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150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The SC8863 is a low dropout linear regulator that operates from a +2.5V to +5.5V input range and delivers up to 150mA. A PMOS pass transistor allows the low 110A supply current to remain independent of load, making these devices ideal for battery operated portable equipment such as cellular phones, cordless phones and personal digital assistants. The SC8863 output voltage can be preset or adjusted with an external resistor divider. Other features include low powered shutdown, short circuit protection, thermal shutdown protection and reverse battery protection. The SC8863 comes in the tiny 5 lead SOT-23 package.
FEATURES * Guaranteed 150 mA output current * Fixed or adjustable output * Very small external components * Low 75VRMS output noise * Very low supply current * Thermal overload protection * Reverse battery protection * Low power shutdown * Surface mount packaging (5 pin SOT-23) * Full industrial temperature range APPLICATIONS * Battery Powered Systems * Cellular Telephones * Cordless Telephones * Personal Digital Assistants * Portable Instrumentation * Modems * PCMCIA cards ORDERING INFORMATION
Part Number Package
(1)(2)
BLOCK DIAGRAM
SC8863-XXXCSK
SOT-23-5
Notes: (1) Where -XXX denotes voltage options. Available voltages are: 2.50V (-250), 2.80V (-280), 3.00V (-300), and 3.30 (-330)V. (2) Add suffix `TR' for tape and reel.
ABSOLUTE MAXIMUM RATINGS
Parameter Input Supply Voltage Power Dissipation TA = 70C Thermal Resistance Symbol VIN PD JA JC Maximum -0.6 to +7 571 256 81 -40 to +85 -40 to +150 -65 to +150 +300 1.25 Units V mW C/W C/W C C C C kV 1 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
PIN CONFIGURATION
Operating Ambient Temperature Range Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering) 10 Sec ESD Rating
TA TJ TSTG TLEAD ESD
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
PIN DESCRIPTIONS
Pin # 1 2 3 4 5 Pin Name EN GND IN OUT SET Description Active high enable pin. Connect to VIN if not being used. Ground pin. Can be used for heatsinking if needed. Input pin. Regulator output, sourcing up to 150mA Connecting this pin to ground results in the internally preset value for VOUT. Connecting to an external resistor divider changes VOUT to:
R1 VOUT = 1 .250 * 1 + R2
TYPICAL APPLICATION - INTERNALLY PRESET OUTPUT VOLTAGE
U1 VIN > VOUT + VD(MAX) 3 VIN SC8863 VO 4 VOUT @ IOUT up to 150mA
1 C1 1uF Ceramic
EN
GND 2
SET
5 C2 1uF Ceramic
TYPICAL APPLICATION - EXTERNALLY SET OUTPUT VOLTAGE
U1 VIN > VOUT + VD(MAX) 3 VIN SC8863 VO 4 R1 1 EN GND 2 R2 10k SET 5
(1)
VOUT @ IOUT up to 150mA
C1 1uF Ceramic
C2 2.2uF Ceramic
NOTES: (1) Select R1 and R2 such that the current flowing through them is 10A (i.e. R2 120k). A value of 10k is recommended for R2. Please see Component Selection - Externally Set Output.
2 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
ELECTRICAL CHARACTERISTICS
Unless specified: VIN = 3.6V, VSET = GND, VEN = VIN, TA = 25C. Values in bold apply over full operating ambient temperature range.
Parameter IN Supply Voltage Range Supply Current
Symbol
Conditions
Min
Typ
Max
Units
VIN IQ IOUT = 0mA 50mA IOUT 150mA
2.5 100
5.5 130 160 110 160 200
V A
A
VEN = 0V
0.0001
1 2
A
OUT Output Voltage
(1)
VOUT
IOUT = 1mA 1mA IOUT 150mA, VOUT+1V VIN 5.5V 2.5V VIN 5.5V, SET = OUT, IOUT = 1mA
-2.0% -3.5%
VOUT
+2.0% +3.5%
V
Line Regulation
(1)
REG(LINE)
5
10 12
mV
Load Regulation
(1)
REG(LOAD)
IOUT = 0mA to 50mA IOUT = 0mA to 100mA IOUT = 0mA to 50mA, SET = OUT IOUT = 0mA to 100mA, SET = OUT
-10
-15 -20
mV
-15
-20 -25
mV
-2.5
-7.5 -15.0
mV
-5
-15 -30
mV
Dropout Voltage
(1)(2)
VD
IOUT = 1mA IOUT = 50mA IOUT = 100mA
1.1 55 90 120 110 180 240
mV mV
mV
Current Limit Output Voltage Noise
ILIM en PSRR 10Hz to 99kHz, IOUT = 50mA, COUT = 1F COUT = 100F f 1kHz
150
240 90 75 55
350
mA VRMS dB
Power Supply Rejection Ratio
3 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
ELECTRICAL CHARACTERISTICS (Cont.)
Unless specified: VIN = 3.6V, VSET = GND, VEN = VIN, TA = 25C. Values in bold apply over full operating ambient temperature range.
Parameter EN EN Input Threshold
Symbol
Conditions
Min
Typ
Max
Units
VIH VIL
(3)
1.8 0.4 EN = VIN 0 100 200
V
EN Input Bias Current
IEN
nA
SET Sense/Select Threshold SET Reference Voltage
(1)
VTH VSET IOUT = 1mA 1mA IOUT 150mA, 2.5V VIN 5.5V
20 1.225 1.206
55 1.250
80 1.275 1.294
mV V
SET Input Leakage Current
(3)
ISET
SET = 1.3V
0.015
2.500 5.000
nA
OVER TEMPERATURE PROTECTION High Trip Level Hysteresis THI THYST 170 10 C C
NOTE: (1) Low duty cycle pulse resting with Kelvin corrections required. (2) Defined as the input to output differential at which the output voltage drops 100mV below the value measured at a differential of 2V. (3) Guaranteed by design.
4 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
TYPICAL CHARACTERISTICS
Output Voltage vs. Output Current
2.86 2.85 2.84 2.83 2.82 VOUT (V) VOUT (V) 2.81 2.80 2.79 2.78 2.77 2.76 2.75 2.74 0 25 50 75 IOUT (mA) 100 125 150 VIN = 3.6V TJ = 25C 2.86 2.85 2.84 2.83 2.82 2.81 2.80 2.79 2.78 2.77 2.76 2.75 2.74 -50 -25 0 25 50 75 100 125 TJ (C)
IO = 1mA IO = 50mA IO = 100mA IO = 150mA
Output Voltage vs. Junction Temperature vs. Output Current
VIN = 3.6V
SET Reference Voltage vs. Output Current
1.275 1.270 1.265 1.270 1.260 VSET (V) VSET (V) 1.255 1.250 1.245 1.240 1.230 1.235 1.230 1.225 0 25 50 75 IOUT (mA) 100 125 150 1.220 1.210 1.260 VIN = 3.6V TJ = 25C 1.290 1.280
SET Reference Voltage vs. Junction Temperature vs. Output Current
VIN = 3.6V
IO = 1mA
1.250 1.240
IO = 50mA IO = 100mA IO = 150mA
-50
-25
0
25
50
75
100
125
TJ (C)
Dropout Voltage vs. Output Current vs. Junction Temperature
250 225 200 175 VD (mV) 150 125 100 75 50 25 0 0 25 50 75 IOUT (mA) 100 125 150 0 -50 -25
-40C 25C 125C
Line Regulation vs. Junction Temperature
12 10 8 6 4 2 VIN = 2.5V to 5.5V SET = OUT IOUT = 1mA
SET = GND
REG(LINE) (mV)
0
25 TJ (C)
50
75
100
125
5 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
TYPICAL CHARACTERISTICS (Cont.)
Load Regulation (SET = GND) vs. Junction Temperature
50 45 40 REG(LOAD) (mV) 35 30 25 20 15 5.0 10 5 0 -50 -25 0 25 TJ (C) 50 75 100 125 IOUT = 0mA to 50mA 2.5 0.0 -50 -25 0 25 TJ (C) 50 75 100 125 IOUT = 0mA to 50mA IOUT = 0mA to 100mA VIN = 3.6V SET = GND IOUT = 0mA to 150mA REG(LOAD) (mV) 20.0 17.5 15.0 12.5 10.0 7.5 IOUT = 0mA to 100mA VIN = 3.6V SET = OUT IOUT = 0mA to 150mA
Load Regulation (SET = OUT) vs. Junction Temperature
Supply Current vs. Output Current
120 110 100 90 80 IQ (A) 60 50 40 30 20 10 0 0 VIN = 3.6V TJ = 25C 25 50 75 IOUT (mA) 100 125 150 25 0 -50 -25 IQ (A) 70 100 75 50 125 150 VIN = 3.6V IOUT = 150mA
Supply Current vs. Junction Temperature
0
25 TJ (C)
50
75
100
125
Current Limit vs. Junction Temperature
350 VIN = 3.6V 300 250 VIH, VIL (V) ILIM (mA) 200 150 100 50 0 -50 -25 0 25 TJ (C) 50 75 100 125 1.8 1.6 1.4 1.2 1.0 2.0 VIN = 3.6V
Enable Input Threshold vs. Junction Temperature
VIH
VIL 0.8 0.6 0.4 -50 -25 0 25 TJ (C) 50 75 100 125
6 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
TYPICAL CHARACTERISTICS (Cont.)
Sense/Select Threshold vs. Junction Temperature
80 VIN = 3.6V 70 60 VTH (mV) 50 40 30 COUT = 100F 20 -50 -25 0 25 TJ (C) 50 75 100 125 0.01 0.1 1 f (kHz) 10 100 1 COUT = 1F 10 SC8863-2.8 VIN = 3.6V IOUT = 50mA TJ = 25C en (V/Hz)
Output Spectral Noise Density vs. Frequency
0.1
APPLICATIONS INFORMATION
Theory Of Operation The SC8863 is intended for applications where very low dropout voltage, low supply current and low output noise are critical. It provides a very simple, low cost solution that uses very little pcb real estate. Fixed output voltage options require the use of only two external capacitors for operation. Each voltage option has both fixed and adjustable output voltage modes. Grounding the SET pin (pulling it below the Sense/Select threshold of 55mV) will connect the internal resistor divider to the error amplifier resulting with the internally preset output voltage. If SET is pulled above this threshold, then the Sense/ Select switch will connect the SET pin to the error amplifier. The output will be regulated such that the voltage at SET will equal VSET, the SET reference voltage (typically 1.250V). An active high enable pin (EN) is provided to allow the customer to shut down the part and enter an extremely low power Off-state. A logic Low signal will reduce the supply current to 0.1nA. Component Selection - General Output capacitor - Semtech recommends a minimum capacitance of 1F at the output with an equivalent series resistance (ESR) of <1 over temperature. Ceramic capacitors are ideal for this application. Increas-
ing the bulk capacitance will further reduce output noise and improve the overall transient response. Input capacitor - Semtech recommends the use of a 1F ceramic capacitor at the input. 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. Component Selection - Externally Set Output Please refer to Figure 1 below. The output voltage can be externally adjusted anywhere within the range from 1.25V to (VIN(MIN) - VD(MAX)). The output voltage will be in accordance with the following equation:
R1 VO = 1 .250 * 1 + R2
1% tolerance resistors are recommended. The values of R1 and R2 should be selected such that the current flow through them is 10A (thus R2 120k). At high input voltages and/or high output currents, staU1 3 VIN SC8863 VO 4 R1 1 EN GND 2 R2 10k SET 5
C1 1uF Ceramic
C2 2.2uF Ceramic
Figure 1: Externally set output 7 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000 bility may be improved by increasing C2 to 2.2F and reducing R2 to 10k. See "Component Selection General" for input capacitor requirements. Thermal Considerations The worst-case power dissipation for this part is given by:
PD ( MAX ) = (VIN (MAX ) - VO (MIN ) ) * I O ( MAX ) + VIN ( MAX ) * IQ ( MAX ) PD ( MAX ) = (VIN (MAX ) - VO (MIN ) ) * IO ( MAX )
SC8863
The junction temperature can be further reduced by the use of larger trace widths, and connecting pcb copper area to the GND pin (pin 2), which connectes directly to the device substrate. Adding approximately one square inch of pcb copper to pin 2 will reduce TH(J-A) to approximately 130C/W and TJ(MAX) to approximately 110C, for example. Lower junction temperatures improve overall output voltage accuracy. A sample pcb layout for the Internally Preset Output Voltage circuit on page 2 is shown in Figure 2 below. 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. See Figure 2 below for a sample layout. 1) Attaching the part to a larger copper footprint will enable better heat transfer from the device, especially on PCBs where there are internal ground and power planes. 2) Place the input and output capacitors (and the capacitor from OUT to SET for adjustable applications) close to the device for optimal transient response and device behaviour. 3) Connect all ground connections directly to the ground plane. If there is no ground plane, connect to a common local ground point before connecting to board ground.
For all practical purposes, it can be reduced to:
Looking at a typical application: VIN(MAX) = 4.2V VO = 3V - 3.5% worst-case IO = 150mA TA = 85C
PD ( MAX ) = (4 . 2 - 2 . 895 ) * 0 . 150 = 196 mW
Using this figure, we can calculate the maximum thermal impedance allowable to maintain TJ 150C:
( J - A )( MAX ) =
(T
J ( MAX )
- TA ( MAX ) )
PD ( MAX )
=
(150 - 85 ) = 332 C / W
0 .196
With the standard SOT-23-5 Land Pattern shown at the end of this datasheet, and minimum trace widths, the thermal impedance junction to ambient for SC8863 is 256C/W. Thus with no additional heatsinking, TJ(MAX) = 135C.
Top Copper
Top Silk Screen
Figure 2: Suggested pcb layout based upon internally preset output voltage application on page 2. NOTES: (1) All vias go to the ground plane. (2) Copper area on pin 2 is recommended, but not required. Connect to the ground plane with a via or vias.
8 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ULTRA LOW DROPOUT, LOW NOISE REGULATOR
March 1, 2000
SC8863
DEVICE OUTLINE - SOT23-5
LAND PATTERN - SOT23-5
ECN 00-915
9 (c) 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

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