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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
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. The SC1452 has a bypass pin to enable the user to capacitively decouple the bandgap reference for very low output noise (down to 50Vrms). The devices utilize CMOS technology to achieve very low operating currents (typically 150A 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. The SC1452 comes in the low profile 10-lead MSOP package.
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 APPLICATIONS *= Cellular telephones *= Palmtop/Laptop computers *= Battery-powered equipment *= Bar code scanners *= SMPS post regulator/dc to dc modules *= High efficiency linear power supplies ORDERING INFORMATION
Part Numbers SC1452XIMSTR
(1)(2)
Package 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.
TYPICAL APPLICATION
U1 3.3V OUT 2.5V OUT 1 2 3 RESET A RESET B 4 5 OUTA OUTB GND RSTA RSTB IN ENA BYP ENB DLYB 10 9 8 7 6 ENABLE OUTPUT B 3.3V IN ENABLE OUTPUT A
SC1452JIMS COUTA 1uF COUTB 1uF CBYP 10nF CDLYB 10nF CIN 1uF
1 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH PROGRAMMABLE RESET
PRELIMINARY - August 7, 2000
SC1452
ABSOLUTE MAXIMUM RATINGS
Parameter Input Supply Voltage Enable Input Voltage Operating Ambient Temperature Range Operating Junction Temperature Range Storage Temperature Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case ESD Rating (Human Body Model) Symbol VIN VEN TA TJ TSTG JA JC ESD Maximum -5 to +7 -5 to +VIN -40 to +85 -40 to +125 -60 to +150 113 42 2 Units V V C C C C/W C/W kV
ELECTRICAL CHARACTERISTICS
Unless specified: TA = 25C, VIN = VOUT + 1V, IOUTA = IOUTB = 1mA, COUT = 1.0 F, VENA = VENB = VIN. Values in bold apply over full operating temperature range.
Parameter IN Input Supply Voltage Quiescent Current
Symbol
Condition
Min
Typ
Max
Units
VIN IQ VENA = 0V, VENB = VIN, IOUTB = 150mA or VENB = 0V, VENA = VIN, IOUTA = 150mA VENA = VENB = VIN, IOUTA = IOUTB = 150mA VENA = VENB = 0V (OFF)
2.5 90
6.5 150 200 150 240 300 0.5 1 2
V A
A
A
OUTA, OUTB Output Voltage VOUT IOUT = 1mA 0mA IOUT = 150mA, VOUT +1V =VIN =5.5V Line Regulation REG(LINE) VOUT + 1V VIN 5.5V, IOUT = 1mA 0.1mA =IOUT =150mA IOUT = 1mA IOUT = 50mA IOUT =150mA Current Limit ILIM 400 -1% -2% 5 VOUT +1% +2% 10 12 Load Regulation REG(LOAD) VD -5 -15 -30 Dropout Voltage 1.1 55 75 120 165 250 300 mA mV mV mV mV mV V
2 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH PROGRAMMABLE RESET
PRELIMINARY - August 7, 2000
SC1452
ELECTRICAL CHARACTERISTICS (Cont.)
Unless specified: TA = 25C, VIN = VOUT + 1V, IOUTA = IOUTB = 1mA, COUT = 1.0 F, VENA = VENB = VIN. Values in bold apply over full operating temperature range.
Parameter OUTA, OUTB (Cont.) Ripple Rejection Output Voltage Noise BYP Start-up Rise Time ENABLE (ENA, ENB) Enable Input Threshold
Symbol
Condition
Min
Typ
Max
Units
PSRR en
f = 120Hz, CBYP = 10nF f = 10Hz to 99kHz, IOUT = 50mA, CBYP = 10nF, COUT = 2.2F
60 50
dB VRMS
tr
CBYP = 10nF
1.5
ms
VIH VIL IEN
1.6 0.4 0.2
V
Enable Input Current RSTA, RSTB Reset Threshold
A
VTH tRSTA tRSTB
(1)
VOUT falling VOUT rising
88 90 30
90 92 50 150
92 94 70 210
%VOUT ms ms %VOUT
Reset A Delay Reset B Delay Reset A, B Output Voltage
VDLYB = 0V ISOURCE = 0.5mA ISINK = 1.2mA
90 80
VOH VOL
0.3
V
DLYB Delay Voltage Threshold Delay Source Current VDLYB IDLYB THI THYST VOUTB < VTH 1.225 1.250 1.275 2.1 3.0 3.9 V A C C
OVER TEMPERATURE PROTECTION High Trip Level Hysteresis 150 20
NOTE: (1) VOHA will be a percentage of VOUTA, and VOHB will be a percentage of VOUTB.
3 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH PROGRAMMABLE RESET
PRELIMINARY - August 7, 2000
SC1452
BLOCK DIAGRAM
4 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH PROGRAMMABLE RESET
PRELIMINARY - August 7, 2000
SC1452
PIN CONFIGURATION
(Top View)
VOLTAGE OPTIONS
Replace X in the part number (SC1452XIMS) by the letter shown below for the corresponding voltage option:
X A B C D E F
MSOP-10
VOUTA (V) 1.8 2.5 2.8 3.0 3.3 3.0 3.0 3.0 3.3 3.3
VOUTB (V) 1.8 2.5 2.8 3.0 3.3 2.5 1.8 2.8 2.5 2.8
G H J
MARKING INFORMATION
K
# = Voltage options (Example: 452F) yyww = Datecode (Example: 0008) XXXX = Lot Number (Example: E01102)
PIN DESCRIPTIONS
Pin # Pin Name 1 2 3 4 5 6 7 8 9 10 OUTA OUTB GND RSTA RSTB DLYB ENB BYP ENA IN Regulator A output. Regulator B output. Ground pin. Power on reset for regulator A. Active low when OUTA is below the reset threshold. Power on reset for regulator B. Active low when OUTB is below the reset threshold. 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. Active high enable pin for output B. CMOS compatible input. Connect to IN if not being used. Bypass pin for bandgap reference. Connect a 10nF capacitor, CBYP, between this pin and ground for low noise operation. Active high enable pin for output A. CMOS compatible input. Connect to IN if not being used. Input pin for both regulators. 5 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 Pin Function
DUAL 150mA LDO REGULATOR WITH PROGRAMMABLE RESET
PRELIMINARY - August 7, 2000
SC1452
APPLICATIONS INFORMATION
Adjusting RSTB Delay Time
voltage is reached. The delay time can be calculated by rearranging the above equation, solving for t:
t RSTB = C DLYB * 1 .25 = 416 ,667 * C DLYB 3 * 10 - 6
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 3A current source turns on, charging CDLYB (if connected). 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:
VDLYB = 3 * 10 -6 * t C DLYB
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. 100
tRSTB (ms)
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 CDLYB (nF)
100
1000
6 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
DUAL 150mA LDO REGULATOR WITH PROGRAMMABLE RESET
PRELIMINARY - August 7, 2000
SC1452
DEVICE OUTLINE - MSOP-10
LAND PATTERN - MSOP- 10 - DRAWING PENDING
ECN 00-1247
7 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

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