Catalyst CAT102 Precision, adjustable shunt regulator Datasheet

CAT102
Precision, Adjustable Shunt Regulator
(600mV Reference)
FEATURES
DESCRIPTION
„ Low voltage reference: 600mV
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
600mV. Over a junction temperature from -40°C to
105°C the reference voltage is within 8mV of the
nominal 600mV. In addition, the error amplifier output
and the supply voltage pin are on separate pins.
„ Low temperature coefficient reference: 25ppm
„ Accurate 600mV reference voltage:
+6mV at TJ = 25ºC
„ High PSRR: 45dB at 300kHz
„ High line rejection: ±1mV (VCC from 2.2V to 18V)
„ Low supply current: 300µA
Power supply rejection is a high 45dB at 300kHz. The
output, OUT, can sink 20mA at a maximum saturation
voltage of 250mV.
„ Open collector output
„ Directly drives optocouplers
„ Compact 5-lead SOT23 package
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.
„ Industrial temperature range: -40ºC to 85ºC
APPLICATION
„ SMPS control loop
„ Low temperature coefficient voltage reference
„ Power management
For Ordering Information details, see page 8.
„ Replaces zener diodes
„ Isolated DC-to-DC converters
„ Network, telecom and cellular base station
„ Adjustable voltage reference
PIN CONFIGURATION
FUNCTIONAL DIAGRAM
IN
FB
1
5
Error
Amplifier
SOT-23 5L
Top View
OUT
3
+
VREF
600mV
–
+
–
1 1
GND
2 2
OUT
4 3
5
8 IN
4
5 NC
PIN DESCRIPTION
Pin Name
2
GND
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
FB
FB
1
Function
Inverting input to error amplifier
GND
Ground
OUT
Output of error amplifier. Source & sink
current capability is 20mA.
NC
No connection
IN
Positive supply
Doc. No. 4007 Rev. M
CAT102
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 (10s)
150
ºC
Lead Soldering Temperature (10s)
260
ºC
-65 to +150
ºC
Storage Temperature Range
ELECTRICAL CHARACTERISTICS
Electrical characteristics are guaranteed over the full operating temperature range of -40°C to +85°C with a
junction temperature from -40°C to +105°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 = 3V, FB = OUT, IOUT = 1mA.
Symbol
Parameter
VIN
Supply Voltage Range
IIN
Quiescent Supply Current
VFB
FB Threshold Reference Voltage
TCREF
IFB
PSRR
Conditions
Min
Typ
Max
Units
18
V
0.3
0.5
mA
600
606
2.2
VOUT =1V
TJ = 25˚ C
594
-40ºC <TJ<105ºC
592
Line Regulation
VIN = 2.2V to VIN =18V
Load Regulation
Reference Temperature Deviation
608
mV
0.5
1
mV
IOUT = 1mA to 10mA
4
8
mV
-40ºC < TJ < 105ºC
25
50
ppm/ºC
500
nA
FB Input Current
-500
Reference Power Supply Rejection
Frequency = 300kHz
35
45
dB
AV
Error Amplifier Open Loop Gain
IOUT = 2mA, VOUT = 1V
60
80
dB
BW
Unity Gain Frequency
IOUT = 2mA, VOUT = 1V
1
2
MHz
VOUT
Output Saturation voltage
IOUT = 20mA, VFB = HIGH
100
TRANSC
Output Transconductance
IOUT = 1mA to 20mA
2.5
ILEAK
Output Leakage Current
VOUT = 16V, VFB = 0
200
IOUT(MAX)
Maximum Output Current
VOUT = 0.3V
20
250
mV
mA/mV
400
nA
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 (ΘJA) of SOT-23 5-lead: 255°C/W
Doc. No. 4007 Rev. M
2
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT102
TYPICAL PERFORMANCE CHARACTERISTICS
Line Regulation (at 1mA)
Load Regulation
6
Output Voltage Change (mV)
Output Voltage Change (mV)
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
2.2
6
10
14
5
4
3
2
1
0
18
1
5
Supply Voltage (V)
15
20
Power-Supply Rejection Ratio vs. Frequency
Supply Current vs. Load Current
300
-50
280
-55
260
-60
240
-65
PSRR (dB)
Supply Current (µA)
10
Load Current (mA)
220
200
180
-70
-75
-80
160
-85
140
-90
-95
120
-100
0.1
100
0
5
10
15
L o a d C u r re n t (m A )
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
20
1
10
100
1000
10000 100000
F re q u e n c y (H z )
3
Doc. No. 4007 Rev. M
CAT102
TYPICAL PERFORMANCE CHARACTERISTICS
FB Bias Current vs. Temperature (V CC = 2.5V)
Reference Voltage
630
-10
Reference Voltage (V)
FB Bias Current (nA)
0
-20
-30
-40
-50
-60
620
10mA
610
600
590
580
-70
-40
0
40
80
570
-40
120
Junction Temperature (ºC)
0
40
80
120
Junction Temperature (ºC)
Gain vs. Frequency
110
Gain (dB)
90
70
50
30
10
-10
0.01
0.1
1
10
100 1000 10000
Frequency (kHz)
Doc. No. 4007 Rev. M
4
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT102
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 20mA with
VOUT at 0.3V. The wide input supply range allows the
device to operate from 2.2V to 18V. 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 600mV, the OUT pin
sinks up to 20mA.
The current limit can be adjusted by using a resistor R3
connected between the IN and OUT pins. For example,
a 3.3V supply VIN is associated with R3 = 135Ω, and a
10V supply works best with R3 = 470Ω. The CAT102
shunt regulator is limited to low-current applications with
the OUT pin capable of sinking up to 20mA max.
Figure 1 shows the CAT102 configured as a shunt
regulator. To generate an output voltage of 0.6V, the
FB pin has to be directly connected to the OUT pin.
A 1.0µF capacitor from OUT to GND is recommended when the output voltage is 0.6V. A resistordivider connected from OUT to GND is used to
produce a higher output voltage as set by the
following equation:
VOUT = (1 + R1/R2) x 0.6V
Figure 1. Application circuits for 0.6V output and 1.2V output voltages
R3
VIN
VOUT
3.3V
0.6V/20mA
5
OUT
IN
3
C2
C1
0.1µF
CAT102
2
GND
FB
1µF
1
R3
VIN
VOUT = (1 + R1/R2) x 0.6V
3.3V
1.2V/20mA
5
OUT
IN
3
C1
0.1µF
CAT102
2
GND
FB
1
R1
C2
10kΩ
1µF
R2
10kΩ
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. 4007 Rev. M
CAT102
TYPICAL APPLICATION
VIN
VOUT
Regulator
with
Isolation
1V regulated
output
Opto-isolator
VCC > 2.2V
R3
100Ω
5
OUT
IN
3
C1
0.1µF
R4
100kΩ
R1
22kΩ
C2
CAT102
2
GND
FB
1
1µF
R2
33kΩ
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 2.2V.
Doc. No. 4007 Rev. M
6
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT102
PACKAGE OUTLINES
SOT-23 5 LEAD
SYMBOL
MIN
NOM
1.15
A
1.00
A1
0.05
A2
1.00
b
0.35
C
1.10
1.20
0.50
D
2.80
2.90
3.00
E
2.60
2.80
3.00
E1
1.50
1.60
1.70
L
0.95 TYP
0.35
0.45
L1
0.60 REF
L2
0.20 BSC
θ
SIDE VIEW
1.30
0.15
0.127
e
TOP VIEW
MAX
0°
0.55
8°
θ1
10°
θ2
10°
END VIEW
For current Tape and Reel information, download the PDF file from:
http://www.catsemi.com/documents/tapeandreel.pdf.
Notes:
(1) All dimensions in millimeters. Angles in degrees.
(2) Complies with ANSI Y14.5M.
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
7
Doc. No. 4007 Rev. M
CAT102
EXAMPLE OF ORDERING INFORMATION
Prefix
Device # Suffix
CAT
102
Company ID
TB
I
-
Package
TB: SOT-23
Product Number
102
Temperature Range
I = Industrial (-40°C to 85°C)
T3
Tape & Reel
T: Tape & Reel
3: 3000/Reel
10: 10000/Reel
Notes:
(1)
(2)
All packages are RoHS-compliant (Lead-free, Halogen-free)
The device used in the above example is a CAT102TBI-T3 (SOT-23, Industrial Temperature, Matte-Tin, Tape & Reel)
ORDERING PART NUMBER
CAT102TBI
Doc. No. 4007 Rev. M
8
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
REVISION HISTORY
Date
Rev.
01/29/2007
M
Reason
Added Ordering Information
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Corporate Headquarters
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Santa Clara, CA 95054
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Document No: 4007
Revision:
M
Issue date:
01/29/07
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