AMS3120 - Advanced Monolithic Systems

AMS3120
2A Fast Transient Linear Regulator
General Description
Features
•
•
The AMS3120 is a high performance linear regulator
with very low dropout voltage and excellent transient
response. It is designed to operate with wide input
voltage range of 1.5 – 7Volts making it ideal for two
step conversion while maintaining high efficiency for
many power sensitive applications. The device is
capable of supplying 2A of output current with a
typical dropout voltage of 550mV at 2A. The product
is available in either fixed or adjustable output
voltage.
•
•
•
•
•
•
•
•
The linear regulator has been optimized for noise
sensitive applications.
The device includes an
Enable pin for electrical on/off of the regulator.
Forcing the Enable pin to logic low shuts down the
LDO and reduces the supply current to less than
1µA.
•
•
•
•
The product includes complete short-circuit and
thermal protection. The combination of these two
internal protection circuits gives the device a
comprehensive safety system to safe guard against
extreme adverse operating conditions.
The AMS3120 is available in a thermally enhanced
SOIC-8 EDP package, and it is rated for -40°C to
+125°C temperature range.
•
VIN range: 1.5 – 7V
Fixed and Adjustable output voltage as low
as 0.6V
2A maximum output current
550mV typical dropout voltage at 2A
Low self noise
Optional Power Good (PG) output
Enable (EN) pin for LDO on/off
125µA typical supply current
PSRR >40dB at 10KHz
Stable with Electrolytic, Tantalum or
Ceramic capacitors
Current Limit protection
Over-Temperature Shutdown
-40 to +125°C temperature range
Thermally enhanced SOIC-8 exposed
paddle package
RoHS & WEEE compliant
Applications
•
•
•
•
•
•
Set-top Box
DVD, Blue-ray DVD writers
LCD TVs and LCD monitors
Infotainment
Wireless & RF: applications
Laptops & notebook
Typical Application
VIN= 3.3V
VOUT*
VIN
VOUT=1.8V
AMS3120
CIN=10μF
PG*
EN
COUT = 22μF
ADJ*
GND
* Optional Power Good, Fixed and Adjustable VOUT are available
02/11/2010
www.advanced-monolithic.com
1
Phone (925) 443-0722
Fax (925) 443-0723
AMS3120
2A Fast Transient Linear Regulator
Pin Description (SO-8EP package)
Pin #
Symbol
1
NC
No connection
2
EN
Enable pin. It controls the electrical on/off of the device. When connected to logic
low, the device shuts off and consumes 1µA of current. A logic high will resume
normal operation.
3
VIN
Input supply Voltage. It powers the internal control circuitry and the internal power
switch. Bypass VIN with at ceramic capacitor from this pin to ground.
NC
No Connection
PG
Power Good pin. It is an open collector, active high output that indicates the status
of the output voltage. When output voltage (VOUT) exceeds the PG trip threshold,
the PG pin goes in to a high impedance state. When the device is out of regulation
or shutdown, the PG pin is pulled low. A 10KΩ to 1MΩ resistor should be
connected from PG to VOUT.
5
NC
No Connection
6
VOUT
Output Voltage
ADJ
Provides feedback to error amplifier from the resistive divider that sets the output
voltage.
NC
No Connection
4
7
8,9
GND
Description
Ground
Pin Configuration
SO-8EP (Top View)
02/11/2010
www.advanced-monolithic.com
2
Phone (925) 443-0722
Fax (925) 443-0723
AMS3120
2A Fast Transient Linear Regulator
Absolute Maximum Ratings (1)
Recommended Operating Conditions (2)
Maximum Input Supply Voltage……………..........….… -0.3V to 15V
Enable Voltage (EN)……………....…………...…..…… -0.3V to 15V
Power Good (PG).……………..…..………………….… -0.3V to 15V
Adjustable Voltage (ADJ).…...……………………....…… -0.3V to 3V
Storage Temperature Range……………................. -65⁰C to 150⁰C
Lead Temperature…………………..………….……………..… 260⁰C
Junction Temperature………...………………..…………..…… 125⁰C
Input Voltage………………………………...….………….. 1.5V to 7V
Ambient Operating Temperature……………….…… -40⁰C to 125⁰C
Thermal Information
8L SOIC EP θJA
(3)
…………………………....……….….…...45⁰C/W
Electrical Characteristics
Unless otherwise noted: VIN=3.3V; VOUT=1.8V; CIN=10 µF; COUT=22µF; -40⁰C≤TA=TJ≤85⁰C; TJ(Max)= 125°C; Typical values are TA= 25°C
Parameter
Output Voltage Accuracy
Adjustable Voltage
Adjustable Pin bias current
Maximum Output Current
Load Regulation
Line Regulation
Supply Current
Shutdown Current
Current Limit
Dropout Voltage
Symbol
VOUT
VADJ
IADJ_Bias
IOUT_Max
ISUP
ISHDN
ILIM
VDO
ΔVOUT/ΔVIN
PSRR
Conditions
Adjustable VOUT only
Adjustable VOUT only
Min.
-3
0.588
Typ.
Max.
Units
0.6
10
3
0.612
100
%
V
nA
A
%
%
mA
µA
A
2
IOUT= 0 – 2A
VIN=3.0 – 7.0V; IOUT=100mA
VIN=3.3V, Io=0A
VIN=3.3V, VEN=0V
0.1
0.2
0.2
<1
2.5
IOUT=0.1A; VOUT=90% of VOUT(NOM)
85
IOUT=0.5A; VOUT=90% of VOUT(NOM)
180
IOUT=1A; VOUT=90% of VOUT(NOM)
275
IOUT=2A; VOUT=90% of VOUT(NOM)
550
F=10KHz Io=20mA
40
dB
BW = 100Hz –100 KHz
COUT = 10µF
IOUT = 500mA
125
µV(rms)
0.5
3
mV
Output Noise Voltage
en
Enable Threshold Low
VEN(L)
1.2
V
Enable Threshold High
VEN(H)
1.3
V
Input Enable Low Current
IEN(L)
VEN = 0V
Input Enable High Current
IEN(H)
VEN = 1.5V
Power Good Low Threshold
Power Good High Threshold
VPG
VPG
% of VOUT PG ON
% of VOUT PG OFF
Power Good Output Low Voltage
VPGL
IPG_SINK = 500μA, Fault Condition
200
Power Good Leakage Current
Thermal Shutdown
Thermal Shutdown Hysteresis
IPG
TSD
PG off, VPG = 12V
0.01
145
15
Notes:
1.
2.
3.
TSD_HYS
0
10
nA
150
300
nA
97
%
%
300
mV
89
μA
°C
°C
Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device.
Measured on approximately 1” square of 1 oz. copper.
The total power dissipation for SO-8 EDP package is recommended to 2.5W rated at 25⁰C ambient temperature. The thermal resistance Junction to Case
is 45⁰C/W. Total power dissipation for the switching regulator and the LDO should be taken in consideration when calculating the output current capability
of each regulator
02/11/2010
www.advanced-monolithic.com
3
Phone (925) 443-0722
Fax (925) 443-0723
A
AMS3
3120
2A Fas
st Transien
nt Linear Regulator
1.808
1.806
1.804
1.802
1.800
1.798
1.796
1.794
1.792
Ou
utput Voltage
e Temperaturre Variation
(Fixed Voltage Option) VO = 1.8V
0.603
0.601
0.599
0.597
0.595
25
0
25
5 50 75 100 125
-2
Ambient Te
emperature (ºC)
(
Dro
opout Voltag
ge vs. Tempe
erature
1.0
0.8
0.1
0.0
-0.1
-0.2
2A
0.6
0.4
0.2
1 A
0.0
3
4
5
6
Input Voltage (V)
7
-50
Load Regulation
0.3
-25
0
25
5 50 75 100 125
Ambient Te
emperature (°C)
(
Dropout Voltage
e vs. Output Current
0.6
0.5
0.2
Voltage (V)
Output
p Voltage
g Change
g (%)
( )
Ad
djust (ADJ) Voltage
V
Temp
perature
Variation (Adjus
stable Voltage Option)
-50
Line Regullation VOUT = 2.5V
0.2
0.605
-25
0
25 50 75
5 100 125
5
Ambient Temperature
T
e (ºC)
Voltage (V)
Output
p Voltage
g Error (%)
( )
-50
Adjustable Voltage (V)
Output
p Voltage
g (V)
( )
Ty
ypical Perfo
ormance Characteris
C
stics (TA = 25°C
2
unless otherwise
o
sp
pecified)
0.1
0.0
-0.1
0.4
0.3
0.2
-0.2
0.1
-0.3
0.0
0.0
02/11/2010
0
0.1
1.0
Output Current (A)
10.0
0
VOUT
= 2.5V
O
0
www.ad
dvanced-mono
olithic.com
4
0.5
1
1.5
Output Current (A)
2
Phone (925)) 443-0722
Fax (925)) 443-0723
AMS3120
2A Fast Transient Linear Regulator
Typical Performance Characteristics (TA = 25°C unless otherwise specified)
IGND vs. Output Current VO=1.8V, VIN=2.5V
1.5
70
Ground Current (mA)
Shutdown Current (µA)
Shutdown Current vs. Input Voltage
125°C
1.0
0.5
‐50°C & 25°C
0.0
0
1
2
3
4
5
6
7
60
50
40
30
20
10
0
0.0
0.8
1.2
1.6
2.0
Output Current (A)
Input Voltage (V)
Load Transient
100mA to 1.5A, VOUT=1.8V,VIN=3.3V, CIN=COUT=22µF
Enable Start-Up
550mA, VOUT=1.8V,VIN=3.3V, CIN=COUT=22µF
V OUT
50mVac
/div
V OUT
1V /div
ISW OUT
500mA
/div
Enable
1V/div
100 µsec/div
10 µsec/div
02/11/2010
0.4
www.advanced-monolithic.com
5
Phone (925) 443-0722
Fax (925) 443-0723
AMS3120
2A Fast Transient Linear Regulator
Functional Block Diagram
Figure 1: Block Diagram of AMS 3120 with Power Good and Adjustable Voltage option
Figure 2: Block Diagram of AMS 3120 with Power Good and Fixed Voltage option
Figure 3: Block Diagram of AMS 3120 with Fixed Voltage option only
02/11/2010
www.advanced-monolithic.com
6
Phone (925) 443-0722
Fax (925) 443-0723
AMS3120
2A Fast Transient Linear Regulator
Table 1: Adjustable Feedback Resistor values
R1 (kΩ)
VOUT (V)
(R2=10kΩ)
1.8
20.0
2.5
31.6
3.3
45.3
5.0
73.2
Device Summary
The AMS3120 is a high voltage low drop out linear
regulator with a current capability of up to 2A. The LDO
has an input voltage range of 1.5V to 7V with an output
voltage as low as 0.6V and is stable with a wide range of
ceramic, tantalum, and electrolytic output capacitors.
Shutdown/Enable
The Enable (on/off) input threshold voltage is 1.2V.
When disabled the LDO quiescent current decreases to
a typical value of <1µA.
Fault Protection
Short circuit and over-temperature shutdown disable the
converter and LDO in the event of an overload condition.
Overtemp shutdown disables the device when the
junction temperature exceeds 145 ºC. The output
current is internally limited to 2.5A.
PCB Layout
The following guidelines should be followed to insure
proper layout.
1.
2.
Input Capacitor
An input bypass capacitor ranging from 1µF to 10µF is
required. The capacitor should be placed as close as
possible to the device and not be placed more than 1
inch from the LDO.
Output Capacitor
The output capacitor requirements range from the
minimum value required to guarantee stability to larger
values required to meet the extreme transient response
requirements. Values range from 10 to 22µF X5R
ceramic capacitors. Due to the extreme voltage
coefficient of X5R ceramic capacitors, the voltage rating
should be at least double the maximum applied voltage.
Adjustable Version: Feedback Resistor Selection
Choosing AMS 3120 with adjustable output voltage
option allows the user to select an output voltage by
using an external resistor divider. AMS 3120 uses a
0.6V reference voltage at the positive terminal of the
error amplifier. To set the output voltage a programming
resistor from the adjust pin (ADJ) to ground must be
selected (See Pg.1). A 10kΩ resistor is a good selection
for a programming resistor R2. A higher value may result
in an excessively sensitive feedback node while a lower
value will draw more current and degrade the light load
efficiency. The equation for selecting the voltage specific
resistor is:
R4=
Vout
Vref
-1 ·R3 =
5V
0.6V
-1 ·10kΩ=73.2kΩ
3.
4.
VIN Capacitor. A low ESR ceramic bypass capacitor
must be placed as close to the IC as possible.
Adjustable (ADJ) Feedback Resistors. The
adjustable feedback resistors should be placed as
close as possible the IC. Minimize the length of the
trace from the feedback pin to the resistors. This is a
high impedance node susceptible to interference
from external RF noise sources.
Ground.
For good thermal performance vias are required to
couple the exposed tab of the SO-8 package to the
PCB ground plane. The via diameter should be
0.3mm to 0.33mm positioned on a 1.2mm grid.
Power Good
During operation, fault conditions
can occur
unexpectedly. Such conditions include input voltage
dropout (low VIN), overheating, or overloading (excessive
output current). If any of these conditions occurs, the PG
pin will set an “error flag”. The PG pin, which is an opencollector output, will go LOW when VOUT is less than 95%
or the specified output voltage. When the voltage at VOUT
is greater than 95% of the specified output voltage, the
PG pin is HIGH. A logic pull-up resistor of 10KΩ is
recommended at this output. The pin can be left
disconnected if unused.
Output Power and Thermal Limits
The AMS3120 junction temperature and current
capability depends on the internal dissipation and the
junction to case thermal resistance of the SO8 exposed
paddle package.
Additionally, the paddle and PCB temperature will be
elevated due to the total losses of the LDO and of other
circuits mounted to the PCB.
Tjmax=Pd·θjc+Tpcb+Tamb
The internal losses contribute to the junction temperature
rise above the paddle and PCB temperature.
02/11/2010
www.advanced-monolithic.com
7
Phone (925) 443-0722
Fax (925) 443-0723
AMS3120
2A Fast Transient Linear Regulator
Figure 4: AMS3120 SOIC-8 Adjustable Option
Evaluation Board - Top Side
Figure 5: AMS3120 SOIC-8 Adjustable Option
Evaluation Board - Bottom Side
R2
10.0k
Enable
1
2
1
2
Vin
3
C1
10uF
gnd
4
U1
NC
EN
GND
ADJ
VIN VOUT
NC
NC
8
R1
20.0k
7
C3
5.6nF
Vout
6
5
C2
22uF
gnd
AMS3120-8
Figure 4. AMS3120 Evaluation Board Schematic
Component
C1,C2
C3
R2
R1
U1
02/11/2010
Value
Table 2. Evaluation Board Bill of Materials
Manufacturer Manufacturer Part Number
22µF, 10V, X5R, 0805, Ceramic
5.6nF 0603 20%
10kΩ, 0.1W, 0603 1%
See table 2
Low Drop Out Linear Regulator
Taiyo Yuden
LMK212BJ226MG-T
Various
Various
AMS
CRCW060310K0FKEA
CRCW0603xxKxFKEA
AMS3120
www.advanced-monolithic.com
8
Phone (925) 443-0722
Fax (925) 443-0723
AMS3120
2A Fast Transient Linear Regulator
Ordering Information
Device
AMS3120S(1)(2)
Package
SOIC-8 EDP
AMS3120S-PG(1)(2)
(1)(2)
SOIC-8 EDP
AMS3120S-XXPG
SOIC-8 EDP
(1)(2)
SOIC-8 EDP
AMS3120S-XX
Notes:
1. Available in tape and reel only. A reel contains 2,500 devices.
2. Available in lead-free package only. Device is fully WEEE and RoHS compliant
3. Need to specify output voltage option ( )
4.
Outline Drawing and Landing Pattern
Package dimensions are inches (millimeters) unless otherwise noted.
02/11/2010
www.advanced-monolithic.com
9
Phone (925) 443-0722
Fax (925) 443-0723