CAT6218
300mA CMOS LDO Regulator
FEATURES
Guaranteed 300mA output current
Low dropout voltage of 180mV typical at 300mA
Stable with 1μF ceramic output capacitor
External 10nF bypass capacitor for low noise
Quick-start feature
No-load ground current of 55μA typical
Full-load ground current of 80μA typical
±1.0% initial accuracy (V
OUT
≥
2.0V)
±2.0% accuracy over temperature (V
OUT
≥
2.0V)
“Zero” current shutdown mode
Fold-back current limit and under-voltage
lockout
Thermal protection
Thin SOT23-5 package
DESCRIPTION
The CAT6218 is a 300mA CMOS low dropout
regulator that provides fast response time during load
current and line voltage changes.
The quick-start feature allows the use of an external
bypass capacitor to reduce the overall output noise
without affecting the turn-on time of just 150μs.
With zero shutdown current and low ground current of
55μA typical, the CAT6218 is ideal for battery-
operated devices with supply voltages from 2.3V to
5.5V. An internal under voltage lockout circuit disables
the output at supply voltages under 2.1V typical.
The CAT6218 offers 1% initial accuracy and low
dropout voltage, 180mV typical at 300mA. Stable
operation is provided with a small value ceramic
capacitor, reducing required board space and compo–
nent cost.
Other features include fold-back current current limit
and thermal protection.
The device is available in the low profile (1mm max
height) 5-lead thin SOT23 package.
APPLICATIONS
Cellular phones
Battery-powered devices
Consumer Electronics
For Ordering Information details, see page 9.
PIN CONFIGURATION
TSOT-23 5-Lead
(1mm height)
VIN
1
GND
2
EN
3
Top View
TYPICAL APPLICATION CIRCUIT
5
VOUT
V
IN
2.3V
to 5.5V
OFF ON
C
IN
1µF
VIN
VOUT
V
OUT
C
OUT
1µF
CAT6218
EN
GND
BYP
4
BYP
C
BYP
(Optional)
10nF
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-10010 Rev. C
CAT6218
PIN DESCRIPTIONS
Pin # Name Function
1
VIN Supply voltage input.
2
GND Ground reference.
Enable input (active high); a 2.5MΩ
3
EN
pull-down resistor is provided.
Optional bypass capacitor connection
4
BYP for noise reduction and PSRR
enhancing.
5 VOUT LDO Output Voltage.
BLOCK DIAGRAM
VIN
V
IN
EN
LDO
VOUT
V
OUT
BYP
Reference
Shutdown
Switch
GND
Figure 2. CAT6218 Functional Block Diagram
PIN FUNCTION
VIN
is the supply pin for the LDO. A small 1μF
ceramic bypass capacitor is required between the V
IN
pin and ground near the device. When using longer
connections to the power supply, C
IN
value can be
increased without limit. The operating input voltage
range is from 2.3V to 5.5V.
EN
is the enable control logic (active high) for the regu-
lator output. It has a 2.5MΩ pull-down resistor, which
assures that if EN pin is left open, the circuit is disabled.
VOUT
is the LDO regulator output. A small 1μF cera-
mic bypass capacitor is required between the V
OUT
pin
and ground for stability. For better transient response,
its value can be increased to 4.7μF.
The capacitor should be located near the device. ESR
domain is 5mΩ to 500mΩ. V
OUT
can deliver a maxi-
mum guaranteed current of 300mA. For input-to-
output voltages higher than 1V, a continuous 300mA
output current might turn-on the thermal protection. A
250Ω internal shutdown switch discharges the output
capacitor in the no-load condition.
GND
is the ground reference for the LDO. The pin
must be connected to the ground plane on the PCB.
BYP
is the reference bypass pin. An optional 0.01μF
capacitor can be connected between BYP pin and
GND to reduce the output noise and enhance the
PSRR at high frequency.
ABSOLUTE MAXIMUM RATINGS
(1)
Parameter
V
IN
V
EN
, V
OUT
Junction Temperature, T
J
Power Dissipation, P
D
Storage Temperature Range, T
S
Lead Temperature (soldering, 5 sec.)
ESD Rating (Human Body Model)
Rating
0 to 6.5
-0.3 to V
IN
+ 0.3
+150
Internally Limited
(2)
-65 to +150
260
3
Unit
V
V
°C
mW
°C
°C
kV
RECOMMENDED OPERATING CONDITIONS
(3)
Parameter
V
IN
V
EN
Junction Temperature Range, T
J
Package Thermal Resistance (SOT23-5),
θ
JA
Range
2.3 to 5.5
0 to V
IN
-40 to +125
235
Unit
V
V
°C
°C/W
Typical application circuit with external components is shown on page 1.
Notes:
(1) Exceeding maximum rating may damage the device
(2) The maximum allowable power dissipation at any T
A
(ambient temperature) is P
Dmax
= (T
Jmax
– T
A
)/θ
JA
. Exceeding the maximum allowable
power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
(3) The device is not guaranteed to work outside its operating rating.
Doc. No. MD-10010 Rev. C
2
©
Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT6218
ELECTRICAL OPERATING CHARACTERISTICS
(1)
V
IN
= V
OUT
+ 1.0V, V
EN
= High, I
OUT
= 100μA, C
IN
= C
OUT
= 1µF, ambient temperature of 25ºC (over recommended
operating conditions unless specified otherwise).
Bold numbers
apply for the entire junction temperature range.
Symbol Parameter
V
OUT-ACC
Output Voltage Accuracy
TC
OUT
V
R-LINE
V
R-LOAD
V
DROP
Output Voltage Temp. Coefficient
Line Regulation
Load Regulation
Dropout Voltage
(2)
V
IN
= V
OUT
+ 1.0V to 5.5V
I
OUT
= 100μA to 300 mA
I
OUT
= 300mA
I
OUT
= 0μA
I
OUT
= 300mA
I
GND-SD
PSRR
I
SC
T
ON
e
N
R
EN
V
UVLO
ESR
Shutdown Ground Current
Power Supply Rejection Ratio
Output short circuit current limit
Turn-On Time
Output Noise Voltage
(3)
Enable pull-down resistor
Under-voltage lock out (UVLO)
threshold
C
OUT
equivalent series resistance
V
IN
= 2.3 to 5.5V
V
IN
= 2.3 to 5.5V, 0ºC to
+125ºC junction temperature
V
IN
= 2.3 to 5.5V
V
EN
= 0.4V
V
EN
= V
IN
5
1.8
1.6
0.4
0.15
1.5
160
10
1
4
V
V
μA
V
EN
< 0.4V
f = 1kHz, C
BYP
= 10nF
f = 20kHz, C
BYP
= 10nF
V
OUT
= 0V
C
BYP
= 10nF
BW = 10Hz to 100kHz
64
54
180
150
45
250
2.5
2.1
500
-0.2
-0.4
0.7
180
55
80
1
2
μA
dB
mA
μs
μVrms
Ω
MΩ
V
mΩ
Conditions
Initial accuracy for V
OUT
≥
2.0V
(4)
Min
-1.0
-2.0
40
±0.1
+0.2
+0.4
1.2
1.5
250
300
75
90
μA
Typ
Max
+1.0
+2.0
Unit
%
ppm/ºC
%/V
%
mV
I
GND
Ground Current
R
OUT-SH
Shutdown Switch Resistance
Enable Input
V
HI
V
LO
I
EN
Logic High Level
Logic Low Level
Enable Input Current
Thermal Protection
T
SD
T
HYS
Thermal Shutdown
Thermal Hysteresis
ºC
ºC
Notes:
(1 Specification for 2.85V output version unless specified otherwise.
(2) Dropout voltage is defined as the input-to-output differential at which the output voltage drops 2% below its nominal value measured at
1V differential. During test, the input voltage stays always above the minimum 2.3V.
(3) Specification for 1.8V output version.
(4) For V
OUT
< 2.0V, the initial accuracy is
±2%
and across temperature
±3%.
©
Catalyst Semiconductor, Inc.
3
Doc. No. MD-10010 Rev. C
Characteristics subject to change without notice
CAT6218
TYPICAL CHARACTERISTICS
(shown for 2.85V output version)
V
IN
= 3.85V, I
OUT
= 100μA, C
IN
= C
OUT
= 1μF, C
BYP
= 10nF, T
A
= 25°C unless otherwise specified.
Dropout Characteristics
3.0
100μA
Line Regulation
2.87
OUTPUT VOLTAGE [V]
2.86
2.85
2.84
2.83
2.82
OUTPUT VOLTAGE [V]
2.5
2.0
300mA
1.5
1.0
0.5
0.0
0.0
1.0
2.0 3.0 4.0 5.0
INPUT VOLTAGE [V]
6.0
2.5
3.0 3.5 4.0 4.5 5.0
INPUT VOLTAGE [V]
5.5
Load Regulation
2.95
OUTPUT VOLTAGE [V]
Output Voltage vs. Temperature
2.87
OUTPUT VOLTAGE [V]
2.86
2.85
2.84
2.83
2.82
-40
-10 20 50 80 110 140
TEMPERATURE [°C]
2.90
2.85
2.80
2.75
0
50 100 150 200 250 300
OUTPUT LOAD CURRENT [mA]
Ground Current vs. Load Current
100
GROUND CURRENT [μA]
90
80
70
60
50
0
25
50 75 100 125 150
OUTPUT LOAD CURRENT [mA]
Ground Current vs. Temperature
65
GROUND CURRENT [μA]
60
55
50
45
-40
-10
20
50
80 110 140
TEMPERATURE [°C]
Doc. No. MD-10010 Rev. C
4
©
Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT6218
TYPICAL CHARACTERISTICS
(shown for 2.85V output option)
V
IN
= 3.85V, I
OUT
= 100μA, C
IN
= C
OUT
= 1μF, C
BYP
= 10nF, T
A
= 25°C unless otherwise specified.
Output Voltage vs. Load Current
3.0
GROUND CURRENT [μA]
70
60
50
40
30
20
10
0
Ground Current vs. Input Voltage
OUTPUT VOLTAGE [V]
2.5
2.0
1.5
1.0
0.5
0.0
0
100 200 300 400 500 600 700
OUTPUT LOAD CURRENT [mA]
0.0
1.0
2.0 3.0 4.0 5.0
INPUT VOLTAGE [V]
6.0
Dropout vs. Temperature (300mA Load)
350
DROPOUT VOLTAGE [mV]
Dropout vs. Load Current
300
DROPOUT VOLTAGE [mV]
250
200
150
100
50
0
0
50 100 150 200 250 300
OUTPUT LOAD CURRENT [mA]
300
250
200
150
100
-40
-10 20
50 80 110 140
TEMPERATURE [°C]
Enable Threshold vs. Input Voltage
1.6
ENABLE THRESHOLD [V]
PSRR vs. Frequency (10mA Load)
80
70
C
BY P
= 10nF
1.2
PSRR [dB]
60
50
40
30
20
10
C
BY P
= 0
0.8
0.4
0.0
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE [V]
©
Catalyst Semiconductor, Inc.
5
0
0.01
0.1
1
10
FREQUENCY [kHz]
100
Doc. No. MD-10010 Rev. C
Characteristics subject to change without notice
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