Standard Products
Preliminary
PCS5038
Octal Precision Current Source
Radiation Tolerant
www.aeroflex.com/pcs
August 27, 2012
FEATURES
❑
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Radiation Performance
- Total dose > 100 krad (Si), Dose rate = 50 - 300 rads(Si)/s
Designed for temperature monitoring with Thermistors and RTDs (Resistance Temperature Detectors)
Eight high precision current sources
- One external resistor to set source current
- Source current range from 100uA to 2mA
- Accuracy to less than ± 1% over full operating
range
- Sensor voltage monitoring comparator on
each precision current source output
- Turn all eight sources ON/OFF with
ENA_PCS_H input pin
- Long term stability
- Low Drift
Internal Band Gap regulator
- High Precision 2.0V output
- Provided for use to generate V
REF
comparator
inputs
Packaging
- Hermetic ceramic
- 40 leads, 0.600"Sq x 0.120"Ht quad flat pack
- Weight: 4.5 gm max
Aeroflex Plainview’s Radiation Hardness Assurance Plan is DLA Certified to MIL-PRF-38534, Appendix G.
❑
Eight voltage monitoring comparators
- High impedance sensor interface
- Two groups of 4 comparators with separate
V
REF
and Enable input pins
- Provided for built-in monitoring of the voltage
generated by the current sources
- Can be used as an octal comparator by turning
off all current sources with ENA_PCS_H set
to logic 0
Zener protected inputs
Single +5V supply voltage
Low supply current
Designed for aerospace and high reliability space
applications
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GENERAL DESCRIPTION
The Aeroflex Plainview PCS5038 contains eight precision current sources that can be set with a single external
resistor connected to the R_Iset pin. The current source was designed for thermistor current monitor and
resistive sensor applications.
The precision current source outputs can be set to source from 100uA to 2mA each. Two-to-eight of the current
source outputs can be paralleled to produce multiple current source outputs levels. The output current of each
current source will follow the current set by the external resistor and the precision voltage at the R_Iset pin. The
output current precision is a function of the voltage at the R_Iset pin and the chosen resistor’s characteristics.
The comparator inputs will monitor the current source output voltage, with a trip point set by an external
reference voltage or the internal reference voltage.
A precision internal 2.0V reference is provided. The comparators are arranged as two banks of four with
separate Enable and voltage reference inputs. A Current Source Enable is also provided. See Figure 1. All
Enable inputs are active high. All comparators are inverting with their outputs pulled-up internally by a nominal
10k ohm resistor. Any unused current source outputs can be left open circuit without affecting other I/O’s. Each
current source output will track the other seven current source outputs as long as the voltage generated by the
resistor sensor does not exceed 2.0V below the supply voltage (V
CC
-2.0V). Higher sensor voltages can be
accomodated by increasing the supply voltage.
SCD5038 Rev B
ABSOLUTE MAXIMUM RATINGS
Parameter
Operating Case Temperature
Storage Case Temperature
Power Supply Voltages (V
CC
)
Rating
-55°C to +125°C
-65°C to +150°C
+7.0 V
DC
NOTICE: Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress rating only; functional operation
beyond the "Operation Conditions" is not recommended and extended exposure beyond the "Operation Conditions" may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC
= +5.0V
DC
±5%, T
C
= -55°C
TO
+125°C, Unless otherwise specified)
Parameter
Precision Current Source Out
100ua < I
PCS
< 2ma
External Set Resistor
Tolerance = +/- 0.1%
TC < +/- 10ppm
Current Source Matching Accuracy
Comparator In Voltage
Comparator Ref In Current
Enable Input Voltage Low
ENA_PCS_H (pin 33)
ENA_GRP1_H (pin 32)
ENA_GRP2_H (pin 31)
Enable Input Voltage High
ENA_PCS_H (pin 33)
ENA_GRP1_H (pin 32)
ENA_GRP2_H (pin 31)
Output Voltage Low
CMPout (1:8) (pins 1-4 and 12-15)
Output Voltage High
CMPout (1:8) (pins 1-4 and 12-15)
Internal Output Pull-Up Resistor
Input Open Circuit Voltage
R_Iset pin Voltage
R_Iset Temp Coefficient
Band Gap Output Voltage
BGR_VREF
(pin 26)
Band Gap Load Regulation
BGR_VREF
(pin 26)
Comparator Pulse Delay
2/
2/
2/
1/
1/
Symbol
I
PCS
ON
Condition
ENA_PCS_H = Hi
ENA_GRP1_H = Hi
ENA_GRP2_H = Hi
ENA_PCS_H = Lo
ENA_GRP1_H = Hi
ENA_GRP2_H = Hi
Relative to Mean of I
PCS
ON
(1:8)
@ 25°C
Input or Reference
VREF_GRP1 = 0V
VREF_GRP2 = 0V
Min
I
PCS
-0.75%
-
-0.75
0
-
Max
I
PCS
+0.75%
1000
0.75
3.0
2.0
Unit
mA
I
PCS
OFF
I
MATCH
V
IN
I
REF
nA
%
V
uA
V
IL
-
0.8
V
V
IH
2.0
-
V
V
OL
V
OH
R
INT
V
INOC
V
SET
V
SET
-
TC
V
BG
V
BG
I
BG
t
DLH1
t
DHL1
t
DLH2
t
DHL2
t
DLH3
t
DHL3
Isink < 2.0mA
-
4.4
8
0.4
V
V
12
V
CC
K
V
V
%
V
mV
nS
nS
nS
nS
uS
nS
@ 25°C
1.998
-0.75
1.980
2.002
0.75
2.020
5
300
200
1000
750
3.0
500
BG Iout
<
2mA
CL = 30pF, Vref = 1.0Vdc
Vin overdrive
>
50mV
See Figure 2
CL = 30pF, Vref = 1.0Vdc
Vin = 1.05vdc
See Figure 2
CL = 30pF, Vref = 1.0Vdc
Rin = 1K, R_Iset = 1K
I
PCS
= 2mA, See Figure 2
-
-
-
-
-
-
-
3/
Comparator Enablet Delay
3/
I
PCS
Enable Delay
3/
SCD5038 Rev B
Preliminary
8/27/12
Aeroflex Plainview
3
ELECTRICAL CHARACTERISTICS
(V
CC
= +5.0V
DC
±5%, T
C
= -55°C
TO
+125°C, Unless otherwise specified)
Parameter
Short Circuit Current
Output Current Noise @ 1KHz
See Curve
Supply current
2/
Symbol
I
SC
Inoise 1
Inoise 2
I
CCq
Condition
R_Iset = 0, PCS and Comparator
Groups Enabled @ 25°C
I
PCS
= 100uA @ 25°C, Typ = 11.5
I
PCS
=
2mA @ 25°C, Typ = 63.0
Min
Max
60
Unit
mA
pA/
eHz
mA
-
-
-
-
-
10
PCS and Comparator Groups
Disabled
1/
ENA_PCS_H
= Lo
ENA_GRP1_H = Lo
ENA_GRP2_H = Lo
R_Iset
I
PCS
ENA_PCS
ENA_GRP1_H
ENA_GRP2_H
CMPout(1:8)
= 1K
= 2mA
= Hi
= Hi
= Hi
= Hi
PCS and Comparator Groups
Enabled
1/
I
CC
30
mA
Notes:
1/ Hi > V
IH
, L
O
< V
IL
.
2/ Guaranteed by design, but not tested.
3/ Test fixture node capacitance plus 10pF scope capacitance.
FIGURE 2 – Timing Diagram
SCD5038 Rev B
Preliminary
8/27/12
Aeroflex Plainview
4
One primary application for the Aeroflex PCS5038, as shown in Figure 3 below, would
be to monitor the temperature of different electronic bay areas in a Satellite, and report when
any bay area has exceeded a maximum temperature limit.
Thermistors with defined temperature characteristics are used as the sensors, and by
providing a constant stable current to the external Thermistor (Temp T1 to Temp T8), an
accurate analog voltage of a specific temperature trip point can be established. The
comparator voltage reference input can be tailored to set the trip point for the characteristic of
the particular thermistor sensor used. The on-board precision 2 Volt reference can be used
directly for voltages of 2 Volts or less, or can be scaled with an external operational amplifier
to provide a voltage between 2 Volts and the maximum input of 3.0 Volts, for a +5v supply.
Various temperature trip points could be accomplished by using thermistors with different
temperature characteristics.
FIGURE 3 – Typical Temperature Sensing Application
SCD5038 Rev B
Preliminary
8/27/12
Aeroflex Plainview
5
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