USER’S MANUAL
ISL70444SEHEVAL1Z
Evaluation Board
AN1824
Rev 0.00
February 25, 2013
Introduction
The ISL70444SEHEVAL1Z evaluation platform is designed to
evaluate the ISL70444SEH. The ISL70444SEH contains four
high speed and low power op amps designed to take advantage
of its full dynamic input and output voltage range with rail-to-rail
operation. By offering low power, low offset voltage, and low
temperature drift coupled with its high bandwidth and
enhanced slew rates upwards of 50V/µs, these op amps make
it ideal for applications requiring both high DC accuracy and AC
performance. This amplifier is designed to operate over a
single supply range of 2.7V to 40V or a split supply voltage
range of ±1.35V to ±20V. The ISL70444SEH is manufactured
in Intersil’s PR40, silicon on insulator, BiCMOS process. This
process assures the device is immune to a single event
latch-up and provides excellent radiation tolerance. This
makes it the ideal choice for high reliability applications in
harsh radiation-prone environments.
Power Supply Connections
J3
V-
V+
J1
J4
VREF
C2
1µF
D2
R37
0Ω
V-
C4
0.1µF
R44
0Ω
R1
0Ω
C26
1µF
D1
GND
J2
R48
0Ω
V+
V- AND V+
IC SUPPLY PINS
C1
0.01µF
C5
0.01µF
C3
0.1µF
FIGURE 1. POWER SUPPLY CIRCUIT
Reference Documents
• ISL70444SEH Data Sheet
FN8411
• ISL70444SEH SMD
5962-13214
• ISL70444SEH
Radiation Test Report
Evaluation Board Key Features
• Single or dual supply operation: ±1.35V to ±20V or 2.7V to
40V
• Singled-ended or differential input operation with gain
(G = 10V/V)
• External VREF input
• Banana Jack connectors for power supply and VREF inputs
• BNC connectors for op amp input and output terminals
• Convenient PCB pads for op amp input/output impedance
loading
Figure 1 demonstrates the power supply connections,
decoupling and protection circuitry. External power
connections are made through the V+, V-, VREF, and GND
banana jack connections on the evaluation board. De-coupling
capacitors C2 and C26 provide low-frequency power-supply
filtering, while additional capacitors (C1, C3, C4 and C5,
connected close to the part) filter out high frequency noise,
and are connected to their respective supplies through R37
and R48 resistors. These resistors are 0Ω but can be changed
by the user to provide additional power supply filtering, or to
reduce the supply voltage rate-of-rise time. Anti-reverse diodes
D1 and D2 protect the circuit in case of momentarily reversing
the power supplies accidentally to the evaluation board. The
VREF pin can be connected to ground to establish a ground
referenced input for split supply operation.
R39, R47, R49, R50
IN-A
IN-B
IN-C
IN-D
IN+A
IN+B
IN+C
IN+D
2
6
9
13
3
5
10
12
100kΩ
R14, R16,
R18, R40
IN-
10kΩ
R5, R7,
R9, R35
IN+
VCM
VREF
10kΩ
-
4
ISL70444SEH
V+
0Ω
OUT_A
OUT_B
OUT_C
OUT_D
1 R51 TO R54
7
8
14
R67 TO R70
OPEN
OUT
IN+
+
11
V-
R32
100kΩ
R33
OPEN
VREF
GND
FIGURE 2. BASIC DIFFERENTIAL AMPLIFIER CONFIGURATION
AN1824 Rev 0.00
February 25, 2013
Page 1 of 9
ISL70444SEHEVAL1Z
Amplifier Configuration
A simplified schematic of the evaluation board is shown in
Figure 2. The input stage with the components supplied is shown
in Figure 3. The circuit implements a Hi-Z differential input with
unbalanced common mode impedance. The differential
amplifier gain is expressed in Equation 1:
V
OUT
=
V
IN+
–
V
IN-
R
F
R
IN
+
V
REF
(EQ. 1)
IN+A
R5
10kΩ
C7
OPEN
R15
DNP
0Ω
R21
C6
R6
DNP
R11
0Ω
R2
OPEN
R14
DNP
DNP
R20
10kΩ
C23
OPEN
R39
100kΩ
FROM OUT_A
IN-A
TO IN-A
TO IN+A
For a single-ended input with an inverting gain G = -10V/V, the
IN+ input is grounded and the signal is supplied to the IN- input.
VREF must be connected to a reference voltage between the
V+ and V- supply rails. For a non-inverting operation with
G = 11V/V, the negative input (IN-) is grounded and the signal is
supplied to the positive input (IN+). The non-inverting gain is
strongly dependent on any resistance from IN- to GND. For good
gain accuracy, a 0Ω resistor should be installed on the empty
R11 pad.
FIGURE 3. INPUT STAGE
OPEN
OPEN DNP
R59
DNP
Component pads are included to enable a variety of
user-selectable circuits to be added to the amplifier inputs, the
VREF input, outputs and the amplifier feedback loops.
A voltage divider can be added to establish a power
supply-tracking common mode reference using the VREF input.
The inverting and non-inverting inputs have additional resistor
and capacitor placements for adding input attenuation or
feedback capacitors (Figure 3).
The outputs (Figure 4) also have additional resistor and capacitor
placements for filtering and loading.
Note: Operational amplifiers are sensitive to output capacitance
and may oscillate. In the event of oscillation, reduce output
capacitance by using shorter cables, or add a resistor in series
with the output.
FIGURE 4. OUTPUT STAGE
AN1824 Rev 0.00
February 25, 2013
C15
DNP
C14
R55
R67
User-selectable Options
OUT_A
R51
0Ω
R63
0Ω
J13 OUT A
Page 2 of 9
ISL70444SEHEVAL1Z
TABLE 1. ISL70444SEHEVAL1Z COMPONENTS PARTS LIST
DEVICE #
C1, C5
C2, C26
C3, C4
C6 - C25
D1, D2
J1 - J4
J5 - J16
R32
R5, R7, R9, R14, R16, R18,
R35, R40
R39, R47, R49, R50
R2, R3, R4, R11, R12, R13,
R20, R21, R22, R23, R25,
R26, R28, R30, R31, R33,
R34, R38, R42, R43, R46,
R55, R56, R57, R58, R59,
R60, R61, R62, R62, R67,
R68, R69, R70
U1
DESCRIPTION
CAP, SMD, 0805, 0.01µF, 50V, 10%, X7R, ROHS
CAP, SMD, 1210, 1µF, 50V, 10%, X7R, ROHS
CAP, SMD, 0805, 0.1µF, 25V, 10%, X7R, ROHS
CAP, SMD, 0603, Open-Place Holder, ROHS
40V Schottky Barrier Diode
Johnson Components Standard Type Banana Jack, 108-0740-001
AMPHENOL BNC Connector, 31-5329-52RFX
Resistor, SMD, 0603, 100kΩ, 1%, ROHS
Resistor, SMD, 0603, 10kΩ, 1%, 1/16W, ROHS
Resistor, SMD, 0603, 100kΩ, 1%, 1/16W, ROHS
Resistor, SMD, 0603, DNP-Place Holder, ROHS
COMMENTS
Power Supply Decoupling
Power Supply Decoupling
Power Supply Decoupling
User Selectable Capacitors - Not Populated
Reverse Power Protection
Power Supply and Reference Voltage Connector
Connections for Input and Output
VREF Resistor Divider
Gain Setting Resistor
Gain Setting Feedback Resistor
User Selectable Resistors - Not Populated
ISL70444SEH, 40V Radiation Hardened, Low Noise Quad Operational
Amplifier
V
IN
V
IN
: 25mV
P-P
C1: 10mV/DIV
C2: 10mV/DIV
T: 1µs/DIV
C
L
= 20pF
V
IN
V
IN
: 10V
P-P
C1: 5V/DIV
C2: 5V/DIV
T: 1µs/DIV
C
L
= 20pF
V
OUT
V
OUT
FIGURE 5. SMALL SIGNAL STEP RESPONSE (±18V)
FIGURE 6. LARGE SIGNAL STEP RESPONSE (±18V)
AN1824 Rev 0.00
February 25, 2013
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ISL70444SEHEVAL1Z
V
IN
: 25mV
P-P
C1: 10mV/DIV
C2: 10mV/DIV
T: 1µs/DIV
C
L
= 20pF
V
IN
: 2.5V
P-P
C1: 1.26V/DIV
C2: 1.26V/DIV
T: 1µs/DIV
C
L
= 20pF
V
IN
V
IN
V
OUT
V
OUT
FIGURE 7. SMALL SIGNAL STEP RESPONSE (±2.5V)
FIGURE 8. LARGE SIGNAL STEP RESPONSE (±2.5V)
10
12pF
0
-10
GAIN (dB)
-20
-30
-40
-50
100
10
0
-10
GAIN (dB)
-20
68pF
-30
47pF
-40
100M
-50
100
ACL = 1
R
L
= 10k
V
S
= ±2.5V
1k
10k
100k
1M
FREQUENCY (Hz)
47pF
10M
100M
27pF
12pF
27pF
68pF
ACL = 1
R
L
= 10k
V
S
= ±18V
1k
10k
100k
1M
FREQUENCY (Hz)
10M
FIGURE 9. (V
S
= ±18V) UNITY GAIN RESPONSE vs CL
FIGURE 10. (V
S
= ±2.5V) UNITY GAIN RESPONSE vs CL
10
0
-10
GAIN (dB)
-20
-30
-40
-50
100
ACL = 1
R
L
= 10k
V
S
= ±1.5V
1k
10k
100k
1M
FREQUENCY (Hz)
68pF
27pF
12pF
47pF
10M
100M
FIGURE 11. (V
S
= ±1.5V) UNITY GAIN RESPONSE vs CL
AN1824 Rev 0.00
February 25, 2013
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ISL70444SEHEVAL1Z
ISL70444SEHEVAL1Z Layout
FIGURE 12. TOP VIEW
AN1824 Rev 0.00
February 25, 2013
Page 5 of 9
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