The ILC7080/81 are 50 or 100mA low dropout (LDO) volt-
age regulators designed to provide a high performance
solution to low power systems.
The devices offer a typical combination of low dropout
and low quiescent current expected of CMOS parts,
while uniquely providing the low noise and high ripple
rejection characteristics usually only associated with
bipolar LDO regulators.
The devices have been optimized to meet the needs of
modern wireless communications design; Low noise, low
dropout, small size, high peak current, high noise immuni-
ty. The ILC7080/81 are designed to make use of low cost
ceramic capacitors while outperforming other devices that
require tantalum capacitors.
Features
• Ultra low 1mV dropout per 1mA load
• 1% output voltage accuracy
• Uses low ESR ceramic output capacitor to minimize
noise and output ripple
• Only 100µA ground current at 100mA load
• Ripple rejection up to 85dB at 1kHz, 60dB at 1MHz
• Less than 80µV
RMS
noise at BW = 100Hz to 100kHz
• Excellent line and load transient response
• Over current / over temperature protection
• Guaranteed up to 80/150mA output current
• Industry standard five lead SOT-23 package
• Fixed 2.85V, 3.0V, 3.3V, 3.6V, 4.7V, 5.0V and adjustable
output voltage options
• Metal mask option available for custom voltages between
2.5 to 10V
Applications
•
•
•
•
Cellular phones
Wireless communicators
PDAs / palmtops / organizers
Battery powered portable electronics
Typical Circuit
V
OUT
5
SOT23-5
4
ILC7080
ILC7081
C
NOISE
3
C
OUT
V
IN
1
Ordering Information (T
A
= -40°C to +85°C)
ILC7080AIM5-xx
50mA, fixed voltage
ILC7080AIM5-ADJ
50mA adjustable voltage
ILC7081AIM5-xx
100mA, fixed voltage
ILC7081AIM5-ADJ
100mA, adjustable voltage
Note:
Fixed voltage options are defined by 2-digit code as shown in the
package markings information section of the datasheet.
2
ON
OFF
Impala Linear Corporation
ILC7080/81 1.1
(408) 574-3939
www.impalalinear.com
Sept. 1998
1
50/100mA SOT-23 CMOS RF LDO™ Regulators
Pin Description ILC7081/81-xx
(fixed voltage version)
Pin
Number
1
2
3
4
Pin Name
V
IN
GND
ON/OFF
C
NOISE
Pin Description
Connect direct to supply
Ground pin. Local ground for C
NOISE
and C
OUT
.
By applying less than 0.4V to this pin the device will be turned off.
Optional noise bypass capacitor may be connected between this
pin and GND (pin 2). Do not connect C
NOISE
directly to the main
power ground plane.
Output Voltage. Connect C
OUT
between this pin and GND (pin 2)
5
V
OUT
Pin Description ILC7081/81-ADJ
(adjustable voltage version)
Pin
Number
1
2
3
4
5
Pin Name
V
IN
GND
ON/OFF
V
ADJ
V
OUT
Pin Description
Connect direct to supply
Ground pin. Local ground for C
NOISE
and C
OUT
.
By applying less than 0.4V to this pin the device will be turned off.
Voltage feedback pin to set the adjustable output voltage. Do not
connect a capacitor to this pin.
Output Voltage. Connect C
OUT
between this pin and GND (pin 2)
Pin Package Configurations
V
OUT
5
C
NOISE
SOT23-5
4
V
OUT
5
V
ADJ
SOT23-5
4
ILC7080-xx
ILC7081-xx
1
2
3
ILC7080-ADJ
ILC7081-ADJ
1
2
3
V
IN
GND
ON
OFF
V
IN
GND
ON
OFF
Impala Linear Corporation
ILC7080/81 1.1
(408) 574-3939
www.impalalinear.com
Sept. 1998
2
50/100mA SOT-23 CMOS RF LDO™ Regulators
Absolute Maximum Ratings (Note 1)
Parameter
Input voltage
On/Off Input voltage
Output Current
Output voltage
Package Power Dissipation
(SOT-23-5)
Maximum Junction Temp Range
Storage Temperature
Operating Ambient Temperature
Package Thermal Resistance
Symbol
V
IN
V
ON/OFF
I
OUT
V
OUT
P
D
T
J(max)
T
STG
T
A
θ
JA
Ratings
-0.3 to +13.5
-0.3 to V
IN
Short circuit protected
-0.3 to V
IN
+0.3
250
(Internally Limited)
-40~+150
-40~+125
-40 to +85
333
Units
V
mA
V
mW
°C
°C
°C
°C/W
Absolute Maximum Ratings (Note 1)
Unless otherwise specified, all limits are at T
A
= 25°C; V
IN
= V
OUT(NOM)
+ 1V, I
OUT
= 1mA, C
OUT
= 1µF, V
ON/OFF
= 2V.
Boldface
limits apply over the operating temperature range.
(Note 2)
Parameter
Input Voltage Range
Output voltage
Symbol
V
IN
V
OUT
Conditions
I
OUT
= 1mA
1mA < I
OUT
< 100mA
1mA < I
OUT
< 100mA
Feedback Voltage
(ADJ version)
Line Regulation
Dropout voltage
(Note 3)
V
ADJ
∆V
OUT
/
(V
OUT
*∆V
IN
)
V
OUT(NOM)
+ 1V < V
IN
< 12V
I
OUT
= 0mA
7080/81
V
IN
– V
OUT
I
OUT
= 50mA
I
OUT
= 100mA
7081 only
I
OUT
= 150mA
I
OUT
= 10mA
Min
2
-1
-1.5
-3.5
1.215
1.202
Typ
V
OUT(NOM)
1.240
0.007
0.1
10
50
100
150
Max
13
+1
1.5
+3.5
1.265
1.278
0.014
0.032
1
2
25
35
75
100
150
200
225
300
Units
V
%
V
%/V
mV
Impala Linear Corporation
ILC7080/81 1.1
(408) 574-3939
www.impalalinear.com
Sept. 1998
3
50/100mA SOT-23 CMOS RF LDO™ Regulators
Electrical Characteristics ILC7080/81AIM5 (cont.)
Unless otherwise specified, all limits are T
A
= 25°C; V
IN
= V
OUT(NOM)
+ 1V, I
OUT
= 1mA, C
OUT
= 1µF, V
ON/OFF
= 2V.
Boldface
limits apply over the operating temperature range.
(Note 2)
Parameter
Symbol
Conditions
I
OUT
= 0mA
7080/81
I
OUT
= 10mA
I
OUT
= 50mA
I
OUT
= 100mA
7081
only
I
OUT
= 150mA
Min
Typ
95
100
100
100
115
0.1
Ground Pin Current
I
GND
Shutdown (OFF) Current
ON/OFF Input Voltage
ON/OFF Pin Input Current
(Note 5)
Peak Output Current
(Note 4)
Output Noise Voltage
I
ON/OFF
V
ON/OFF
I
IN(ON/OFF)
I
OUT(PEAK)
e
N
∆V
OUT
/∆V
IN
∆V
OUT(line)
Ripple Rejection
Dynamic Line Regulation
Dynamic Load Regulation
∆V
OUT(load)
Short Circuit Current
I
SC
V
ON/OFF
= 0V
High = Regulator On
Low = Regulator Off
V
ON/OFF
= 0.6V, regulator OFF
V
ON/OFF
= 2V, regulator ON
V
OUT
> 0.95V
OUT(NOM)
,
tpw = 2ms
BW = 300Hz to 50kHz,
C
NOISE
= 0.01µF
C
OUT
= 4.7µF,
freq = 1kHz
I
OUT
= 100mA
freq = 10kHz
freq = 1MHz
V
IN
: V
OUT(NOM)
+ 1V to
V
OUT(NOM)
+ 2V,
tr/tf = 2µs; I
OUT
= 100mA
I
OUT
: 0 to 100mA;
d(I
OUT
)/dt = 100mA/µs
with C
OUT
= 0.47µF
with C
OUT
= 2.2µF
V
OUT
= 0V
2.0
0.3
1
500
80
85
70
60
4
Max
200
220
220
240
220
240
240
260
260
280
2
13
0.6
Units
µA
µA
V
µA
mA
µV
RMS
400
dB
mV
50
25
600
mV
mA
Note 1: Absolute maximum ratings indicate limits which when exceeded may result in damage to the component. Electrical specifications do not apply when operating the
device outside of its rated operating conditions.
Note 2: Specified Min/Max limits are production tested or guaranteed through correlation based on statistical control methods. Measurements are taken at constant junction
temperature as close to ambient as possible using low duty pulse testing.
Note 3: Dropout voltage is defined as the input to output differential voltage at which the output voltage drops 2% below the nominal value measured with a 1V differential.
Note 4: Guaranteed by design
Note 5: The device’s shutdown pin includes a 2MW internal pull down resistor connected to ground.
Impala Linear Corporation
ILC7080/81 1.1
(408) 574-3939
www.impalalinear.com
Sept. 1998
4
50/100mA SOT-23 CMOS RF LDO™ Regulators
Operation
The ILC7080/81 LDO design is based on an advanced cir-
cuit configuration for which patent protection has been
applied. Typically it is very difficult to drive a capacitive out-
put with an amplifier. The output capacitance produces a
pole in the feedback path, which upsets the carefully tai-
lored dominant pole of the internal amplifier. Traditionally
the pole of the output capacitor has been “eliminated” by
reducing the output impedance of the regulator such that
the pole of the output capacitor is moved well beyond the
gain bandwidth product of the regulator. In practice, this is
difficult to do and still maintain high frequency operation.
Typically the output impedance of the regulator is not sim-
ply resistive, such that the reactive output impedance inter-
acts with the reactive impedance of the load resistance and
capacitance. In addition, it is necessary to place the domi-
nant pole of the circuit at a sufficiently low frequency such
that the gain of the regulator has fallen below unity before
any of the complex interactions between the output and the
load occur. The ILC7080/81 does not try to eliminate the
output pole, but incorporates it into the stability scheme.
The load and output capacitor forms a pole, which rolls off
the gain of the regulator below unity. In order to do this the
output impedance of the regulator must be high, looking like
a current source. The output stage of the regulator
becomes a transconductance amplifier, which converts a
voltage to a current with a substantial output impedance.
The circuit which drives the transconductance amplifier is
the error amplifier, which compares the regulator output to
the band gap reference and produces an error voltage as
the input to the transconductance amplifier. The error ampli-
fier has a dominant pole at low frequency and a “zero”
which cancels out the effects of the pole. The zero allows
the regulator to have gain out to the frequency where the
output pole continues to reduce the gain to unity. The con-
figuration of the poles and zero are shown in figure 1.
Instead of powering the critical circuits from the unregulat-
ed input voltage, the CMOS RF LDO powers the internal
circuits such as the bandgap, the error amplifier and most
of the transconductance amplifier from the boot strapped
regulated output voltage of the regulator. This technique
offers extremely high ripple rejection and excellent line tran-
sient response.
A block diagram of the regulator circuit used in the
ILC7080/81 is shown in figure 2, which shows the input-to-
output isolation and the cascaded sequence of amplifiers
that implement the pole-zero scheme outlined above.
The ILC7080/81 were designed in a CMOS process with
some minor additions, which allow the circuit to be used at
input voltages up to 13V. The resulting circuit exceeds the
frequency response of traditional bipolar circuits. The
ILC7080/81 is very tolerant of output load conditions with
the inclusion of both short circuit and thermal overload pro-
tection. The device has a very low dropout voltage, typical-
ly a linear response of 1mV per milliamp of load current,
and none of the quasi-saturation characteristics of a bipolar
output device. All the good features of the frequency
response and regulation are valid right to the point where
the regulator goes out of regulation in a 4mV transition
region. Because there is no base drive, the regulator is
capable of providing high current surges while remaining in
regulation. This is shown in the high peak current of 500mA
which allows for the ILC7080/81 to be used in systems that
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