Feature summary
■ Input voltage from 1.7 to 3.6V
■ Ultra low dropout voltage (130mV typ. at
300mA load)
■ Very low quiescent current (110µA typ. at no
load, 130µA max. at 300mA load; max 0.5µA in
OFF MODE)
■ Output voltage tolerance: +/- 1.0% @ 25°C, +/-
2.0% full temperature range
■ Guaranteed output current up to 300mA
■ Wide range of output voltage: 0.8V to 3.0V
■ Logic-controlled electronic shutdown
■ Compatible with ceramic capacitor C
■ Internal current and thermal limit
■ Temperature range: -40°C to 85°C
= 1µF
O
Description
The LD3980 provides up to 300mA, from 1.7V to
3.6V input voltage. It can deliver a guaranteed
300mA continuous load current with a low 100mV
dropout. It is stable with ceramic capacitor. The
LD3980
Low drop - Low supply voltage
Low ESR capacitor compatible
DFN6 (3x3)
ultra low drop-voltage, low quiescent current and
low noise makes it suitable for low power
applications and in battery powered systems.
High power supply rejection is maintained down
to low input voltage levels common to battery
operated circuits. Shutdown Logic Control
function is available this means that when the
device is used as local regulator, it is possible to
put a part of the board in standby, decreasing the
total power consumption. The device also
includes a constant current limiting and thermal
overload protection. Typical applications are in
mobile phone, personal digital assistant (PDAs),
cordless phone and similar battery powered
wireless systems, portable information
appliances..
Block diagram
December 2006 Rev. 1 1/16
www.st.com
16
LD3980
Contents
1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.2 Current limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.3 Thermal overload protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.4 Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.5 Output capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8 Order code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2/16
LD3980 Pin configuration
1 Pin configuration
Figure 1. Pin connections
Table 1. Pin description
Pin N° Symbol Name and function
1 OUT Output Voltage of the LDO
2, 3 NC Not connected
4 GND Common ground.
SHUTDOWN Input Voltage:
5 SHDN
6 IN Input Voltage of the LDO
Active-Low Shutdown input. A logic Low reduces supply current to below 1µA.
Connect to IN or logic high for normal operation
Table 2. Thermal data
Symbol Parameter Value Unit
R
thJA
Thermal resistance junction-ambient 55 °C/W
3/16
Maximum ratings LD3980
2 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
DC Input voltage -0.3 to 4.6 V
DC Output voltage -0.3 to VI +0.3 V
Shutdown input voltage -0.3 to VI +0.3 V
Reset output voltage -0.3 to VI +0.3 V
Output current Internally limited mA
Power dissipation Internally limited mW
Storage temperature range -65 to 150 °C
Operating junction temperature range -40 to 85 °C
V
V
SHDN
V
RESET
P
T
T
V
I
O
I
O
D
STG
OP
Note: Absolute Maximum Ratings are those values beyond which damage to the device may
occur. Functional operation under these condition is not implied.
4/16
LD3980 Typical application
3 Typical application
Figure 2. Application circuit
5/16
Electrical characteristics LD3980
4 Electrical characteristics
Table 4. Electrical characteristics (TJ = 25°C, VI = V
V
= VI, unless otherwise specified) (
SHDN
Note: 1
O(NOM)
+0.5V, CI = CO = 1µF, IO = 1mA,
)
Symbol Parameter Test conditions Min. Typ. Max. Unit
Operating input voltage 1.7 3.6 V
V
I
= 300mA -1.0 +1.0
I
O
TJ = -40° to 85°C -2.0 +2.0
= 300mA, VO ≥ 1.8V
I
O
)
= -40° to 85°C
T
J
V
= V
I
V
RIPPLE
V
IN
V
RIPPLE
+0.5V±V
O(NOM)
RIPPLE
= 0.1V, f = 1KHz, IO = 10mA
= V
O(NOM)
+0.5V±V
RIPPLE
= 0.1V, f=10KHz, IO = 10mA
130 150 mV
60
58
∆V
∆V
V
DROP
SVR
V
VO Accuracy
O
Line regulation VI = VO + 0.5V to 3.6V, IO = 1mA -0.15 0.01 +0.15 %/V
O
Load regulation IO = 1mA to 300mA 0.2 0.3 %/mA
O
Dropout voltage (
Output noise voltage 10Hz to 100KHz, IO = 10mA, 110.7 µV
e
N
Note 2
Supply voltage rejection
Figure 7.
(
)
IO=0mA 90
=0mA, TJ = -40° to 85°C 110
I
O
IO=0 to 300mA 105
I
=0 to 300mA, TJ = -40° to 85°C 130
O
VI input current 0.15 0.5
-5% 610 mA
O(NOM)
0.4
= 1.6V to 3.6V TJ = -40° to 85°C
V
I
I
I
O(PK)
V
SHDN
Quiescent current
I
Q
ON MODE: V
SHDN
=1.4V
Quiescent current
OFF MODE: V
Short circuit current RL=0 650 mA
SC
SHDN
=GND
Peak output current VO ≥ V
Shutdown input logic low
Shutdown input logic high 1.4
%
RMS/VO
dB
µA
V
I
SHDN
T
T
SHDN
C
Shutdown input current V
Turn on time
ON
Thermal shutdown
Output capacitor
O
Note: 1 For V
2 Dropout voltage is the input-to-output voltage difference at which the output voltage is
100mV below its nominal value. This specification does not apply for output voltages below
1.7V.
3 Turn-on time is time measured between the enable input just exceeding V
and the output voltage just reaching 95% of its nominal value
4 Typical thermal protection hysteresis is 15°C.
6/16
O(NOM)
SHDN
Note 3
Note 4
Capacitance 1 10 µF
ESR 10 5000 mΩ
< 1.2V, VI=1.7V
=GND or V
I
0.1 100 nA
120 µs
140 °C
High Value
SHDN
LD3980 Typical characteristics
5 Typical characteristics
Figure 3. Output voltage vs temperature Figure 4. Output voltage vs input voltage
Figure 5. Inhibit voltage vs temperature Figure 6. Dropout voltage vs temperature
Figure 7. S.V.R. vs frequency Figure 8. Stability value
VI=V
O(NOM)
+0.5V+V
, IO=10mA CI =CO= 1µF
RIPPLE
VI= from 1.76 to 3.6V, IO=from 1mA to 0.3A
7/16
Typical characteristics LD3980
Figure 9. Stability value Figure 10. Load transient
VI= from 1.76 to 3.6V, IO=from 1mA to 0.3A
Figure 11. Line transient
V
, IO=1mA No CI, CO= 1µF, T
INH=VI
RISE=TFALL
=1µs
V
, IO=10 to 300mA No CO,CI= 1µF, T
INH=VI
RISE=TFALL
=5µs
8/16
LD3980 Detailed description
6 Detailed description
The device is a low-dropout, low quiescent current linear regulator designed primarily for
battery-powered applications. It supplies a regulated output voltage for load currents up to
300mA. The LD3980 consists of a precision bandgap, error amplifier, output p-channel
MOS. The 0.7V bandgap reference is connected to the error amplifier. The error amplifier
compares this reference to the feedback voltage and amplifies the difference. The MOSFET
driver reads the error signal and applies the appropriate drive to the P-channel pass
transistor. If the feedback voltage is lower than reference voltage, the pass transistor is
pulled lower, allowing more current to pass and increasing the output voltage. If the
feedback voltage is higher than the reference voltage, the pass transistor gate is driven
higher, allowing less current to pass the output. The output voltage is feedback through an
internal resistor voltage connected to OUT. Additional blocks include an output current
limiter, a thermal sensor and shutdown logic.
6.1 Shutdown
Drive SHDN low to place the LD3980 in shutdown mode for DFN versions.
In shutdown mode, the pass transistor, control circuit, reference and all biases are turned
off, reducing the supply current to typically 0.5µA. Connecting SHDN to IN every block is in
normal operation.
6.2 Current limit
The device includes short-circuit protection. It includes a current limiter that controls the
pass transistor's gate voltage to limit the output current to about 600mA.
6.3 Thermal overload protection
The Thermal over load protection limits total power dissipation in the device. When the
junction temperature (T
shutdown logic, turning off the pass transistor and allowing the device to cool. The pass
transistor turns on again after the device's junction temperature typically cools by 15°C,
resulting in a pulsed output during continuous thermal overload conditions.
) exceeds +140°C, the thermal sensor sends a signal to the
J
6.4 Power dissipation
Maximum power dissipation of the LD3980 depends on the thermal resistance of the case
and circuit board, the temperature difference between the die junction and ambient air, and
the rate of air flow. The power dissipated by the device is:
P
= IO (VI - VO)
D
The maximum power dissipation is:
P
= (T
MAX
Where: T
JMAX
JMAX
- TA) / θ
= +150°C
JA
9/16
Detailed description LD3980
TA is the ambient temperature
θ
thermal resistance.
JA
The device's pins perform the dual function of providing an electrical connection as well as
channeling heat away from the die. Use wide circuit-board traces and large, solid copper
polygons to improve power dissipation. Using multiple vias to buried ground planes further
enhances thermal conductivity.
6.5 Output capacitance
The device is specifically designed to employ ceramic output capacitors as low as 1µF.
Ceramic capacitors below 10µF offer significant cost and space savings, along with high
frequency noise filtering. Higher values and other types of capacitor may be used, but their
equivalent series resistance should be maintained in the range of the table.
10/16
LD3980 Package mechanical data
7 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
11/16
Package mechanical data LD3980
DFN6 (3x3) MECHANICAL DATA
mm. mils
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 0.80 1.00 31.5 39.4
A1 0 0.05 0.0 2.0
A2 0.65 0.75 25.6 29.5
A3 0.20 7.9
b 0.33 0.43 13.0 16.9
D2.90 3.00 3.10 114.2 118.1 122.0
D2 1.92 2.12 75.6 83.5
E2.90 3.00 3.10 114.2 118.1 122.0
E2 1.11 1.31 43.7 51.6
e0.95 37.4
L 0.20 0.45 7.9 17.7
L1 0.24 9.4
L2 0.13 5.1
K0.20 7.9
12/16
7387339A
LD3980 Package mechanical data
Tape & Reel QFNxx/DFNxx (3x3) MECHANICAL DATA
mm. inch
DIM.
MIN. TYP MAX. MIN. TYP. MAX.
A 330 12.992
C 12.8 13.2 0.504 0.519
D 20.2 0.795
N 60 2.362
T 18.4 0.724
Ao 3.3 0.130
Bo 3.3 0.130
Ko 1.1 0.043
Po 4 0.157
P 8 0.315
13/16
Order code LD3980
8 Order code
Table 5. Order code
Part number Output voltage
LD3980PM08R 0.8 V
LD3980PM12R 1.2 V
LD3980PM13R 1.3 V
LD3980PM135R 1.35 V
LD3980PM15R 1.5 V
LD3980PM18R 1.8 V
LD3980PM30R 3.0 V
1. Other values of VO available on request
2. Available on request
(1)
(2)
(2)
(2)
(2)
14/16
LD3980 Revision history
9 Revision history
Table 6. Revision history
Date Revision Changes
05-Dec-2006 1 First release.
15/16
LD3980
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