with the accuracy of the driver and the extended output voltage
range and current capability of the booster. The PB50 can also
be used without a driver in some applications, requiring only
an external current limit resistor to function properly.
The output stage utilizes complementary MOSFETs, providing symmetrical output impedance and eliminating secondary
breakdown limitations imposed by Bipolar Junction Transistors. Internal feedback and gainset resistors are provided for
a pin-strappable gain of 3. Additional gain can be achieved
with a single external resistor. Compensation is not required
for most driver/gain configurations, but can be accomplished
with a single external capacitor. Although the booster can
be configured quite simply, enormous flexibility is provided
through the choice of driver amplifier, current limit, supply
voltage, voltage gain, and compensation.
This hybrid circuit utilizes a beryllia (BeO) substrate, thick
film resistors, ceramic capacitors and semiconductor chips to
maximize reliability, minimize size and give top performance.
Ultrasonically bonded aluminum wires provide reliable interconnections at all operating temperatures. The 8-pin TO-3
package is electrically isolated and hermetically sealed using
one-shot resistance welding.The use of compressible isolation
washers voids the warranty.
TYPICAL APPLICATION
Q2
Q3
IN
4
Q4
GAIN 6.2K
7
Q6
50K
3.1K
OUT
1
2
CL
Q7
COM
5
COMP
8
Q8
Q9
Q10
–Vs
6
EXTERNAL CONNECTIONS
+Vs
RCL
CL
3
2
1
IN 4
CF
Q5
OUT
TOP VIEW
VIN
RI
+15V
OP
AMP
–15V
RF
+Vs
COM
RCL
IN
COM
PB50
–Vs
–Vs 6
OUT
CC
5
8
7
GAIN
COMP CC
RG
RL
RG
Figure 1. Inverting composite amplifier.
PB50U
http://www.cirrus.com
Copyright © Cirrus Logic, Inc. 2009
(All Rights Reserved)
MAY 20091
APEX − PB50UREVJ
PB50
P r o d u c t I n n o v a t i o nF r o m
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, +VS to –VS
OUTPUT CURRENT, within SOA
POWER DISSIPATION, internal at TC = 25°C1
INPUT VOLTAGE, referred to common
TEMPERATURE, pin solder—10 sec max
TEMPERATURE, junction1
TEMPERATURE, storage
OPERATING TEMPERATURE RANGE, case
200V
2A
35W
±15V
300°C
150°C
–65 to +150°C
–55 to +125°C
SPECIFICATIONS
PARAMETER
TEST CONDITIONS2
INPUT
OFFSET VOLTAGE, initial
OFFSET VOLTAGE, vs. temperature
INPUT IMPEDANCE, DC
INPUT CAPACITANCE
CLOSED LOOP GAIN RANGE
GAIN ACCURACY, internal Rg, Rf
GAIN ACCURACY, external Rf
PHASE SHIFT
OUTPUT
VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING
CURRENT, continuous
SLEW RATE
CAPACITIVE LOAD
SETTLING TIME to .1%
POWER BANDWIDTH
SMALL SIGNAL BANDWIDTH
SMALL SIGNAL BANDWIDTH
POWER SUPPLY
VOLTAGE, ±VS3
CURRENT, quiescent
THERMAL
RESISTANCE, AC junction to case4
RESISTANCE, DC junction to case
RESISTANCE, junction to air
TEMPERATURE RANGE, case
MIN
Full temperature range
25
3
AV = 3
AV = 10
F = 10kHz, AVCL = 10, CC = 22pF
F = 200kHz, AVCL = 10, CC = 22pF
Io = 2A
Io = 1A
Io = .1A
Full temperature range
Full temperature range
RL = 100Ω, 2V step
VC = 100Vpp
CC = 22pF, AV = 25, Vcc = ±100
CC = 22pF, AV = 3, Vcc = ±30
Full temperature range
VS = ±30
VS = ±60
VS = ±100
Full temp. range, F > 60Hz
Full temp. range, F < 60Hz
Full temperature range
Meets full range specifications
VS–11
VS–10
VS–8
2
50
160
±305
–25
TYP
MAX
UNITS
±.75
–4.5
50
3
10
±10
±15
10
60
±1.75
–7
25
±15
±25
V
mV/°C
kΩ
pF
V/V
%
%
°
°
VS –9
VS –7
VS –5
100
2200
2
320
100
1
V
V
V
A
V/µs
pF
µs
kHz
kHz
MHz
±60
9
12
17
±100
12
18
25
V
mA
mA
mA
1.8
3.2
30
25
2.0
3.5
85
°C/W
°C/W
°C/W
°C
NOTES: 1. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to
achieve high MTTF (Mean Time to Failure).
2. The power supply voltage specified under typical (TYP) applies, TC = 25°C unless otherwise noted.
3. +VS and –VS denote the positive and negative supply rail respectively.
4. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.
5. +VS must be at least 15V above COM, –VS must be at least 30V below COM.
CAUTION
2
The PB50 is constructed from MOSFET transistors. ESD handling procedures must be observed.
The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush, machine, or
subject to temperatures in excess of 850°C to avoid generating toxic fumes.
PB50U
PB50
R =
CL
.33
CURRENT LIMIT, ILIM (A)
Ω
–90
40
–135
20
0
100
1K
10K 100K
1M
FREQUENCY, F (Hz)
–180
10M
AVCL = 10
10
AVCL = 3
0
CC = 22pF
–10
1K
INPUT OFFSET VOLTAGE, VOS (V)
QUIESCENT CURRENT, IO (mA)
Vs = ±30V
10
0
–25
360
POWER RESPONSE
DISTORTION, THD (%)
VQ (V), P-P
45
22
PB50U
3K
10K 30K 100K 300K
FREQUENCY, F (Hz)
10M
1M
4
VO +
2
.1
.2
1
.01 .02
OUTPUT CURRENT, IO (A)
TEMP.
-1
SUPPLY
RL = 25Ω
.1
RL = 1KΩ
.01
300
1K
3K
10K
FREQUENCY, F (Hz)
30K
AVCL = 10
–135
CC = 22pF
–180
1K
10K
100K
1M
FREQUENCY, F (Hz)
10M
SLEW RATE VS. TEMP.
300
+SLEW
200
100
0
–25
.1
.3
AVCL = 3
AVCL = 25
HARMONIC DISTORTION
NO DRIVER
VS = ±60V
VO = 80VP-P
2
–90
400
0
.03
VO –
–45
INPUT OFFSET VOLTAGE
1
90
6
SMALL SIGNAL RESPONSE
-1.5
–25
0
25
50
75 100 125
CASE TEMPERATURE, TC ( C) OR VS (V)
75 100 125
50
0
25
CASE TEMPERATURE, TC (°C)
180
11
1K
100K
1M
10K
FREQUENCY, F (Hz)
–.5
5
8
0
.5
Vs = ±60V
OUTPUT VOLTAGE SWING
10
SMALL SIGNAL RESPONSE
20
QUIESCENT CURRENT
Vs = ±100V
0
50
75 100 125
25
CASE TEMPERATURE, TC (°C)
AVCL = 25
20
15
RCL = 1.5Ω
30
0
–45
60
.5
Ω
0
–25
0
25
50
75 100 125
CASE TEMPERATURE, TC (°C)
SMALL SIGNAL RESPONSE
R =
CL
.68
DISTORTION, THD (%)
0
–25
1
CLOSED LOOP PHASE, Ф (°)
10
RCL = .27Ω
SLEW RATE, SR (V/µs)
20
1.5
VOLTAGE DROP FROM SUPPLY, VS - VO (V)
CURRENT LIMIT
2
30
80
OPEN LOOP GAIN, A (dB)
POWER DERATING
40
OPEN LOOP PHASE, Ф (°)
CLOSED LOOP GAIN, A (dB)
INTERNAL POWER DISSIPATION, P(W)
P r o d u c t I n n o v a t i o nF r o m
.03
–SLEW
0
25
50
75 100 125
CASE TEMPERATURE, TC (°C)
HARMONIC DISTORTION
DRIVER = TL070
VS = ±60V
RL = 25Ω
VO = 95VP-P
.01
.003
RL = 1KΩ
.001
300
1K
10K
3K
FREQUENCY, F (Hz)
30K
3
PB50
P r o d u c t I n n o v a t i o nF r o m
GENERAL
STABILITY
Please read Application Note 1 "General Operating Considerations" which covers stability, supplies, heat sinking,
mounting, current limit, SOA interpretation, and specification
interpretation. Visit www.Cirrus.com for design tools that help
automate tasks such as calculations for stability, internal power
dissipation, current limit; heat sink selection; Apex Precision
Power’s complete Application Notes library; Technical Seminar
Workbook; and Evaluation Kits.
Stability can be maximized by observing the following
guidelines:
1. Operate the booster in the lowest practical gain.
2. Operate the driver amplifier in the highest practical effective
gain.
3. Keep gain-bandwidth product of the driver lower than the
closed loop bandwidth of the booster.
4. Minimize phase shift within the loop.
A good compromise for (1) and (2) is to set booster gain
from 3 to 10 with total (composite) gain at least a factor of 3
times booster gain. Guideline (3) implies compensating the
driver as required in low composite gain configurations. Phase
shift within the loop (4) is minimized through use of booster
and loop compensation capacitors Cc and Cf when required.
Typical values are 5pF to 33pF.
Stability is the most difficult to achieve in a configuration where
driver effective gain is unity (ie; total gain = booster gain). For
this situation, Table 1 gives compensation values for optimum
square wave response with the op amp drivers listed.
CURRENT LIMIT
OUTPUT CURRENT FROM +VS OR –VS (A)
For proper operation, the current limit resistor (RCL) must be
con­nected as shown in the external connection diagram. The
minimum value is 0.27Ω with a maximum practical value of
47Ω. For optimum reliability the resistor value should be set
as high as possible. The value is calculated as follows: +IL=
.65/RCL + .010, –IL = .65/RCL.
SOA
3
2
ST
1
DY
EA
DY
ST
AT
ST
AT
EA
DY
t=
EA
ST
ST
t=
ST
E
E
T
AT
C
E
T
C
T
C
=
=2
t=
10
20
50
ms
0m
0m
s
s
5°
85
C
°C
=
12
5°
C
.1
10
20 30 40 50
100
200 300
SUPPLY TO OUTPUT DIFFERENTIAL VOLTAGE VS — VO (V)
CF
CC
DRIVER
CCH
OP07
22p
22p
741
18p
10p
LF155
4.7p
10p
LF156
4.7p
10p
TL070
22p
15p
10p
For: RF = 33K, RI = 3.3K, RG = 22K
COMPOSITE AMPLIFIER CONSIDERATIONS
Cascading two amplifiers within a feedback loop has many
advantages, but also requires careful consideration of several
amplifier and system parameters. The most important of these
are gain, stability, slew rate, and output swing of the driver.
Operating the booster amplifier in higher gains results in a
higher slew rate and lower output swing requirement for the
driver, but makes stability more difficult to achieve.
GAIN SET
RG = [ (Av-1) • 3.1K] – 6.2K
RG + 6.2K
Av =
+1
3.1K
The booster’s closed-loop gain is given by the equation
above.The composite amplifier’s closed loop gain is determined
by the feedback network, that is: –Rf/Ri (inverting) or 1+Rf/Ri
(non-inverting). The driver amplifier’s “effective gain” is equal
to the composite gain divided by the booster gain.
Example: Inverting configuration (figure 1) with
R i = 2K, R f = 60K, R g = 0 :
Av (booster) = (6.2K/3.1K) + 1 = 3
Av (composite) = 60K/2K = - 30
Av (driver) = - 30/3 = -10
4
SR
1.5
7
>60
>60
>60
Table 1:
Typical values for case where op amp effective gain = 1.
CF
SAFE OPERATING AREA (SOA)
NOTE:The output stage is protected against transient flyback.
However, for protection against sustained, high energy flyback,
external fast-recovery diodes should be used.
FPBW
4kHz
20kHz
60kHz
80kHz
80kHz
+15V
CCH
RI
VIN
OP
AMP
RF
+Vs
RCL
IN
COM
PB50
OUT
COMP
CC
–15V
–Vs
RL
GAIN R
G
Figure 2. Non-inverting composite amplifier.
SLEW RATE
The slew rate of the composite amplifier is equal to the slew
rate of the driver times the booster gain, with a maximum value
equal to the booster slew rate.
OUTPUT SWING
The maximum output voltage swing required from the driver
op amp is equal to the maximum output swing from the booster
divided by the booster gain. The Vos of the booster must also
be supplied by the driver, and should be subtracted from the
available swing range of the driver. Note also that effects of Vos
drift and booster gain accuracy should be considered when
calculating maximum available driver swing.
PB50U
P r o d u c t I n n o v a t i o nF r o m
PB50
Contacting Cirrus Logic Support
For all Apex Precision Power 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 Cirrus Logic Sales Representative.
To find the one nearest to you, go to www.cirrus.com
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to change without notice and is provided "AS IS" without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant
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does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL APPLICATIONS”). CIRRUS PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED TO BE
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PB50U
5