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PDF SC900A Data sheet ( Hoja de datos )
| Número de pieza | SC900A | |
| Descripción | Programmable Penta ULDO | |
| Fabricantes | Semtech | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de SC900A (archivo pdf) en la parte inferior de esta página. Total 23 Páginas | ||
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POWER MANAGEMENT
Description
SC900A
Programmable Penta ULDO
with RESET anwdwwI.D2aCtaSIhneette4Ur.cfoamce
Features
The SC900A is a highly integrated power management de-
vice for low power portable applications. The device con-
tains five adjustable low-dropout linear regulators (LDOs)
with CMOS pass-devices as well as a band-gap reference,
I2C interface, and DACs to control the output voltages.
Many features of the SC900A are programmable through
the I2C interface. These include the ability to independent-
ly turn on any combination of the five regulators. All five
of the LDO output voltages are programmable in 50mV
steps from 1.45V to 3.00V for LDOs A and B, and from
1.75V to 3.30V for LDOs C, D and E. Each LDO can have
an active shutdown or nonactive shutdown program op-
tion through the interface. There is also a reset monitor
flag that is associated with LDOA. In addition, the device
has a separate programmable power good monitor flag
that activates when one or more LDOs go out of regula-
tion.
The SC900A offers significant quiescent current and
space savings to the system designer by sharing refer-
ence and biasing among five LDOs. The small and ther-
mally efficient 20-lead MLPQ package make it ideal for
use in portable products where minimizing layout area is
critical.
Five LDO regulators in one package
I2C interface with multiple device capability
Independent I2C enable/disable of LDOs
Independent I2C control of output voltages
Low thermal impedance of 40°C per watt
150mV dropout at 150mA
Input range from 2.7V to 5.5V
Programmable power good flag
Minimal number of external components
Over temperature protection
Small 4mm x 4mm 20-lead MLPQ package
Small input/output filter capacitors
Programmable VOUT range -
1.45V to 3.00V for LDOs A and B
1.75V to 3.30V for LDOs C, D and E
Applications
Palmtop/Laptop computers
Personal Digital Assistants
Cellular telephones
Battery-powered equipment
High efficiency linear power supplies
Typical Application Circuit
+
-
VBAT
4.7uF
SC900A
VIN
INA
INB
INCD
INE
EN
LDOPGD
ARST
SDA
SCL
A0
GND
LDOE
LDOD
LDOA
LDOB
LDOC
VREF
VASEL
DGND
2.2uF 2.2uF 2.2uF
0.1uF
Keypad
Baseband
Processor
Audio
Processing
Digital
Interface
2.2uF
2.2uF
Receiver
Section
LNA
TCXO
&
Synthesiser
Transmitter
Section
PA
Camera
Processing
CCD
November 14, 2005
1
www.semtech.com
1 page  
SC900A
POWER MANAGEMENT
Electrical Characteristics (Cont.)
www.DataSheet4U.com
Parameter
Symbol
Conditions
Min
LDO Regulator D (Cont.)
Maximum Output Current
Default Setting: OFF
Line Regulation at 3.10V
Load Regulation at 3.10V
Dropout Voltage
Power Supply Rejection Ratio
Output Voltage Noise(2)
LDO Regulator E
IOMAXD
VOD
LINEREGD
LOADREGD
VDD
PSRRD
en-D
IOUT = 1mA, VOUT + 0.15V < VIN < 5.5V
1mA < IOUT <150mA
VOUT = 3.3V, IOUT = 150mA
f = 10Hz - 1kHz, CBYP = 0.1mF,
IOUT = 50mA,
2.5V ≤ VOUT ≤ 3.3V
f = 10Hz - 100kHz, IOUT = 50mA,
CVREF = 0.1μF, COUT = 2.2μF,
2.5V ≤ VOUT ≤ 3.3V
Output Voltage Accuracy
Output Voltage Accuracy at
3.10V (DAC = 10111)
Maximum Output Current
Default Setting: OFF
Line Regulation at 3.10V
Load Regulation at 3.10V
VOAE
VOASE
IOMAXE
VOE
LINEREGE
LOADREGE
1.75V ≤ VOUT ≤ 3.30V
VOUT + 0.15V ≤ VIN ≤ 5.5V
IOUT = 1mA, TA = 25°C
IOUT = 1mA
VOUT + 0.5V ≤ VIN ≤ 5.5V,
IOUT = 150mA
IOUT = 1mA, VOUT + 0.15V < VIN < 5.5V
1mA < IOUT = 150mA
Dropout Voltage
Power Supply Rejection Ratio
VDE
PSRRE
Output Voltage Noise(2)
A RESET
en-E
VOUT = 3.3V, IOUT = 150mA
f = 10Hz - 1kHz, CBYP = 0.1μF,
IOUT = 50mA,
2.5V ≤ VOUT ≤ 3.3V
f = 10Hz - 100kHz, IOUT = 50mA,
CVREF = 0.1μF, COUT = 2.2μF,
2.5V ≤ VOUT ≤ 3.3V
Reset Threshold
Reset Active Timeout Delay
RESETTHLD
tRD
Delay in default state
LDO POWER GOOD
PGOOD Threshold
PGOODTHLD
PGOOD Active Timeout Delay
tPG
Delay in default state
Notes:
1) Digital outputs are powered from LDOB, so LDOB must be active for operation of LDOPGD and ARST.
2) Below 2.5V: becomes digital regulator.
© 2005 Semtech Corp.
5
150
-3
-2
-3.5
150
75
75
Typ
3.10
2.5
-3
150
60
55
3.10
2.5
-3
150
60
55
77
100
77
100
Max Units
mA
V
12 mV
-20 mV
190 mV
dB
μVRMS
+3 %
+2 %
+3.5 %
mA
V
12 mV
-20 mV
190 mV
dB
μVRMS
%
125 ms
%
125 ms
www.semtech.com
5 Page 
SC900A
POWER MANAGEMENT
Applications Information (Cont.)
www.DataSheet4U.com
Active Shutdown
The shutdown control bits determine how the on-chip ac-
tive shutdown switches behave. Each LDO register uses
bit 5 of the LDO output voltage data byte to control the
shutdown behavior. When the active shutdown bit is en-
abled (set to 1), the capacitance on the LDO output will be
discharged by an on-chip FET after the LDO is disabled.
When the active shutdown bit is disabled (set to 0), the
output capacitance on the LDO output is discharged by
the load. The default active shutdown state for all LDOs
is on.
ON/OFF Control Register
Each individual LDO may be turned on or off by accessing
the ON/OFF control register. LDOs are turned on by set-
ting their respective on/off bit to 1. Likewise, they can be
turned off by setting the on/off bit to 0. This allows for
on/off control with a single write command. If the enable
(EN) pin is high and data is written to the LDO voltage reg-
isters, the LDO outputs will go to the voltage prescribed by
the Output Voltage Code bits (0-4). Data will not be lost
when toggling the on/off bit from 0 to 1. However, if the
EN pin is forced low, all circuitry in the device is disabled.
All programmed information is lost when the enable bit is
subsequently pulled high.
VASEL Pin
The VASEL pin sets the default voltage of LDO A, the core
supply. When this pin is set to VIN, the default voltage is
2.80V. When this pin is set to GND, the default voltage is
1.80V. The voltage can be changed from its default state
after start up by writing to the LDO voltage code register.
When the A0 pin is tied to GND, device 1 has an address
of 0 and the combination of device type ID and address is
0x08H. When the A0 pin is tied to VIN, device 2 has and
address of 1 and the combination of device type ID and
address is 0x09H.
The last bit of the slave address defines the operation to
be performed. When set to a one a read operation is se-
lected; when set to a zero a write operation is selected.
Following a start condition, the SC900A monitors the SDA
line comparing the slave address being transmitted with
its slave address (device type ID and state of A0 input).
Upon a correct compare the SC900A outputs an acknowl-
edge on the SDA line. Depending on the state of the R/W
bit, the SC900A will execute a read or write operation.
Protection Circuitry
The SC900A provides protection circuitry that prevents
the device from operating in an unspecified state. These
include Under Voltage Lockout Protection, Over-tempera-
ture Protection and Short-circuit Protection.
Under Voltage Lockout
The SC900A provides an Under Voltage Lockout (UVLO)
circuit to protect the device from operating in an unknown
state if the input voltage supply is too low. When the bat-
tery voltage drops below the UVLO threshold, the LDOs
are disabled. As the battery voltage increases above the
hysteresis level, the LDOs are re-enabled into their previ-
ous states, provided ENABLE has remained high. If EN-
ABLE goes low, the SC900A will shut down.
Device Addressing
Following a start condition, the master must output the
address of the slave it is accessing. The most significant
six bits of the slave are the device type identifier (ID). For
the SC900A this is fixed at 000100[B]. The next signifi-
cant bit addresses a particular device. A system can have
up to two SC900A devices on the bus. The two addresses
are defined by the state of the A0 input (see Figure 1).
Over Temperature Protection
The SC900A provides an internal Over-temperature (OT)
protection circuit that monitors the internal junction tem-
perature. When the temperature exceeds the OT thresh-
old, the OT protection disables all the LDO outputs. As
the junction temperature drops below the hysteresis level
the OT protection re-enables all the LDOs in their previous
states, provided ENABLE has remained high. If ENABLE
goes low, the SC900A will shut down.
DEVICE TYPE IDENTIFIER
0 0 01 0
0
DEVICE ADDRESS
Pin A0 to GND = 0
Pin A0 to VIN = 1
R/W
X
Short-Circuit Protection
Each LDO output has short-circuit protection. If a short is
applied to any output, the output voltage will drop and the
Figure 1 - Slave Address Structure
output current will be limited to the short circuit current
until the short is removed.
© 2005 Semtech Corp.
11
www.semtech.com
11 Page | ||
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| PDF Descargar | [ Datasheet SC900A.PDF ] | |
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