SEMTECH SC560

SC560
Dual Output Low Noise LDO
Linear Regulator
POWER MANAGEMENT
Features
Description
„
The SC560 is a family of dual output, ultra-low dropout
linear voltage regulators designed for use in battery
powered wireless applications. The SC560A, SC560B, and
SC560C provide adjustable output voltages that can be
set using two external resistors. Fixed output voltages
are also available (see ordering information for available
combinations). Fixed output devices provide the powergood monitor, independent enable pins, and a bypass pin
for low-noise operation
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Input voltage range — 2.5V to 5.5V
Output voltage ranges — 1.2V to 5.0V (each LDO)
Maximum output current — 300mA (both LDOs)
Dropout at 200mA load — 200mV max.
Quiescent supply current — 100μA (both LDOs
enabled)
Shutdown current — 100nA (typ)
Output noise < 50μVRMS (SC560A and fixed output
versions)
PSRR < -65dB at 1kHz (SC560A and fixed output
versions)
Over-temperature protection
Short-circuit protection
Under-voltage lockout
Power good monitor for output A (SC560C and fixed
output versions)
Independent enable/disable for LDOB (SC560B and
fixed output versions)
MLPQ-UT8, 1.5mm x 1.5mm x 0.6mm package
Applications
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PDAs and cellular phones
GPS devices
Palmtop computers and handheld instruments
TFT/LCD applications
Wireless handsets
Digital cordless phones and PCS phones
Personal communicators
Wireless LAN
All members of the SC560 family require an input voltage
level between 2.5V and 5.5V. Output voltages for the
adjustable versions can vary between 1.2V and 5.0V. Fixed
output voltage options are also chosen from this range.
The SC560A provides superior low-noise performance
by using an external bypass capacitor connected to pin
7 to filter the bandgap reference. The SC560B uses pin 7
as a separate enable pin for the second regulator output
so the two outputs can be controlled independently.
The SC560C uses this pin to provide a PGOOD output
to hold a processor in reset when the voltage on OUTA
is not in regulation. All other versions provide all three
functions with fixed output voltages (no feedback pins
are provided).
The device also provides protection circuitry such as
current limiting, under-voltage lockout, and thermal
protection to prevent device failures. Stability is
maintained by using 1μF capacitors on the output pins.
The MLPQ-UT8 package and 0402 ceramic capacitors
minimize the required PCB area.
Typical Application Circuit
SC560D
VIN
VIN
EN
EN
OUTA
ENB
OUTB
ENB
CIN
2.2μF
March 28, 2008
PGOOD
PGOOD
GND
BYP
OUTA
OUTB
CBYP
22nF
© 2008 Semtech Corporation
COUTA
1μF
COUTB
1μF
1
SC560
Pin Configuration
Ordering Information
Device
Package
SC560xULTRT(1)(2)(3)
MLPQ-UT8 1.5×1.5
SC560xEVB(3)
Evaluation Board
8
1
7
TOP VIEW
6
2
Notes:
(1) Available in tape and reel only. A reel contains 3,000 devices.
(2) Available in lead-free package only. Device is WEEE and RoHS
compliant.
(3) The device variant is denoted by the x.
5
3
4
MLPQ-UT-8; 1.5x1.5, 8 LEAD
θJA = 157°C/W
Marking Information
Pinout and Voltage Options
Output Voltage
Options
Pin Options
Device
0n
yw
Part
No.
Code
Pin 4
Pin7
Pin 8
VLDOA
VLDOB
SC560A
FBA
BYP
FBB
ADJ
ADJ
0A
SC560B
FBA
ENB
FBB
ADJ
ADJ
0B
SC560C
FBA
PGOOD
FBB
ADJ
ADJ
0C
SC560D
ENB
BYP
PGOOD
2.8V
1.8V
0D
SC560E
ENB
BYP
PGOOD
2.85V
2.85V
0K
SC560F
ENB
BYP
PGOOD
2.5V
1.8V
0L
SC560G
ENB
BYP
PGOOD
2.8V
1.5V
0U
SC560H
ENB
BYP
PGOOD
3.3V
3.3V
0S
0n = Part No. Code
See Pinout and Voltage Options Table for details
yw = Datecode
2
SC560
Absolute Maximum Ratings
Recommended Operating Conditions
VIN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.5
Ambient Temperature Range (°C) . . . . . . . . . -40 < TA < +85
EN, ENB (V) . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VIN + 0.3)
VIN (V) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 < VIN < 5.5
PGOOD (V) . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VIN + 0.3)
VOUTA, VOUTB (V) .... . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 < VOUT < 5.0
Pin Voltage — All Other Pins (V) . . . . . . . . . -0.3 to (VIN + 0.3)
OUTA, OUTB Short Circuit Duration . . . . . . . . Continuous
ESD Protection Level(1) (kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Thermal Information
Thermal Resistance, Junction to Ambient(2) (°C/W) . . . 157
Maximum Junction Temperature (°C) . . . . . . . . . . . . . . +150
Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) Tested according to JEDEC standard JESD22-A114-B.
(2) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
Electrical Characteristics
Unless otherwise noted VIN = 3.6V, CIN = 2.2μF, COUTA = COUTB = 1μF, VEN = VENB = VIN, TA = -40 to +85°C. Typical values are at TA = 25°C. All
specifications apply to both LDOs unless otherwise noted.
Parameter
Input Supply Voltage Range
Output Voltage
Symbol
Conditions
Min
Typ
Max
Units
VIN
2.5
5.5
V
VOUTx
1.2
5.0
V
-3
3
%
Output Voltage Accuracy
ΔVOUTx
VIN = 2.5V to 5.5V, IOUTx = 0 to 300mA
Maximum Output Current
IMAX
Dropout Voltage(1)
VD
IOUTx = 200mA, VOUTx = 2.5V to 5.0V
100
200
mV
Shutdown Current
ISD
TA = 25°C
0.1
1
μA
Quiescent Current
IQ
IOUTA = IOUTB = 0mA, TA = 25°C
100
Load Regulation
ΔVLOAD
IOUTx = 1mA to IMAX
Line Regulation
ΔVLINE
IOUTx = 1mA
300
mA
-6
Feedback Regulation Voltage(2)
VFB
0.985
Current Limit
ILIM
350
1
μA
20
mV
6
mV
1.015
V
850
mA
3
SC560
Electrical Characteristics (continued)
Parameter
(3)
Noise
Power Supply Rejection
Ratio (3)
PGOOD Delay(4)
Symbol
eN
Conditions
Min
Typ
Max
Units
VIN = 3.7V, IOUTx = 50mA ,
10Hz < f < 100kHz, CBYP = 22nF
50
μVRMS
VIN = 3.7V, IOUTx = 50mA ,
10Hz < f < 100kHz
300
μVRMS
VIN = 3.7V, IOUTx = 50mA, f = 1kHz,
CBYP = 22nF
65
dB
VIN = 3.7V, IOUTx = 50mA, f = 1kHz
40
PSRR
tDELAY
160
200
240
ms
82
87
92
%
V TH-PGOOD
Percentage of nominal output,
VOUTA falling
tSU
From OFF to 87% VOUTx, IOUTx = 50mA,
CBYP = 22nF(2)
1
ms
Power Up Delay Between LDOA and
LDOB(5)
tDELAY
Delay between VOUTA and VOUTB start-ups
128
μs
Under Voltage Lockout
VUVLO
VIN Rising
PGOOD Threshold(4)
Start-Up Time
UVLO Hysteresis
2.15
VUVLO-HYS
Over Temperature Protection
Threshold
TOT
Over Temperature Hysteresis
TOT-HYS
Temperature Rising
2.25
2.35
V
100
mV
160
°C
20
°C
Digital Inputs
Logic Input High Threshold
VIH
VIN = 5.5V
Logic Input Low Threshold
VIL
VIN = 2.5V
0.4
V
Logic Input High Current
IIH
VIN = 5.5V
1
μA
Logic Input Low Current
IIL
VIN = 5.5V
1
μA
VOL
ISINK = 500μA,VIN=3.7V
20
mV
1.25
V
Digital Outputs
PGOOD Output voltage Low
7
Notes:
(1) Dropout voltage is defined as VIN - VOUTx , when VOUTx is 100mV below the value of VOUTx at VIN = VOUTx + 0.5V.
(2) SC560A, SC560B and SC560C only
(3) Except SC560B and fixed output versions
(4) Except SC560A and SC560B
(5) SC560A and SC560C only
4
SC560
Typical Characteristics
Load Regulation — LDOA
Load Regulation — LDOB
VOUTA = 3.3V, VIN = 3.6V
6
7
Output Voltage Variation (mV)
5
Output Voltage Variation (mV)
VOUTB = 2.8V, VIN = 3.6V
8
4
TA=85°C
3
TA=25°C
2
TA=-40°C
6
5
TA=85°C
TA=-40°C
4
3
TA=25°C
2
1
1
0
0
0
50
100
150
200
250
0
50
100
Line Regulation — LDOA
2
150
200
250
Output Current (mA)
Output Current (mA)
Line Regulation — LDOB
VOUTA = 3.3V, IOUTA = 1mA
VOUTB = 2.8V, IOUTB = 1mA
3
Output Voltage Variation (mV)
Output Voltage Variation (mV)
2.5
1.5
1
0.5
TA=85°C
TA=25°C
0
2
1.5
1
TA=85°C
TA=-40°C
0.5
TA=25°C
0
TA=-40°C
-0.5
3.3
3.5
3.7
3.9
4.1
4.3
4.5
4.7
4.9
5.1
5.3
5.5
-0.5
2.9
3.1
3.3
3.5
3.7
3.9
Dropout Voltage LDOA
300
4.1
4.3
4.5
4.7
4.9
5.1
5.3
3
3.05
5.5
Input Voltage (V)
Input Voltage (V)
Dropout Voltage LDOB
VOUTA = 3.3V, IOUTA = 200mA
400
VOUTB = 2.8V, IOUTB = 200mA
350
250
150
VIN - VOUT (mV)
VIN - VOUT (mV)
300
200
TA=85°C
100
250
200
TA=85°C
150
100
TA=25°C
50
0
2.95
3
3.05
3.1
3.15
3.2
3.25
TA=25°C
TA=-40°C
3.3
3.35
Input Voltage (V)
3.4
TA=-40°C
50
3.45
3.5
3.55
3.6
0
2.5
2.55
2.6
2.65
2.7
2.75
2.8
2.85
2.9
2.95
3.1
Input Voltage (V)
5
SC560
Typical Characteristics (continued)
PSRR vs. Frequency (Both LDOs)
0
PSRR vs. Frequency (Both LDOs)
VOUT = 2.8V, Io=50mA, CBYP=22nF
VOUT = 2.8V, IO = 50mA
0
-10
-10
-20
-20
PSRR (dB)
PSRR (dB)
-30
-40
-50
-30
-40
-60
-50
-70
-60
-80
-90
10
100
Frequency (Hz)
1000
-70
10
10000
450
VOUT = 2.8V, VIN = 3.7V, no CBYP
400
50
Output Voltage Noise (μV)
T=85°C
60
T=25°C
40
T=-40°C
30
10000
Output Noise vs. Load Current (Both LDOs)
VOUT = 2.8V, VIN=3.7V, CBYP=22nF
70
Output Voltage Noise (μV)
1000
Frequency (Hz)
Output Noise vs. Load Current (Both LDOs)
80
100
20
10
TA=85°C
350
TA=25°C
300
TA=-40°C
250
200
150
100
50
0
0
0
50
100
150
200
250
0
50
100
150
200
250
Output Current (mA)
Output Current (mA)
Load Transient Response
Rising Edge (Both LDOs)
Load Transient Response
Falling Edge (Both LDOs)
VIN = 3.6V, VOUT = 2.8V
VIN = 3.6V, VOUT = 2.8V
IOUT=10mA to
200ma
(100mA/div)
IOUT=10mA to
200ma
(100mA/div))
VOUT
(10mV/div)
VOUT
(10mV/div)
6
SC560
Pin Configurations and Descriptions
Pin #
Pin
Name
SC560A
SC560B
SC560C
SC560
Fixed Output
1
1
1
1
OUTB
2
2
2
2
VIN
3
3
3
3
OUTA
4
4
4
5
5
5
6
6
6
7
7
7
8
8
8
Pin Function
Output for LDOB
Input supply voltage terminal
Output for LDOA
FBA
Feedback sense pin for LDOA — Connect this pin to an
external resistor divider to set VOUTA
5
GND
Analog and digital ground
6
EN
Logic input — active HIGH enables both LDOs for the SC560A and
SC560C, or LDOA for all other variants.
7
BYP
LDO bypass output — Bypass with a 22nF capacitor
4
ENB
Logic input — active HIGH enables LDOB for SC560B and SC560D
8
PGOOD
Power Good output — monitors the level of LDOA, switches low
when the output drops out of regulation.
FBB
Feedback sense pin for LDOB — Connect this pin to an external
resistor divider to set VOUTB
7
SC560
Block Diagrams
SC560A
VIN
2
VIN
VREF
7
BYP
3
OUTA
4
FBA
1
OUTB
8
FBB
3
OUTA
4
FBA
1
OUTB
8
FBB
UVLO
VIN
GND
EN
5
O/T
VIN
PowerON
Logic
6
LDOA
LDOB
SC560B
VIN
2
VIN
VREF
UVLO
VIN
GND
EN
ENB
5
6
7
O/T
PowerON
Logic
LDOA
VIN
LDOB
8
SC560
Block Diagrams (continued)
SC560C
VIN
2
VIN
7
PGOOD
3
OUTA
4
FBA
1
OUTB
8
FBB
7
BYP
8
PGOOD
LDOA
3
OUTA
LDOB
1
OUTB
VREF
PGOOD
Logic
UVLO
VIN
GND
EN
5
O/T
VIN
PowerON
Logic
6
LDOA
LDOB
SC560 – Fixed Output Versions
VIN
2
VIN
VREF
PGOOD
Logic
UVLO
VIN
GND
5
EN
6
ENB
4
O/T
PowerON
Logic
VIN
9
SC560
Applications Information
General Description
The SC560 is a family of dual output linear regulator devices
intended for applications where low dropout voltage, low
supply current, and low output noise are critical. Each
device provides a very simple, low cost solution for two
separate regulated outputs. Very little PCB area is required
due to the miniature package size and the need for only
four external capacitors.
The linear regulators LDOA and LDOB are powered from
a single input supply rail, and each provides 300mA of
output current. The SC560 can provide output voltages
in the range 1.2V to 5.0V. The output voltages for the
SC560A, SC560B and SC560C are set by connecting
external resistor dividers to the feedback pins of each
LDO. All other versions of the SC560 have fixed output
voltage values shown in the Pinout and Voltage Options
table.
The SC560B and the fixed output variants provide
a separate enable pin for LDOB which allows LDOA
and LDOB to be enabled independently. The EN pin
controls the LDOA output and the ENB provides the
same functionality relative to the LDOB output. The
table shown below lists the effect of the polarity of the
EN and ENB signals on the outputs of LDOA and LDOB.
Since LDOB can be enabled separately, there is no timing
relationship between the two outputs at startup.
EN
ENB
LDOA
LDOB
Low
Low
Off
Off
Low
High
Off
Off
High
Low
On
Off
High
High
On
On
Power On Control
The SC560A and SC560C devices have a single enable pin
(EN) that controls both LDO outputs. Pulling this pin low
causes the device to enter a low power shutdown mode
where it typically draws 100nA from the input supply.
When EN transitions high, the output of LDOA is enabled.
After a delay of 128μs, the output of LDOB is enabled. In
the SC560C, when the output voltage of LDOA reaches
87% of its regulation point, the delay timer starts and the
PGOOD signal transitions high after a delay of 200ms. The
power up/down sequence is shown in the timing diagram
in Figure 1.
The SC560C and the fixed output variants have a PGOOD
signal which monitors the output of LDOA and transitions
high 200ms after LDOA has reached 87% of its regulation
point. This can be used to hold a processor in reset when
the output voltage is out of regulation.
Output Voltage Selection
The output voltage of each LDO for the SC560A, SC560B,
and SC560C version is set independently using external
resistor dividers. Figure 2 illustrates the proper connection
for LDOA.
OUTA
EN
87%
OUTA
87%
200ms
FBA
R1
R2
PGOOD
128 μs
OUTB
Figure 1 — Timing Diagram
Figure 2 — Output Voltage Feedback Circuit
10
SC560
Applications Information (continued)
The values of the resistors in the voltage divider network
can be calculated using the equation:
VOUT
VREF
R1 R2 R2
where VREF = 1V. The value of R2 should be 100kΩ or
less to ensure noise performance and stability. Values
significantly less than 100kΩ will impact the quiescent
current.
Protection Features
The SC560 family provides the following protection
features to ensure that no damage is incurred in the
event of a fault condition:
Under-Voltage Lockout
Over-Temperature Protection
Short-Circuit Protection
•
•
•
Under-Voltage Lockout
The Under-Voltage Lockout (UVLO) circuit protects the
device from operating in an unknown state if the input
voltage supply is too low.
Short-Circuit Protection
Each output has short-circuit protection. If the output
current exceeds the current limit, the output voltage will
drop and the output current will be limited until the load
current returns to a specified level. If a short-circuit occurs
on the output of LDOA, the output of LDOB will also be
disabled until the fault is removed and the load current
returns to a specified level.
Component Selection
A capacitance of 1μF or larger on each output is
recommended to ensure stability. Ceramic capacitors
of type X5R or X7R should be used because of their
low ESR and stable temperature coefficients. It is also
recommended that the input be bypassed with a 2.2μF,
low ESR X5R or X7R capacitor to minimize noise and
improve transient response. Note: Tantalum and Y5V
capacitors are not recommended.
The BYP pin on the SC560D and the fixed output versions
must have a minimum of 22nF connected to ground to
meet all noise-sensitive requirements. Increasing the
capacitance to 100nF will further improve PSRR and
output noise.
When the VIN drops below the UVLO threshold, the LDOs
are disabled and PGOOD is held low (SC560C and fixed
output variants only). When VIN is increased above the
hysteresis level, the LDOs are re-enabled into their
previous states, provided EN has remained high. When
powering up with VIN below the UVLO threshold, the
LDOs remain disabled and PGOOD is held low (SC560C
and fixed output variants only).
Over-Temperature Protection
An internal Over-Temperature (OT) protection circuit is
provided that monitors the internal junction temperature.
When the temperature exceeds the OT threshold as
defined in the Electrical Characteristics section, the OT
protection disables both LDO outputs and holds the
PGOOD signal low. When the junction temperature drops
below the hysteresis level, the LDOs are re-enabled into
their previous states and PGOOD transitions high after a
200ms delay, provided EN has remained high (SC560C
and fixed output variants only).
11
SC560
Applications Information (continued)
Thermal Considerations
Although each of the two LDOs in the SC560 can provide
300mA of output current, the maximum power dissipation
in the device is restricted by the miniature package size.
The graphs in Figure 3 and Figure 4 can be used as a
guideline to determine whether the input voltage, output
voltages, output currents, and ambient temperature of the
system result in power dissipation within the operating
limits are met or if further thermal relief is required.
0.6
TJ = TA +(PD x θJA)
where
TJ = Junction Temperature (°C)
TA = Ambient Temperature (°C)
PD = Power Dissipation (W)
θJA = Thermal Resistance Junction to Ambient (°C/W)
0.5
0.4
Maximum Recommended Input Voltage
Maximum Total Output Current (A)
0.7
The following procedure can be followed to determine if
the thermal design of the system is adequate. The junction
temperature of the SC560 can be determined in known
operating conditions using the following equation:
Vo=3.3V
Vo=1.5V
0.3
0.2
0.1
______
TA=+25°C, PD(MAX)= 0.8W
- - - - TA=+85°C, PD(MAX)= 0.41W
0
2.5
3
3.5
4.5
4
Input Voltage (V)
5
5.5
Example
An SC560D is used to provide outputs of 2.8V, 150mA from
LDOA and 1.8V, 200mA from LDOB. The input voltage is
4.2V, and the ambient temperature of the system is 40°C.
PD= 0.15(4.2 – 2.8) + 0.2(4.2 – 1.8)
= 0.69W
6
and
Figure 3 — Safe Operating Limit
TJ = 40 + (0.69 x 157) = 148.3°C
1.6
Figures 3 and 4 show that the junction temperature
would be within the maximum specification of 150°C
for this power dissipation. This means that operation of
the SC560 under these conditions is within the specified
limits and the device would not require further thermal
relief measures.
Maximum Power Dissipation (W)
1.4
1.2
1
TJ(Max)=150°C
0.8
0.6
TJ(Max)=125°C
0.4
0.2
0
-40
-20
0
60
20
40
Ambient Temperature (oC)
80
100
Figure 4 — Maximum PD vs. TA
12
SC560
Applications Information (continued)
Layout Considerations
•
While layout for linear devices is generally not as critical as
for a switching application, careful attention to detail will
ensure reliable operation. The diagram below illustrates
proper layout of a circuit using the SC560A.
•
•
•
Connect all ground connections directly to the
ground plane whenever possible to minimize
ground potential differences on the PCB.
Ensure that the feedback resistors are placed as
close as possible to the feedback pins.
Attach the part to a large copper footprint, to
enable better heat transfer from the device
on PCBs where there are internal power and
ground planes.
Place the input, output, and bypass capacitors
close to the device for optimal transient
response and device behavior.
R4
C3
R3
1
C1
C2
U1
C4
R1
R2
U1 = SC560A
13
SC560
Outline Drawing — MLPQ-UT8
D
A
B
PIN 1
INDICATOR
(LASER MARK)
DIMENSIONS
INCHES
MILLIMETERS
DIM
MIN NOM MAX MIN NOM MAX
.018
.024 0.45
0.60
A
.002 0.00
0.05
A1 .000
(.006)
(0.1524)
A2
b
.006 .008 .010 0.15 0.20 0.25
.059 BSC
1.50 BSC
D
.059 BSC
1.50 BSC
E
e
.016 BSC
0.40 BSC
0.12 .014 0.16 0.30 0.35 0.40
L
8
8
N
aaa
.004
0.10
.004
0.10
bbb
E
A2
A
SEATING
PLANE
aaa C
C
A1
LxN
e
2
0.20
0.25
1
N
bxN
0.17
bbb
C A B
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS.
14
SC560
Land Pattern — MLPQ-UT8
Z
DIMENSIONS
G
P
2X (C)
(G)
INCHES
MILLIMETERS
C
(.057)
(1.45)
G
.028
0.70
P
.016
0.40
R
.004
0.10
X
.008
0.20
Y
.030
0.75
Z
.087
2.20
(Z)
X
R
DIM
Y
NOTES:
1.
CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2.
THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 Fax: (805) 498-3804
www.semtech.com
15