ADP3309ART-2.85R7 ,anyCAP® 100 mA Low Dropout Linear RegulatorSPECIFICATIONSParameter Symbol Conditions Min Typ Max UnitOUTPUT VOLTAGE ACCURACY V V = V + 0.3 V t ..
ADP3309ART-2.85-R7 ,anyCAP® 100 mA Low Dropout Linear Regulatorapplications.Figure 1. Typical Application CircuitThe ADP3308 achieves ±1.2% accuracy at room tempe ..
ADP3309ART-2.85-RL ,anyCAP® 100 mA Low Dropout Linear Regulator®anyCAP 50 mAaLow Dropout Linear RegulatorADP3308
ADP3309ART-3.3 ,anyCAP⑩ 100 mA Low Dropout Linear RegulatorSPECIFICATIONSParameter Symbol Conditions Min Typ Max UnitsOUTPUT VOLTAGE ACCURACY V V = V + 0.3 V ..
ADP3309ART-3.3-RL ,anyCAP® 100 mA Low Dropout Linear RegulatorSpecifications subject to change without notice.–2– REV. BADP3308ABSOLUTE MAXIMUM RATINGS* PIN FUNC ..
ADP3309ART-3.3-RL7 ,anyCAP® 100 mA Low Dropout Linear RegulatorGENERAL DESCRIPTIONERR/NC 4The ADP3308 is a member of the ADP330x family of precisionADP3308-3.3low ..
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ADP3309ART-2.5-RL7-ADP3309ART-2.7-RL-ADP3309ART-2.7-RL7-ADP3309ART-2.85R7-ADP3309ART-2.85-R7-ADP3309ART-2.85-RL-ADP3309ART-3.3-RL-ADP3309ART-3.3-RL7-ADP3309ART-3-REEL7
anyCAP® 100 mA Low Dropout Linear Regulator
REV.B
anyCAP® 50 mA
Low Dropout Linear Regulator
FUNCTIONAL BLOCK DIAGRAM
FEATURES�1.2% Accuracy Over Line and Load Regulations
@ 25�C
Ultralow Dropout Voltage: 80 mV Typical @ 50 mA
Requires Only CO = 0.47 �F for Stability
anyCAP = Stable with All Types of Capacitors
(Including MLCC)
Current and Thermal Limiting
Low Noise
Low Shutdown Current: 1 �A
2.8 V to 12 V Supply Range
–20�C to +85�C Ambient Temperature Range
Several Fixed Voltage Options
Ultrasmall SOT-23-5 Package
Excellent Line and Load Regulations
APPLICATIONS
Cellular Telephones
Notebook, Palmtop Computers
Battery Powered Systems
PCMCIA Regulator
Bar Code Scanners
Camcorders, Cameras
GENERAL DESCRIPTIONThe ADP3308 is a member of the ADP330x family of precision
low dropout anyCAP voltage regulators. It is pin-for-pin and
functionally compatible with National’s LP2980, but offers
performance advantages. The ADP3308 stands out from the
conventional LDOs with a novel architecture and an enhanced
process. Its patented design requires only a 0.47 µF output
capacitor for stability. This device is stable with any type of
capacitor regardless of its ESR (Equivalent Serial Resistance)
value, including ceramic types for space restricted applications.
The ADP3308 achieves ±1.2% accuracy at room temperature
and ±2.2% overall accuracy over temperature, line and load
regulations. The dropout voltage of the ADP3308 is only 80mV
(typical) at 50 mA. This device also includes a current limit and
a shutdown feature. In shutdown mode, the ground current is
reduced to ~1 µA.
The ADP3308 operates with a wide input voltage range from
2.8 V to 12 V and delivers a load current in excess of 100 mA.
The ADP3308 anyCAP LDO offers a wide range of output
voltages. For 100 mA version, refer to the ADP3309 data sheet.
anyCAP is a registered trademark of Analog Devices, Inc.
Figure 1.Typical Application Circuit
ADP3308-xx–SPECIFICATIONS
(@ TA = –20�C to +85�C, VIN = 7 V, CIN = 0.47 �F, COUT = 0.47 �F, unless
otherwise noted.)1 The following specifications apply to all voltage options.NOTESAmbient temperature of 85°C corresponds to a junction temperature of 125°C under typical full load test conditions.
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS*Input Supply Voltage . . . . . . . . . . . . . . . . . . . –0.3 V to +16 V
Shutdown Input Voltage . . . . . . . . . . . . . . . . –0.3 V to +16 V
Power Dissipation . . . . . . . . . . . . . . . . . . . Internally Limited
Operating Ambient Temperature Range . . . –55°C to +125°C
Operating Junction Temperature Range . . . –55°C to +125°C
θJA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165°C/W
θJC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92°C/W
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering 10 sec) . . . . . . . . 300°C
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
*This is a stress rating only; operation beyond these limits can cause the device to
be permanently damaged.
ORDERING GUIDE*SOT = Surface Mount.
Contact the factory for the availability of other output voltage options.
Other Member of anyCAP Family1NOTESSee individual data sheet for detailed ordering information.SOT = Surface Mount.
PIN FUNCTION DESCRIPTIONS
PIN CONFIGURATION
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the ADP3308 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
ADP3308
–Typical Performance Characteristics
INPUT VOLTAGE – Volts
OUTPUT VOLTAGE – Volts
3.295TPC 1.Line Regulation: Output
Voltage vs. Supply Voltage
TPC 4.Quiescent Current vs. Load
Current
TPC 7.Dropout Voltage vs. Output
Current
TPC 2.Output Voltage vs. Load
Current
TPC 5.Output Voltage Variation %
vs. Temperature
INPUT VOLTAGE – Volts03043211
INPUT/OUTPUT VOLTAGE
VoltsTPC 8.Power-Up/Power-Down
INPUT VOLTAGE – Volts
GROUND CURRENT
160TPC 3.Quiescent Current vs.
Supply Voltage
TPC 6.Quiescent Current vs.
Temperature
TPC 9.Power-Up Overshoot
TPC 10.Line Transient Response
TPC 13.Load Transient
TIME – �s10020406080
VoltsTPC 16.Turn Off
TIME – �s
Volts
3.290TPC 11.Line Transient Response
TPC 14.Short Circuit Current
FREQUENCY – Hz
RIPPLE REJECTION
dB
–10010010M1k10k100k1M
–40TPC 17.Power Supply Ripple
Rejection
TPC 12.Load Transient
TPC 15.Turn On
TPC 18.Output Noise Density
ADP3308
THEORY OF OPERATIONThe new anyCAP LDO ADP3308 uses a single control loop for
regulation and reference functions. The output voltage is sensed
by a resistive voltage divider consisting of R1 and R2, which is
varied to provide the available output voltage option. Feedback
is taken from this network by way of a series diode (D1) and a
second resistor divider (R3 and R4) to the input of an amplifier.
Figure 2.Functional Block Diagram
A very high gain error amplifier is used to control this loop.
The amplifier is constructed in such a way that at equilibrium it
produces a large, temperature proportional input “offset voltage”
that is repeatable and very well controlled. The temperature
proportional offset voltage is combined with the complementary
diode voltage to form a “virtual bandgap” voltage, implicit in
the network, although it never appears explicitly in the circuit.
Ultimately, this patented design makes it possible to control the
loop with only one amplifier. This technique also improves the
noise characteristics of the amplifier by providing more flexibil-
ity on the tradeoff of noise sources that leads to a low noise design.
The R1, R2 divider is chosen in the same ratio as the bandgap
voltage to the output voltage. Although the R1, R2 resistor
divider is loaded by the diode D1 and a second divider consisting
of R3 and R4, the values can be chosen to produce a tempera-
ture stable output. This unique arrangement specifically corrects
for the loading of the divider so that the error resulting from
base current loading in conventional circuits is avoided.
The patented amplifier controls a new and unique noninverting
driver that drives the pass transistor, Q1. The use of this special
noninverting driver enables the frequency compensation to
include the load capacitor in a pole splitting arrangement to
achieve reduced sensitivity to the value, type and ESR of the
load capacitance.
Most LDOs place very strict requirements on the range of ESR
values for the output capacitor because they are difficult to
stabilize due to the uncertainty of load capacitance and resis-
tance. Moreover, the ESR value required to keep conventional
LDOs stable, changes, depending on load and temperature.
These ESR limitations make designing with LDOs more diffi-
cult because of their unclear specifications and extreme varia-
tions over temperature.
This is no longer true with the ADP3308 anyCAP LDO. It can
be used with virtually any capacitor, with no constraint on the
minimum ESR. This innovative design allows the circuit to be
stable with just a small 0.47 µF capacitor on the output. Addi-
Additional features of the circuit include current limit and ther-
mal shutdown. Compared to the standard solutions that give
warning after the output has lost regulation, the ADP3308 pro-
vides improved system performance by enabling the ERR pin to
give warning before the device loses regulation.
As the chip’s temperature rises above 165°C, the circuit activates
a soft thermal shutdown, indicated by a signal low on the ERR
pin, to reduce the current to a safe level.
APPLICATION INFORMATION
Capacitor Selection: anyCAPOutput Capacitors: as with any micropower device, output
transient response is a function of the output capacitance. The
ADP3308 is stable with a wide range of capacitor values, types
and ESR (anyCAP). A capacitor as low as 0.47 µF is all that is
needed for stability. However, larger capacitors can be used if
high output current surges are anticipated. The ADP3308 is
stable with extremely low ESR capacitors (ESR ≈ 0), such as
multilayer ceramic capacitors (MLCC) or OSCON.
Input Bypass Capacitor: an input bypass capacitor is not required.
However, for applications where the input source is high imped-
ance or far from the input pin, a bypass capacitor is recommended.
Connecting a 0.47 µF capacitor from the input pin (Pin 1) to
ground reduces the circuit’s sensitivity to PC board layout. If a
bigger output capacitor is used, the input capacitor must be 1µF
minimum.
Thermal Overload ProtectionThe ADP3308 is protected against damage due to excessive
power dissipation by its thermal overload protection circuit
which limits the die temperature to a maximum of 165°C.
Under extreme conditions (i.e., high ambient temperature and
power dissipation) where die temperature starts to rise above
165°C, the output current is reduced until the die temperature
has dropped to a safe level. The output current is restored when
the die temperature is reduced.
Current and thermal limit protections are intended to protect
the device against accidental overload conditions. For normal
operation, device power dissipation should be externally limited
so that junction temperatures will not exceed 125°C.
Calculating Junction TemperatureDevice power dissipation is calculated as follows:
PD = (VIN – VOUT) ILOAD + (VIN) IGND
Where ILOAD and IGND are load current and ground current, VIN
and VOUT are input and output voltages respectively.
Assuming ILOAD = 50 mA, IGND = 2 mA, VIN = 5.5 V and
VOUT = 2.7 V, device power dissipation is:
PD = (5.5 – 2.7) 50 mA + 5.5 × 2 mA = 151 mW
∆T = TJ – TA = PD × θJA = 151 × 165 = 24.9°C
With a maximum junction temperature of 125°C, this yields a
maximum ambient temperature of ~100°C.
Printed Circuit Board Layout ConsiderationSurface mount components rely on the conductive traces or
pads to transfer heat away from the device. Appropriate PC
board layout techniques should be used to remove heat from the
