SEMTECH SC1452

DUAL 150mA LDO REGULATOR WITH
PROGRAMMABLE RESET
PRELIMINARY - August 7, 2000
SC1452
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
FEATURES
•= Up to 150mA per regulator output
•= Low quiescent current
•= Low dropout voltage
•= Wide selection of output voltages
•= Stable operation with ceramic caps
•= Tight load and line regulation
•= Current and thermal limiting
•= Reverse input polarity protection
•= <1uA off-mode current
•= Logic controlled electronic enable
•= Programmable reset
•= Full industrial temperature range
DESCRIPTION
The SC1452 is a state of the art device intended to
provide maximum performance and flexibility in battery
operated systems. It has been designed specifically to
fully support a single Li-Ion battery and its external
charger voltages.
The SC1452 contains two independently enabled, ultra
low dropout voltage regulators (ULDOs). It operates
from an input voltage range of 2.5V to 6.5V, and a wide
variety of output voltage options are available which are
designed to provide an initial tolerance of ±1% and
±2% over temperature.
Each regulator has an associated active-low reset signal which is asserted when the voltage output declines
below the preset threshold. Once the output recovers,
the reset continues to be asserted (delayed) for a
predetermined time, 50ms for reset A and 150ms for
reset B. In the case of regulator B, the delay time may
be reduced by the addition of an external capacitor.
APPLICATIONS
•= Cellular telephones
•= Palmtop/Laptop computers
•= Battery-powered equipment
•= Bar code scanners
•= SMPS post regulator/dc to dc modules
•= High efficiency linear power supplies
The SC1452 has a bypass pin to enable the user to
capacitively decouple the bandgap reference for very
low output noise (down to 50µVrms).
ORDERING INFORMATION
Part Numbers
The devices utilize CMOS technology to achieve very
low operating currents (typically 150µA with both outputs supplying 150mA). The dropout voltage is typically
165mV at 150mA, helping to prolong battery life. In
addition, the devices are guaranteed to provide 400mA
of peak current for applications which require high initial
inrush current. They have been designed to be used
with low ESR ceramic capacitors to save cost and PCB
area.
SC1452XIMSTR
Package
(1)(2)
MSOP-10
Notes:
(1) Where X denotes voltage options - see table on
page 5.
(2) Only available in tape and reel packaging. A reel
contains 2500 devices.
The SC1452 comes in the low profile 10-lead MSOP
package.
TYPICAL APPLICATION
U1
1
3.3V OUT
2
2.5V OUT
3
4
RESET A
5
RESET B
OUTA
OUTB
IN
ENA
GND
BYP
RSTA
ENB
RSTB
DLYB
10
3.3V IN
9
ENABLE OUTPUT A
8
7
ENABLE OUTPUT B
6
SC1452JIMS
COUTA
1uF
COUTB
1uF
CBYP
10nF
CDLYB
10nF
CIN
1uF
1
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH
PROGRAMMABLE RESET
SC1452
PRELIMINARY - August 7, 2000
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Maximum
Units
Input Supply Voltage
VIN
-5 to +7
V
Enable Input Voltage
VEN
-5 to +VIN
V
Operating Ambient Temperature Range
TA
-40 to +85
°C
Operating Junction Temperature Range
TJ
-40 to +125
°C
TSTG
-60 to +150
°C
Thermal Resistance Junction to Ambient
θJA
113
°C/W
Thermal Resistance Junction to Case
θJC
42
°C/W
ESD
2
kV
Storage Temperature
ESD Rating (Human Body Model)
ELECTRICAL CHARACTERISTICS
Unless specified: TA = 25°C, VIN = VOUT + 1V, IOUTA = IOUTB = 1mA, COUT = 1.0 µF, VENA = VENB = VIN. Values in bold apply over full operating
temperature range.
Parameter
Symbol
Condition
Min
Typ
Max
Units
6.5
V
150
µA
IN
Input Supply Voltage
VIN
Quiescent Current
IQ
2.5
VENA = 0V, VENB = VIN, IOUTB = 150mA or
90
VENB = 0V, VENA = VIN, IOUTA = 150mA
200
VENA = VENB = VIN, IOUTA = IOUTB = 150mA
150
240
µA
300
VENA = VENB = 0V (OFF)
0.5
1
µA
2
OUTA, OUTB
Output Voltage
Line Regulation
VOUT
REG(LINE)
IOUT = 1mA
-1%
0mA ≤ IOUT =≤ 150mA, VOUT +1V ≤=VIN ≤=5.5V
-2%
VOUT + 1V ≤ VIN ≤ 5.5V, IOUT = 1mA
VOUT
+1%
V
+2%
5
10
mV
12
Load Regulation
REG(LOAD)
0.1mA ≤=IOUT ≤=150mA
-5
-15
mV
-30
Dropout Voltage
VD
IOUT = 1mA
1.1
IOUT = 50mA
55
mV
75
mV
120
IOUT =150mA
165
250
mV
300
Current Limit
ILIM
400
mA
2
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH
PROGRAMMABLE RESET
SC1452
PRELIMINARY - August 7, 2000
ELECTRICAL CHARACTERISTICS (Cont.)
Unless specified: TA = 25°C, VIN = VOUT + 1V, IOUTA = IOUTB = 1mA, COUT = 1.0 µF, VENA = VENB = VIN. Values in bold apply over full operating
temperature range.
Parameter
Symbol
Condition
Min
Typ
Max
Units
PSRR
f = 120Hz, CBYP = 10nF
60
dB
en
f = 10Hz to 99kHz, IOUT = 50mA,
CBYP = 10nF, COUT = 2.2µF
50
µVRMS
tr
CBYP = 10nF
1.5
ms
OUTA, OUTB (Cont.)
Ripple Rejection
Output Voltage Noise
BYP
Start-up Rise Time
ENABLE (ENA, ENB)
Enable Input Threshold
VIH
Enable Input Current
V
1.6
VIL
0.4
IEN
0.2
µA
%VOUT
RSTA, RSTB
Reset Threshold
VTH
Reset A Delay
VOUT falling
88
90
92
VOUT rising
90
92
94
30
50
70
ms
150
210
ms
tRSTA
Reset B Delay
(1)
Reset A, B Output Voltage
tRSTB
VDLYB = 0V
90
VOH
ISOURCE = 0.5mA
80
VOL
ISINK = 1.2mA
%VOUT
0.3
V
DLYB
Delay Voltage Threshold
VDLYB
Delay Source Current
IDLYB
VOUTB < VTH
1.225 1.250 1.275
V
3.0
µA
2.1
3.9
OVER TEMPERATURE PROTECTION
High Trip Level
Hysteresis
THI
150
°C
THYST
20
°C
NOTE:
(1) VOHA will be a percentage of VOUTA, and VOHB will be a percentage of VOUTB.
3
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH
PROGRAMMABLE RESET
SC1452
PRELIMINARY - August 7, 2000
BLOCK DIAGRAM
4
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH
PROGRAMMABLE RESET
SC1452
PRELIMINARY - August 7, 2000
PIN CONFIGURATION
(Top View)
MSOP-10
MARKING INFORMATION
VOLTAGE OPTIONS
Replace X in the part number (SC1452XIMS) by the letter shown
below for the corresponding voltage option:
X
VOUTA (V)
VOUTB (V)
A
1.8
1.8
B
2.5
2.5
C
2.8
2.8
D
3.0
3.0
E
3.3
3.3
F
3.0
2.5
G
3.0
1.8
H
3.0
2.8
J
3.3
2.5
K
3.3
2.8
# = Voltage options (Example: 452F)
yyww = Datecode (Example: 0008)
XXXX = Lot Number (Example: E01102)
PIN DESCRIPTIONS
Pin # Pin Name
Pin Function
1
OUTA
Regulator A output.
2
OUTB
Regulator B output.
3
GND
Ground pin.
4
RSTA
Power on reset for regulator A. Active low when OUTA is below the reset threshold.
5
RSTB
Power on reset for regulator B. Active low when OUTB is below the reset threshold.
6
DLYB
Programmable delay for RESETB. Delay time can be set by connecting a capacitor, CDLYB, between this pin and ground. Ground this pin if using the default delay time.
7
ENB
Active high enable pin for output B. CMOS compatible input. Connect to IN if not being used.
8
BYP
Bypass pin for bandgap reference. Connect a 10nF capacitor, CBYP, between this pin and
ground for low noise operation.
9
ENA
Active high enable pin for output A. CMOS compatible input. Connect to IN if not being used.
10
IN
Input pin for both regulators.
5
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH
PROGRAMMABLE RESET
SC1452
PRELIMINARY - August 7, 2000
APPLICATIONS INFORMATION
voltage is reached. The delay time can be calculated by
rearranging the above equation, solving for t:
Adjusting RSTB Delay Time
t RSTB =
RSTB, the power on reset for regulator B, can be
reduced externally by connecting a capacitor to the
delay time set pin DLYB. If DLYB is connected to
ground, the internally controlled delay time of 150ms
(typ.) will apply.
Referring to the block diagram, as the output of regulator B (VOUTB) rises and reaches the reset threshold
voltage (92% VOUTB(NOM)), two things happen:
1) the internal 150ms timer starts;
2) the 3µA current source turns on, charging CDLYB (if
connected).
C DLYB • 1 .25
= 416 ,667 • C DLYB
3 • 10 − 6
Note that the maximum delay time is 150ms, as RSTB
goes high when either the internal timer or externally
set timer times out, so if tRSTB is set externally for
200ms, the reset delay will still be 150ms. Thus for a
150ms delay, DLYB should be grounded, and for a
delay time less than 150ms, CDLYB can be calculated
using the equation above, or read from the chart below.
1000
tRSTB = 150ms max.
VDLYB =
3 • 10 −6 • t
C DLYB
tRSTB (ms)
100
If DLYB is connected to ground, RSTB goes high
150ms after VOUTB crosses the threshold voltage. If a
capacitor is connected between DLYB and ground, the
voltage at DLYB can be described by the following
equation:
10
1
0.1
0.01
An internal comparator compares this voltage to a
1.25V reference, and triggers the reset high once this
0.1
1
10
100
1000
CDLYB (nF)
6
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH
PROGRAMMABLE RESET
SC1452
PRELIMINARY - August 7, 2000
DEVICE OUTLINE - MSOP-10
LAND PATTERN - MSOP- 10 - DRAWING PENDING
ECN 00-1247
7
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320