LP3987
300mA,Ultra-LowNoise
Ultra-fast CMOS LDO Regrlator
General Description
The LP3987 is designed for portable RF and
wireless applications with demanding performance
and space requirements. The LP3987 performance
is optimized for battery-powered systems to deliver
ultra low noise and low quiescent current. A noise
bypass pin is available for further reduction of
output noise. Regulator ground current increases
only slightly in dropout, further prolonging the
battery life. The LP3987 also works with low-ESR
ceramic capacitors, reducing the amount of board
space necessary for power applications, critical in
hand-held
wireless devices. The LP3987 consumes
less than 0.01µA in shutdown mode and has fast
turn-on time less than 50µs. The other features
include ultra low dropout voltage, high output
accuracy, current limiting protection, and high
ripple rejection ratio. Available in the 5-lead of
SOT-23 packages.
Features
Ultra-Low-Noise for RF Application
2.5V- 6V Input Voltage Range
Low Dropout : 220mV @ 300mA
High PSSR:-80dB at 1KHz
< 0.01 A Standby Current When
Shutdown
TTL-Logic-Controlled Shutdown Input
Custom Voltage Available
Ultra-Fast Response in Line/Load
Transient
Quick Start-Up (Typically 50 s)
Current Limiting and Thermal Shutdown
Protection
Applications
PMP/PDA/MP3 players
Cellular and Mobile phone
RF Module
Sensor Module
Pin Configurations
Ordering Information
LP3987 -
□□
□
□□
F:PB-Free
Package Type
B5: SOT-23-5
B3: SOT-23
Output Voltage:
SOT23-5(B5) Type:
Type
A B
Voltage(V) 1.5 1.8
SOT23 (B3) Type:
Type
A B
Voltage(V) 1.5 1.8
C D E H
F
G
2.5 2.7 2.8 2.85 3.0 3.3
C D E H
2.0 2.1 2.5 2.8
F
G
3.0 3.3
SOT-23-5
SOT-23
Typical Application Circuit
Note:
1.
Output Voltage range from 1.5V to 3.3V;
2.
2.85V output order is LP3987-HB5F.
LP3987-datasheet
Oct.-2003
1-1
LP3987
Functional Pin Description
Pin Name
EN
BP
GND
VOUT
VIN
Pin Function
Chip Enable (Active High). Note that this pin is high impedance. There should be a pull
low 100kΩ resistor connected to GND when the control signal is floating.
Reference Noise Bypass
Ground
Output Voltage
Power Input Voltage
Function Block Diagram
Absolute Maximum Ratings
Supply Input Voltage-----------------------------------------------------------------------------------------------------------6V
Power Dissipation, PD @ TA = 25°C
SOT-23-5 --------------------------------------------------------------------------------------------------------------------400mW
Package Thermal Resistance
SOT-23-5,
θJA
-------------------------------------------------------------------------------------------------------------250°C/W
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------260°C
Storage Temperature Range --------------------------------------------------------------------------------−65°C to 150°C
ESD Susceptibility
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------------2kV
MM(Machine-Mode)-----------------------------------------------------------------------------------------------------------200V
Recommended Operating Conditions
Supply Input Voltage-----------------------------------------------------------------------------------------------2.5V to 5.5V
EN Input Voltage ------------------------------------------------------------------------------------------------------0V to 5.5V
Operation Junction Temperature Range --------------------------------------------------------------−40°C to 125°C
Operation Ambient Temperature Range-----------------------------------------------------------------−40°C to 85°C
LP3987-datasheet
Oct.-2003
2-2
LP3987
Electrical Characteristics
(VIN = VOUT + 1V, CIN = COUT = 1µF, CBP = 22nF, TA = 25° C, unless otherwise specified)
Parameter
Output Voltage Accuracy
Current Limit
Quiescent Current
Dropout Voltage
Line Regulation
Load Regulation
Standby Current
EN Input Bias Current
Logic-Low
EN Threshold
Voltage
Logic-High
Voltage
Output Noise Voltage
Power Supply
f = 100Hz
V
IH
e
NO
PSRR
V
IN
= 3V to 5.5V, Start-Up
10Hz to 100kHz, I
OUT
=
200mA C
OUT
= 1µF
Symbol
ΔV
OUT
I
LIM
I
Q
V
DROP
ΔV
LINE
ΔV
LOAD
I
STBY
I
IBSD
V
IL
Test Conditions
I
OUT
= 1mA
R
LOAD
= 1Ω
V
EN
≥
1.2V, I
OUT
= 0mA
I
OUT
= 200mA, V
OUT
> 2.8V
I
OUT
= 300mA, V
OUT
> 2.8V
V
IN
= (V
OUT
+ 1V) to 5.5V,
I
OUT
= 1mA
1mA < I
OUT
< 300mA
V
EN
= GND, Shutdown
V
EN
= GND or VIN
V
IN
= 3V to 5.5V,
Shutdown
Min
−2
360
Typ
--
400
90
170
220
Max
+2
Units
%
mA
130
200
300
0.3
0.6
μA
mV
%
%
μA
nA
0.01
0
1
100
0.4
V
1.2
100
−80
μ
V
RMS
DB
Rejection Rate
f=
10kHz
TSD
COUT = 1µF, IOUT =
10mA
−55
165
Thermal Shutdown Temperature
°C
LP3987-datasheet
Oct.-2003
3-3
LP3987
Typical Operating Characteristics
LP3987-datasheet
Oct.-2003
4-4
LP3987
LP3987-datasheet
Oct.-2003
5-5
