CAT102
© 2009 SCILLC. All rights reserved. 1 Doc. No. MD-4007 Rev. P
Characteristics subject to change without notice
Precision, Adjustable Shunt Regulator
(600 mV Reference)
FEATURES
600 mV low voltage reference
±6 mV initial accuracy
High PSRR: 45 dB at 300 kHz
Better line regulation: 1 mV (VIN from 2.2 V to 18 V)
Low supply current: 90 µA
Open drain output
Directly driv es optocouplers
Industrial temperature range of -40ºC to 85ºC
RoHS-compliant 5-lead TSOT23 package
APPLICATION
SMPS control loop
Low temperature coefficient voltage reference
Power management
Replaces zener diodes
Isolated DC-to-DC conv erters
Network, telecom and cellular base station
Adjustable voltage reference
DESCRIPTION
The CAT102 is a low-voltage reference and amplifier.
Designed for the control loop of low-voltage power
supplies, the reference voltage has been designed for
600 mV. Over a temperature from -40°C to 85°C, the
reference voltage is within 8 mV of the nominal
600mV. In addition, the error amplifier output and the
supply voltage pin (IN) are on separate pins.
Power supply rejection is a high 45 dB at 300 kHz.
The output, OUT, can sink 20 mA at a maximum
saturation voltage of 250 mV.
When combined with an optocoupler, the CAT102 can
be used as an error amplifier that controls the
feedback loop in isolated low-output voltage switching
power supplies.
For Ordering Information details, see page 7.
FUNCTIONAL DIAGRAM PIN CONFIGURATION
TSOT-23 5L
Top View
FB 11 5 8 IN
GND 22
OUT 43 4 5 NC
PIN DESCRIPTION
Pin Name Function
FB Inverting input to error amplifier
GND Ground
OUT Output of error amplifier. Source & sink
current capability is 20 mA.
NC No connection
IN Positive supply
+
–
+
–
OUT
FB
IN
V
REF
600mV
Error
Amplifier
GND
3
5
2
1
CAT102
Doc. No. MD-4007 Rev. P 2 © 2009 SCILLC. All rights reserved.
Characteristics subject to change without notice
ABSOLUTE MAXIMUM RATINGS (1)
Parameters Ratings Units
VIN Voltage 20 V
OUT Voltage 20 V
FB Voltage 20 V
VIN, OUT, FB Current 50 mA
Operating Junction Temperature (10 seconds) 150 ºC
Lead Soldering Temperature (10 seconds) 260 ºC
Storage Temperature Range -65 to +150 ºC
ELECTRICAL CHARACTERISTICS
Electrical characteristics are guaranteed over the full operating temperature range of -40°C to +85°C unless
otherwise specified. Ambient temperature must be de-rated based upon power dissipation and package thermal
characteristics.1 Unless otherwise stated, test conditions are VIN = 3 V, FB = OUT, IOUT = 1 mA.
Symbol Parameter Conditions Min Typ Max Units
VIN Supply Voltage Range 2.2 18 V
IIN Quiescent Supply Current VOUT =1 V 90 500 µA
TJ = 25ºC 594 600 606
VFB FB Threshold Reference Voltage -40ºC < TJ < 85ºC 592 608 mV
Line Regulation VIN = 2.2 V to VIN =18 V
VOUT = 0.6 V 0.5 1 mV
Load Regulation IOUT = 1 mA to 10 mA
VOUT = 0.6 V 3 8 mV
IFB FB Input Current -500 500 nA
PSRR (3) Reference Power Supply
Rejection Frequency = 300 kHz 35 65 dB
AV Error Amplifier Open Loop Gain IOUT = 2 mA, VOUT = 1 V 60 80 dB
BW (3) Unity Gain Frequency IOUT = 2 mA, VOUT = 1 V 1 2 MHz
VOUT Output Saturation voltage IOUT = 20 mA, VFB = HIGH 130 250 mV
TRANSC (3) Output Transconductance IOUT = 1 mA to 20 mA 2.5 mA/mV
ILEAK Output Leakage Current VOUT = 16 V, VFB = 0 0.5 2 µA
IOUT(MAX) Maximum Output Current VOUT = 0.3 V 20 mA
Notes:
(1) These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolongued time periods
may affect device reliability. All voltages are with respect to ground.
(2) Thermal Characteristics (JA) of TSOT-23 5-lead: 255°C/W
(3) This parameter is controlled by design and verified during product evaluation. It is not production tested.
CAT102
© 2009 SCILLC. All rights reserved. 3 Doc. No. MD-4007 Rev. P
Characteristics subject to change without notice
TYPICAL PERFORMANCE CHARACTERISTICS
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
2 6 10 14 18 1 5 10 15 20
Supply Voltage (V)
0
1
2
3
4
5
6
Load Current (mA)
Load Regul ationLine Regulation (at 1mA)
-100
-95
-90
-85
-80
-75
-70
-65
-60
-55
-50
0.1 1 10 100 1000 10000 100000
Power-Supply Rejection Ratio vs. Frequency
)zH(ycneuqerF
Output Voltage Change (mV)
PSRR (dB) Output Voltage Change (mV)
Supply current vs. Input Voltage
78
80
82
84
86
88
90
92
0 5 10 15 20
Input Voltage (V)
Supply Current (µA)
-10
10
30
50
70
90
110
0.01 0.1 1 10 100 1000 10000
Frequency (kHz)
Gain vs. Frequency
Gain (dB)
Reference Voltage
570
580
590
600
610
620
630
-40 0 40 80 120
Junction Temperature (ºC)
Reference Voltage (mV)
CAT102
Doc. No. MD-4007 Rev. P 4 © 2009 SCILLC. All rights reserved.
Characteristics subject to change without notice
APPLICATIONS INFORMATION
The CAT102 adjustable shunt regulator features
isolated supply inputs and outputs, ideal for isolated
power-supply applications using an optocoupler in
the feedback path. The CAT102 sinks 20 mA with
VOUT at 0.3 V. The wide input supply range allows
the device to operate from 2.2 V to 18 V. The
CAT102 compares the FB input to a precision
600mV reference. If the FB input is low, the OUT pin
sinks no current. If FB rises above 600 mV, the OUT
pin sinks up to 20 mA.
Figure 1 shows the CAT102 configured as a shunt
regulator. To generate an output voltage of 0.6 V,
the FB pin has to be directly connected to the OUT
pin. A 1.0 µF capacitor from OUT to GND is
recommended when the output voltage is 0.6 V. A
resistor-divider connected from OUT to GND is used
to produce a higher output voltage as set by the
following equation:
VOUT = (1 + R1/R2) x 0.6 V
The current limit can be adjusted by using a resistor R3
connected between the IN and OUT pins. For example,
a 3.3 V supply VIN is associated with R3 = 135 , and a
10 V supply works best with R3 = 470 . The CAT102
shunt regulator is limited to low-current applications with
the OUT pin capable of sinking up to 20 mA max.
Figure 1. Application circuits for 0.6 V output and 1.2 V output voltages
CAT102
IN
GND
C
1
V
IN
3.3V 0.6V/20mA
V
OUT
0.1µF
C
2
1µF
OUT
FB
R
3
3
1
5
2
3
1
5
2
CAT102
IN
GND
C
1
V
IN
3.3V 1.2V/20mA
V
OUT
= (1 + R
1
/R
2
) x 0.6
V
0.1µF
C
2
1µF
OUT
FB
R
1
10k
10k
R
2
R
3
CAT102
© 2009 SCILLC. All rights reserved. 5 Doc. No. MD-4007 Rev. P
Characteristics subject to change without notice
TYPICAL APPLICATION
Figure 2. Opto-Feedback Application Circuit
In order to allow proper operation of the optocoupler and the CAT102, the supply voltage VCC must be greater
than 2.2 V.
V
OUT
V
IN
Regulator
with
Isolation
Opto-isolator
V
CC
> 2.2V
5
2
3
1
R3
100
R4
100k
R1
22k
R2
33k
1V regulated
outpu
t
CAT102
IN
GND
C1
0.1µF
C2
1µF
OUT
FB
CAT102
Doc. No. MD-4007 Rev. P 6 © 2009 SCILLC. All rights reserved.
Characteristics subject to change without notice
E1 E
A2
A1
e
b
D
c
A
TOP VIEW
SIDE VI EW END VI EW
L1
LL2
SYMBOL MIN NOM MAX
A1.00
A1 0.01 0.05 0.10
A2 0.80 0.87 0.90
b0.30 0.45
c 0.12 0.15 0.20
D 2.90 BSC
E 2.80 BSC
E1 1.60 BSC
e0.95TYP
L 0.30 0.40 0.50
L1 0.60 REF
L2 0.25 BSC
0º 8º
PACKAGE OUTLINE DRAWING
TSOT-23 5-Lead (TD) (1)
Notes:
(1) All dimensions in millimeters. Angles in degrees.
(2) Complies with JEDEC standard MO-193.
CAT102
© 2009 SCILLC. All rights reserved. 7 Doc. No. MD-4007 Rev. P
Characteristics subject to change without notice
EXAMPLE OF ORDERING INFORMATION 1
ORDERING PART NUMBER
CAT102TDI-G
Notes:
(1) All packages are RoHS-compliant (Lead-free, Halogen-free)
(2) The device used in the above example is a CAT102TDI-GT3 (TSOT-23, Industrial Temperature, NiPdAu, Tape & Reel, 3,000/Reel)
Prefix Device # Suffix
CAT 102 TD I - G T3
Company ID Package
TD: TSOT-23
Temperature Range
I = Industrial
(
-40°C to 85°C
)
Product Numbe
r
102
Tape & Reel
T: Tape & Reel
3: 3,000/Reel
Lead Finish
G: NiPdAu
(
PPF
)
CAT102
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any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer's technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer
purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and
distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated
with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
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PUBLICATION ORDERING INFORM ATION
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For additional information, please contact your local
Sales Representative
Doc. No. MD-4007 Rev. P 8 © 2009 SCILLC. All rights reserved.
Characteristics subject to change without notice
REVISION HISTORY
Date Rev. Description
29-Jan-07 M Added Ordering Information
16-Jun-07 N
Changed package from SOT-23 to TSOT-23
Updated Features
Updated Functional Diagram
Updated Electrical Characteristics
Updated Typical Performance Characteristics
Changed termination from SnPb to NiPdAu
Added MD- to document Number
19-Nov-08 O Change logo and fine print to ON Semiconductor
05-Feb-09 P Updated Electrical Characteristics Table
