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VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The SC1563 is a high performance positive voltage regulator designed for use in applications requiring very low dropout voltage at up to 500 milliamps. Since it has superior dropout characteristics compared to regular LDOs, it can be used to supply 2.5V on motherboards or 2.8V on peripheral cards from the 3.3V supply with no heatsink. Additionally, the SC1563 has a shutdown pin, to further reduce power dissipation while shut down. The SC1563 provides excellent regulation over variations in line, load and temperature. The SC1563 is available as a five terminal fixed or adjustable output voltage device with enable. The device is available in a 5-pin SOT-23 package and an 8-pin MSOP package for higher power dissipation/ lower junction temperature.
FEATURES *= 450mV dropout @ 500mA *= Designed to operate with ceramic capacitors *= Adjustable output from 1.200V to 3.3V *= Multiple output voltage options (all parts also *= *= *= *= *=
adjustable externally using resistors) Over current and over temperature protection Enable pin 1A quiescent current in shutdown Low reverse leakage (output to input) Full industrial temperature range
APPLICATIONS *= Battery powered systems *= Motherboards *= Peripheral cards *= PCMCIA cards ORDERING INFORMATION
DEVICE
(1)(2)(3)
PACKAGE SOT-23-5L MSOP-8
SC1563ISK-X.XTR SC1563IMS-X.XTR
TYPICAL APPLICATION
Internally Preset Output Voltage
U1 5 VIN 1 SHDN C1 VIN SHDN GND 2 3 SC1563ISK-X.X VO 4 VO (X.XV)
Notes: (1) Where -X.X denotes voltage options. Available voltages are: 1.8V, 2.5V, 2.8V, 3.0V, 3.1V and 3.3V. (2) Output voltage can be adjusted using external resistors, see Pin Description. (3) Only available in tape and reel packaging. A reel contains 2500 devices (MSOP-8) or 3000 devices (SOT-23-5L).
Externally Set Output Voltage
U1 5 VIN 1 SHDN C2 C1 VIN SHDN GND 2 SC1563ISK-X.X VO 4 R1 VO
ADJ
ADJ 3
C2 R2
VO
=
1.200 (R1 + R2) R2
Volts
1 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
ABSOLUTE MAXIMUM RATINGS
Parameter Input Voltage Power Dissipation Thermal Resistance Junction to Ambient MSOP-8(1) MSOP-8(2) SOT-23-5L(1) Thermal Resistance Junction to Case MSOP-8 SOT-23-5L Operating Ambient Temperature Range Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering) 10 Sec. ESD Rating Symbol VIN PD JA Maximum 5.5 Internally Limited 206 95 256 39 81 -40 to+85 -40 to 150 -65 to 150 300 2 Units V W C/W
JC
TA
C/W C C C C kV
TJ TSTG TLEAD ESD
Notes: (1) Minimum pad size. (2) 1 square inch of FR-4, double sided, 1oz. minimum copper weight.
ELECTRICAL CHARACTERISTICS
Unless specified: VSHDN = 0V Adjustable Option (VADJ > VTH(ADJ)): VIN = 2.2 to 5.5V and IO = 10A to 500mA Fixed Options (VADJ = GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 500mA Values in bold apply over the full operating temperature range.
Parameter VIN Supply Voltage Range Quiescent Current
Symbol
Test Conditions
Min
Typ
Max
Units
VIN IQ VIN = 3.3V VIN = 5.5V, VSHDN = Open
2.2 100 0.5
5.5 150 2
V A A
VO Output Voltage(1) (Internal Fixed Voltage) Line Regulation
(1) (1)
VO
VIN = VO + 0.7V, IO = 10mA
0.99VO 0.98VO
VO VO 0.035 0.2
1.01VO 1.02VO 0.3 0.4
V
REG(LINE) REG(LOAD)
VIN = (VO + 0.25V) to 5.5V, IOUT = 10mA VIN = VO + 0.7V
% %
Load Regulation
2 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
ELECTRICAL CHARACTERISTICS (Cont.)
Unless specified: VSHDN = 0V Adjustable Option (VADJ > VTH(ADJ)): VIN = 2.2 to 5.5V and IO = 10A to 500mA Fixed Options (VADJ = GND): VIN = (VO + 0.7V) to 5.5V and IO = 0A to 500mA Values in bold apply over the full operating temperature range.
Parameter VO (Cont.) Dropout Voltage(2)
Symbol
Test Conditions
Min
Typ
Max
Units
VD
ILOAD = 2mA ILOAD = 100mA ILOAD = 250mA ILOAD = 500mA
1
5 10
mV
75
100 150
mV
200
300 400
mV
450
550 700
mV
Minimum Load Current Current Limit ADJ Reference Voltage(1)
(3)
IO ICL VREF
VIN = VO + 0.7V 0.50
1
10 1.00
A A
VIN = 2.2V, VADJ = VOUT, IO = 10mA
1.188 1.176
1.200
1.212 1.224
V
Adjust Pin Current
(4)
IADJ VTH(ADJ)
VADJ = VREF 0.10
50 0.20
100 0.40
nA V
Adjust Pin Threshold(5) SHDN Shutdown Pin Current Shutdown Pin Threshold
ISHDN VIH VIL
VSHDN = 0V, VIN = 3.3V VIN = 3.3V VIN = 3.3V 1.8
1
10
A V
0.4
OVER TEMPERATURE PROTECTION High Trip Level Hysteresis THI THYST 165 10 C C
NOTES: (1) Low duty cycle pulse testing with Kelvin connections required. (2) Defined as the input to output differential at which the output voltage drops to 1% below the value measured at a differential of 0.7V. (3) Required to maintain regulation. Voltage set resistors R1 and R2 are usually utilized to meet this requirement. Adjustable versions only. (4) Guaranteed by design. (5) When VADJ exceeds this threshold, the "Sense Select" switch disconnects the internal feedback chain from the error amplifier and connects VADJ instead.
3 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
BLOCK DIAGRAM
PIN CONFIGURATIONS
Top View Top View
SOT-23-5L
MSOP-8
PIN DESCRIPTION
Pin Name ADJ Pin Number SOT-23-5L MSOP-8 3 3 This pin, when grounded, sets the output voltage to that set by the internal feedback resistors. If external feedback resistors are used, the output voltage will be (See Application Circuit): Pin Function
VO
GND VIN VO SHDN 2 5 4 1 5-8 1 4 2
=
1.200 (R1+ R2) R2
Volts
Reference ground. Connect all MSOP-8 GND pins. These pins may be used for heatsinking purposes. Input voltage. For regulation at full load, the input to this pin must be between (VO + 0.7V) to 5.5V. Minimum VIN = 2.2V. This pin is the power output of this device. Shutdown Input. Leaving this pin open turns the regulator off, reducing the quiescent current to a fraction of its operating value (typically <100nA). The device will be enabled if this pin is pulled below 0.4V. Connect to GND if not being used. 4
(c) 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
TYPICAL APPLICATION (Externally Set Output Voltage)
U1 VIN SHDN 5 1 VIN SC1563IS-X.X VO 4
(1)(2)
VO R1
SHDN GND ADJ 2 3
C1 1uF
C2 10uF R2
VO
=
1.200 (R1 + R2) R2
Volts
TYPICAL APPLICATIONS (Internally Set Output Voltage)
U1 VIN SHDN 5 1 VIN SHDN GND 2 SC1563IS-X.X VO 4
(2)
VO (X.XV)
ADJ 3
C1 1uF
C2 10uF
U1 SC1563IMS-X.X VIN SHDN 1 2 3 VO (X.XV) 4 VIN SHDN ADJ VO GND GND GND GND 8 7 6 5
C1 1uF
C2 10uF
Notes: (1) Maximum VO setpoint is 3.3V. (2) This device is designed to operate with ceramic input and output capacitors.
5 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
APPLICATIONS INFORMATION
Introduction The SC1563 is intended for applications such as graphics cards where high current capability and very low dropout voltage are required. It provides a very simple, low cost solution that uses little pcb real estate and typically does not require a heatsink. Additional features include an enable pin to allow for a very low power consumption standby mode, and a fully adjustable output. Component Selection Input capacitor - a 1F ceramic capacitor is recommended. This allows for the device being some distance from any bulk capacitance on the rail. Additionally, input droop due to load transients is reduced, improving load transient response. Additional capacitance may be added if required by the application. Output capacitor - a minimum bulk capacitance of 1F, along with a 0.1F ceramic decoupling capacitor is recommended. Increasing the bulk capacitance will improve the overall transient response. The use of multiple lower value ceramic capacitors in parallel to achieve the desired bulk capacitance will not cause stability issues. Although designed for use with ceramic output capacitors, the SC1563 is extremely tolerant of output capacitor ESR values and thus will also work comfortably with tantalum output capacitors. External voltage selection resistors - the use of 1% resistors, and designing for a current flow 10A is recommended to ensure a well regulated output (thus R2 120k). Thermal Considerations The power dissipation in the SC1563 is approximately equal to the product of the output current and the input to output voltage differential:
PD (VIN - VOUT ) * I O
Thus PD(MAX) = 0.514W. Using this figure, and assuming TA(MAX) = 85C, we can calculate the maximum thermal impedance allowable to maintain TJ 150C:
R TH ( J - A )( MAX ) =
(T
J( MAX )
- TA ( MAX ) )
PD ( MAX )
=
(150 - 70 ) = 156 C / W
0 .514
This should be achievable using pcb copper area to aid in conducting the heat away from the device. Internal ground/power planes and air flow will also assist in removing heat. For higher ambient temperatures additional board copper may be required. Use of the available MSOP-8 package will allow operation at full load where higher input to output voltage differentials exist.
MARKING INFORMATION
MSOP-8
SOT-23-5L
The absolute worst-case dissipation is given by:
PD ( MAX ) = (VIN ( MAX ) - VOUT
( MIN )
)* I
O ( MAX )
+ VIN ( MAX ) * IQ ( MAX )
For a typical scenario, VIN = 3.3V 5%, VOUT = 2.5V and IO = 500mA, therefore: VIN(MAX) = 3.465V, VOUT(MIN) = 2.450V and IQ(MAX) = 1.75mA,
63XX = SC1563, voltage option (example: 6318) yyww = Datecode (example: 0008) XXXX = Lot number (example: E01102)
6 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
DEVICE OUTLINE - SOT-23-5
LAND PATTERN - SOT-23-5
7 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
VERY LOW DROPOUT, LOW QUIESCENT 500mA REGULATOR
PRELIMINARY - September 11, 2000
SC1563
OUTLINE DRAWING - MSOP-8
LAND PATTERN - MSOP-8
ECN00-1343
8 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

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