MICROCHIP TC1303B

TC1303B
500 mA Synchronous Buck Regulator,
+ 300 mA LDO with Power-Good Output
Features
Description
• Dual-Output Regulator (500 mA Buck Regulator
and 300 mA Low-Dropout Regulator)
• Power-Good Output with 300 ms Delay
• Total Device Quiescent Current = 65 µA, Typ.
• Independent Shutdown for Buck and LDO
Outputs
• Both Outputs Internally Compensated
• Synchronous Buck Regulator:
- Over 90% Typical Efficiency
- 2.0 MHz Fixed Frequency PWM
(Heavy Load)
- Low Output Noise
- Automatic PWM to PFM mode transition
- Adjustable (0.8V to 4.5V) and Standard Fixed
Output Voltages (0.8V, 1.2V, 1.5V, 1.8V, 2.5V,
3.3V)
• Low-Dropout Regulator:
- Low-Dropout Voltage = 137 mV Typ. @
200 mA
- Standard Fixed Output Voltages
(1.5V, 1.8V, 2.5V, 3.3V)
• Power-Good Function:
- Monitors LDO Output Function (TC1303B)
- 300 ms Delay Used for Processor Reset
• Small 10-pin 3X3 DFN or MSOP Package
Options
• Operating Junction Temperature Range:
- -40°C to +125°C
• Undervoltage Lockout (UVLO)
• Output Short Circuit Protection
• Overtemperature Protection
The TC1303B combines a 500 mA synchronous buck
regulator and 300 mA Low-Dropout Regulator (LDO)
with a power-good monitor to provide a highly
integrated solution for devices that require multiple
supply voltages. The unique combination of an
integrated buck switching regulator and low-dropout
linear regulator provides the lowest system cost for
dual-output voltage applications that require one lower
processor core voltage and one higher bias voltage.
Applications
Package Type
•
•
•
•
•
Cellular Phones
Portable Computers
USB Powered Devices
Handheld Medical Instruments
Organizers and PDAs
The 500 mA synchronous buck regulator switches at a
fixed frequency of 2.0 MHz when the load is heavy
providing a low noise, small-size solution. When the
load on the buck output is reduced to light levels, it
changes operation to a Pulse Frequency Modulation
(PFM) mode to minimize quiescent current draw from
the battery. No intervention is necessary for smooth
transition from one mode to another.
The LDO provides a 300 mA auxiliary output that
requires a single 1 µF ceramic output capacitor,
minimizing board area and cost. The typical dropout
voltage for the LDO output is 137 mV for a 200 mA
load.
For the TC1303B, the power-good output logic level is
based on the regulation of the LDO output only. The
buck regulator can be turned on and off without affecting
the power-good signal.
The TC1303B is available in either the 10-pin DFN or
MSOP package.
Additional protection features include: UVLO,
overtemperature and overcurrent protection on both
outputs.
For a complete listing of TC1303B standard parts, consult your Microchip representative.
10-Lead DFN
SHDN2 1
VIN2 2
VOUT2 3
PG 4
AGND 5
© 2005 Microchip Technology Inc.
10 PGND
9 LX
8 VIN1
7 SHDN1
6 VFB1/VOUT1
10-Lead MSOP
SHDN2 1
VIN2 2
VOUT2 3
PG 4
AGND 5
10 PGND
9 LX
8
VIN1
7 SHDN1
6 VFB1/VOUT1
DS21949A-page 1
TC1303B
Functional Block Diagram
UVLO
Undervoltage Lockout
(UVLO)
VREF
Synchronous BUCK Regulator
VIN1
PDRV
VIN2
LX
SHDN1
Driver
Control
NDRV
PGND
PGND
PGND
AGND
VOUT1/VFB1
PG
TC1303B
PG Generator with Delay
VREF
UVLO
VOUT2
LDO
SHDN2
DS21949A-page 2
AGND
© 2005 Microchip Technology Inc.
TC1303B
Typical Application Circuits
TC1303B
Fixed Output Application
10-Lead MSOP
4.7µH
VIN
8
2.7V to 4.2V
4.7 µF
2
VIN1
VIN2
LX
7
SHDN1
1
SHDN2
VOUT2
4
PG
4.7 µF
PGND 10
VOUT1
AGND
VOUT1
1.5V @ 500 mA
9
6
3
5
VOUT2
1 µF
2.5V @ 300 mA
Processor
RESET
TC1303B
Adjustable Output Application
10-Lead DFN
4.7 µH
Input
Voltage
4.5V to 5.5V
*Optional
Capacitor
VIN2
4.7 µF
1.0 µF
8
VIN1
2
VIN2
7
SHDN1
1
SHDN2
VOUT2
PG
AGND
VOUT1
9
PGND 10
VOUT1 6
4
Processor
RESET
LX
4.7 µF
VOUT2
3
5
Note
200 kΩ
1 µF
3.3V @
300 mA
4.99 kΩ
2.1V @
500 mA
33 pF
121 kΩ
Note: Connect DFN package exposed pad to AGND.
© 2005 Microchip Technology Inc.
DS21949A-page 3
TC1303B
1.0
ELECTRICAL
CHARACTERISTICS
† Notice: Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device. This is
a stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied.
Exposure to maximum rating conditions for extended periods
may affect device reliability.
Absolute Maximum Ratings †
VIN - AGND ......................................................................6.0V
All Other I/O .............................. (AGND - 0.3V) to (VIN + 0.3V)
LX to PGND .............................................. -0.3V to (VIN + 0.3V)
PGND to AGND................................................... -0.3V to +0.3V
Output Short Circuit Current ................................. Continuous
Power Dissipation (Note 7) ..........................Internally Limited
Storage temperature .....................................-65°C to +150°C
Ambient Temp. with Power Applied.................-40°C to +85°C
Operating Junction Temperature...................-40°C to +125°C
ESD protection on all pins (HBM) ....................................... 3 kV
DC CHARACTERISTICS
Electrical Characteristics: VIN1 =VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1µF, L = 4.7 µH, VOUT1 (ADJ) = 1.8V,
IOUT1 = 100 ma, IOUT2 = 0.1 mA TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C.
Parameters
Sym
Min
Typ
Max
Units
Conditions
Input/Output Characteristics
Input Voltage
VIN
2.7
—
5.5
V
Maximum Output Current
IOUT1_MAX
500
—
—
mA
Maximum Output Current
IOUT2_MAX
300
—
—
mA
Note 1
IIN_SHDN
—
0.05
1
µA
SHDN1 = SHDN2 = GND
IQ
—
65.0
110
µA
SHDN1 = SHDN2 = VIN2
IOUT1 = 0 mA, IOUT2 = 0 mA
Synchronous Buck IQ
—
38
—
µA
SHDN1 = VIN, SHDN2 = GND
LDO IQ + Voltage Monitor IQ
—
46
—
µA
SHDN1 = GND, SHDN2 = VIN2
Shutdown Current
Combined VIN1 and VIN2 Current
TC1303B Operating IQ
Note 1, Note 2, Note 8
Note 1
Shutdown/UVLO/Thermal Shutdown Characteristics
SHDN1,SHDN2,
Logic Input Voltage Low
VIL
—
—
15
%VIN
VIN1 =VIN2 = 2.7V to 5.5V
SHDN1,SHDN2,
Logic Input Voltage High
VIH
45
—
—
%VIN
VIN1 =VIN2 = 2.7V to 5.5V
SHDN1,SHDN2,
Input Leakage Current
IIN
-1.0
±0.01
1.0
µA
VIN1 =VIN2 = 2.7V to 5.5V
SHDNX = GND
SHDNY = VIN
Note 6, Note 7
Thermal Shutdown
Thermal Shutdown Hysteresis
Undervoltage Lockout
(VOUT1 and VOUT2)
Undervoltage Lockout Hysteresis
Note 1:
2:
3:
4:
5:
6:
7:
8:
TSHD
—
165
—
°C
TSHD-HYS
—
10
—
°C
UVLO
2.4
2.55
2.7
V
UVLO-HYS
—
200
—
mV
VIN1 Falling
The Minimum VIN has to meet two conditions: VIN ≥ 2.7V and VIN ≥ VRX + VDROPOUT, VRX = VR1 or VR2.
VRX is the regulator output voltage setting.
TCVOUT2 = ((VOUT2max – VOUT2min) * 106)/(VOUT2 * DT).
Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested
over a load range from 0.1 mA to the maximum specified output current.
Dropout voltage is defined as the input to output voltage differential at which the output voltage drops 2% below its
nominal value measured at a 1V differential.
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e. TA, TJ, θJA). Exceeding the maximum allowable power
dissipation causes the device to initiate thermal shutdown.
The integrated MOSFET switches have an integral diode from the LX pin to VIN, and from LX to PGND. In cases where
these diodes are forward-biased, the package power dissipation limits must be adhered to. Thermal protection is not
able to limit the junction temperature for these cases.
VIN1 and VIN2 are supplied by the same input source.
DS21949A-page 4
© 2005 Microchip Technology Inc.
TC1303B
DC CHARACTERISTICS (CONTINUED)
Electrical Characteristics: VIN1 =VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1µF, L = 4.7 µH, VOUT1 (ADJ) = 1.8V,
IOUT1 = 100 ma, IOUT2 = 0.1 mA TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C.
Parameters
Sym
Min
Typ
Max
Units
Conditions
Synchronous Buck Regulator (VOUT1)
Adjustable Output Voltage Range
VOUT1
0.8
—
4.5
V
Adjustable Reference Feedback
Voltage (VFB1)
VFB1
0.78
0.8
0.82
V
Feedback Input Bias Current
(IFB1)
IVFB1
—
-1.5
—
nA
Output Voltage Tolerance Fixed
(VOUT1)
VOUT1
-2.5
±0.3
+2.5
%
Line Regulation (VOUT1)
VLINE-REG
—
0.2
—
%/V
Load Regulation (VOUT1)
VLOAD-REG
—
0.2
—
%
Dropout Voltage VOUT1
VIN – VOUT1
—
280
—
mV
FOSC
1.6
2.0
2.4
MHz
TSS
—
0.5
—
ms
TR = 10% to 90%
RDSon P-CHANNEL
RDSon-P
—
450
650
mΩ
IP=100 mA
RDSon N-CHANNEL
RDSon-N
—
450
650
mΩ
IN=100 mA
ILX
-1.0
±0.01
1.0
μA
SHDN = 0V, VIN = 5.5V, LX = 0V,
LX = 5.5V
+ILX(MAX)
—
700
—
mA
VOUT2
-2.5
±0.3
+2.5
%
Internal Oscillator Frequency
Start Up Time
LX Pin Leakage Current
Positive Current Limit Threshold
Note 2
VIN =VR+1V to 5.5V,
ILOAD = 100 mA
VIN = VR + 1.5V, ILOAD = 100 mA to
500 mA (Note 1)
IOUT1 = 500 mA, VOUT1 = 3.3V
(Note 5)
LDO Output (VOUT2)
Output Voltage Tolerance (VOUT2)
Note 2
Temperature Coefficient
TCVOUT
—
25
—
ppm/°C
Line Regulation
ΔVOUT2/
ΔVIN
-0.2
±0.02
+0.2
%/V
Load Regulation, VOUT2 ≥ 2.5V
ΔVOUT2/
IOUT2
-0.75
0.1
+0.75
%
IOUT2 = 0.1 mA to 300 mA (Note 4)
Load Regulation, VOUT2 < 2.5V
ΔVOUT2/
IOUT2
-0.90
0.1
+0.90
%
IOUT2 = 0.1 mA to 300 mA (Note 4)
Dropout Voltage VOUT2 > 2.5V
VIN – VOUT2
—
137
205
300
500
mV
IOUT2 = 200 mA (Note 5)
IOUT2 = 300 mA
PSRR
—
62
—
dB
f ≤ 100 Hz, IOUT1 = IOUT2 = 50 mA,
CIN = 0 µF
eN
—
1.8
—
µV/(Hz)½
IOUTsc2
—
240
—
mA
Power Supply Rejection Ratio
Output Noise
Output Short Circuit Current
(Average)
Note 1:
2:
3:
4:
5:
6:
7:
8:
Note 3
(VR+1V) ≤ VIN ≤ 5.5V
f ≤ 1 kHz, IOUT2 = 50 mA,
SHDN1 = GND
RLOAD2 ≤ 1Ω
The Minimum VIN has to meet two conditions: VIN ≥ 2.7V and VIN ≥ VRX + VDROPOUT, VRX = VR1 or VR2.
VRX is the regulator output voltage setting.
TCVOUT2 = ((VOUT2max – VOUT2min) * 106)/(VOUT2 * DT).
Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested
over a load range from 0.1 mA to the maximum specified output current.
Dropout voltage is defined as the input to output voltage differential at which the output voltage drops 2% below its
nominal value measured at a 1V differential.
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e. TA, TJ, θJA). Exceeding the maximum allowable power
dissipation causes the device to initiate thermal shutdown.
The integrated MOSFET switches have an integral diode from the LX pin to VIN, and from LX to PGND. In cases where
these diodes are forward-biased, the package power dissipation limits must be adhered to. Thermal protection is not
able to limit the junction temperature for these cases.
VIN1 and VIN2 are supplied by the same input source.
© 2005 Microchip Technology Inc.
DS21949A-page 5
TC1303B
DC CHARACTERISTICS (CONTINUED)
Electrical Characteristics: VIN1 =VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1µF, L = 4.7 µH, VOUT1 (ADJ) = 1.8V,
IOUT1 = 100 ma, IOUT2 = 0.1 mA TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C.
Parameters
Sym
Min
Typ
Max
Units
tWK
—
31
100
µs
IOUT1 = IOUT2 = 50 mA
tS
—
100
—
µs
IOUT1 = IOUT2 = 50 mA
Voltage Range PG
VPG
1.0
1.2
—
5.5
5.5
V
TA = 0°C to +70°C
TA = -40°C to +85°C
VIN ≤ 2.7 ISINK = 100 µA
PG Threshold High
(VOUT1 or VOUT2)
VTH_H
—
94
96
% of
VOUTX
On Rising VOUT1 or VOUT2
VOUTX = VOUT1 or VOUT2
PG Threshold Low
(VOUT1 or VOUT2)
VTH_L
89
92
—
% of
VOUTX
On Falling VOUT1 or VOUT2
VOUTX = VOUT1 or VOUT2
PG Threshold Hysteresis
(VOUT1 and VOUT2)
VTH_HYS
—
2
—
% of
VOUTX
VOUTX = VOUT1 or VOUT2
PG Threshold Tempco
ΔVTH/ΔT
—
30
—
ppm/°C
PG Delay
tRPD
—
165
—
µs
VOUT1 or VOUT2 = (VTH + 100 mV)
to (VTH - 100 mV)
PG Active Time-out Period
tRPU
140
262
560
ms
VOUT1 or VOUT2 = VTH - 100 mV
to VTH + 100 mV,
ISINK = 1.2 mA
PG Output Voltage Low
PG_VOL
—
—
0.2
V
VOUT1 or VOUT2 = VTH - 100 mV,
IPG= 1.2 mA VIN2 > 2.7V
IPG = 100 µA, 1.0V < VIN2 < 2.7V
PG Output Voltage High
PG_VOH
0.9* VOUT2
—
—
V
VOUT1 or VOUT2 = VTH + 100 mV
VOUT2 ≥ 1.8V, IPG = - 500 µA
VOUT2 < 1.8V,IPG = - 300 µA
Wake-Up Time (From SHDN2
mode), (VOUT2)
Settling Time (From SHDN2
mode), (VOUT2)
Conditions
Power-Good
Note 1:
2:
3:
4:
5:
6:
7:
8:
The Minimum VIN has to meet two conditions: VIN ≥ 2.7V and VIN ≥ VRX + VDROPOUT, VRX = VR1 or VR2.
VRX is the regulator output voltage setting.
TCVOUT2 = ((VOUT2max – VOUT2min) * 106)/(VOUT2 * DT).
Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested
over a load range from 0.1 mA to the maximum specified output current.
Dropout voltage is defined as the input to output voltage differential at which the output voltage drops 2% below its
nominal value measured at a 1V differential.
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e. TA, TJ, θJA). Exceeding the maximum allowable power
dissipation causes the device to initiate thermal shutdown.
The integrated MOSFET switches have an integral diode from the LX pin to VIN, and from LX to PGND. In cases where
these diodes are forward-biased, the package power dissipation limits must be adhered to. Thermal protection is not
able to limit the junction temperature for these cases.
VIN1 and VIN2 are supplied by the same input source.
DS21949A-page 6
© 2005 Microchip Technology Inc.
TC1303B
TEMPERATURE SPECIFICATIONS
Electrical Specifications: Unless otherwise indicated, all limits are specified for: VIN = +2.7V to +5.5V
Parameters
Sym
Min
Typ
Max
Units
Conditions
Operating Junction Temperature
Range
TJ
-40
—
+125
°C
Storage Temperature Range
TA
-65
—
+150
°C
Maximum Junction Temperature
TJ
—
—
+150
°C
Thermal Resistance, 10L-DFN
θJA
—
41
—
°C/W Typical 4-layer board with
Internal Ground Plane and 2 Vias
in Thermal Pad
Thermal Resistance, 10L-MSOP
θJA
—
113
—
°C/W Typical 4-layer board with
Internal Ground Plane
Temperature Ranges
Steady state
Transient
Thermal Package Resistances
© 2005 Microchip Technology Inc.
DS21949A-page 7
TC1303B
2.0
TYPICAL PERFORMANCE CURVES
Note:
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
IQ Switcher and LDO (µA)
80
IOUT1 = IOUT2 = 0 mA
SHDN1 = VIN2
SHDN2 = VIN2
76
VIN = 5.5V
72
VIN = 4.2V
68
64
VIN = 3.6V
VOUT1 Efficiency (%)
Note: Unless otherwise indicated, VIN1 = VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1 µF, L = 4.7 µH,
VOUT1 (ADJ) = 1.8V, TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C. TA = +25°C. Adjustable or fixed
output voltage options can be used to generate the Typical Performance Characteristics.
60
-40 -25 -10
5
100
95
90
85
80
75
70
65
60
55
50
20 35 50 65 80 95 110 125
IOUT1 = 250 mA
IOUT1 = 500 mA
2.7
3.05
3.4
IOUT1 = 0 mA
SHDN1 = VIN2
SHDN2 = AGND
VIN = 5.5V
50
45
40
VIN = 4.2V
VIN = 3.6V
35
5
90
85
VIN1 = 3.6V
80
VIN1 = 4.2V
75
VIN1 = 3.0V
0.104
0.203
VIN = 3.6V
40
35
SHDN1 = AGND
SHDN2 = VIN2
30
VOUT1 Efficiency(%)
IQ LDO (µA)
VIN = 4.2V
0.401
0.5
FIGURE 2-5:
VOUT1 Output Efficiency vs.
IOUT1 (VOUT1 = 1.2V).
95
45
0.302
100
50
5.5
IOUT1 (A)
VIN = 5.5V
IOUT2 = 0 mA
5.15
SHDN1 = VIN2
SHDN2 = AGND
Ambient Temperature (°C)
55
4.8
95
70
0.005
20 35 50 65 80 95 110 125
FIGURE 2-2:
IQ Switcher Current vs.
Ambient Temperature.
4.45
100
30
-40 -25 -10
4.1
FIGURE 2-4:
VOUT1 Output Efficiency vs.
Input Voltage (VOUT1 = 1.2V).
VOUT1 Efficiency(%)
IQ Switcher (µA)
55
3.75
Input Voltage (V)
Ambient Temperature (°C)
FIGURE 2-1:
IQ Switcher and LDO
Current vs. Ambient Temperature.
SHDN1 = VIN2
SHDN2 = AGND
IOUT1 = 100 mA
SHDN1 = VIN2
SHDN2 = AGND
IOUT1 = 100 mA
90
IOUT1 = 250 mA
85
80
IOUT1 = 500 mA
75
70
65
60
-40 -25 -10
5
20 35 50 65 80 95 110 125
Ambient Temperature (°C)
FIGURE 2-3:
Temperature.
DS21949A-page 8
IQ LDO Current vs. Ambient
2.7
3.05
3.4
3.75
4.1
4.45
4.8
5.15
5.5
Input Voltage (V)
FIGURE 2-6:
VOUT1 Output Efficiency vs.
Input Voltage (VOUT1 = 1.8V).
© 2005 Microchip Technology Inc.
TC1303B
Note: Unless otherwise indicated, VIN1 = VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1 µF, L = 4.7 µH,
VOUT1 (ADJ) = 1.8V, TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C. TA = +25°C. Adjustable or fixed
output voltage options can be used to generate the Typical Performance Characteristics.
1.21
SHDN1 = VIN2
SHDN2 = AGND
VIN = 3.0V
95
90
VIN = 4.2V
85
80
0.104
0.203
0.302
0.401
VIN1 = 3.6V
1.202
1.198
1.194
VIN = 3.6V
75
0.005
SHDN1 = VIN2
SHDN2 = AGND
1.206
VOUT1 (V)
VOUT1 Efficiency(%)
100
1.19
0.005
0.5
0.104
IOUT1 (A)
FIGURE 2-10:
(VOUT1 = 1.2V).
IOUT1 = 100 mA
IOUT1 = 250 mA
88
IOUT1 = 500 mA
1.81
1.805
1.8
1.795
80
3.60
3.92
4.23
4.55
4.87
5.18
1.79
0.005
5.50
0.104
0.203
0.302
FIGURE 2-8:
VOUT1 Output Efficiency vs.
Input Voltage (VOUT1 = 3.3V).
FIGURE 2-11:
(VOUT1 = 1.8V).
3.4
VIN1 = 3.6V
SHDN1 = VIN2
SHDN2 = AGND
3.36
VIN1 = 4.2V
75
VOUT1 (V)
90
SHDN1 = VIN2
SHDN2 = AGND
80
0.5
VOUT1 vs. IOUT1
95
85
0.401
IOUT1 (A)
Input Voltage (V)
VOUT1 Efficiency (%)
0.5
SHDN1 = VIN2
SHDN2 = AGND
VIN1 = 3.6V
1.815
84
100
0.401
VOUT1 vs. IOUT1
1.82
SHDN1 = VIN2
SHDN2 = AGND
VOUT1 (V)
VOUT1 Efficiency (%)
100
92
0.302
IOUT1 (A)
FIGURE 2-7:
VOUT1 Output Efficiency vs.
IOUT1 (VOUT1 = 1.8V).
96
0.203
VIN1 = 5.5V
70
VIN1 = 4.2V
3.32
3.28
3.24
65
60
0.005
0.104
0.203
0.302
0.401
0.5
3.2
0.005
0.104
IOUT1 (A)
FIGURE 2-9:
VOUT1 Output Efficiency vs.
IOUT1 (VOUT1 = 3.3V).
© 2005 Microchip Technology Inc.
0.203
0.302
0.401
0.5
IOUT1 (A)
FIGURE 2-12:
(VOUT1 = 3.3V).
VOUT1 vs. IOUT1
DS21949A-page 9
TC1303B
Note: Unless otherwise indicated, VIN1 = VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1 µF, L = 4.7 µH,
SHDN1 = VIN2
SHDN2 = AGND
2.10
2.05
2.00
1.95
1.90
4.7
5.1
0.35
P-Channel
0.3
5.5
3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5
Input Voltage (V)
Input Voltage (V)
SHDN1 = VIN2
SHDN2 = AGND
1.96
1.94
1.92
125
110
95
80
65
50
35
5
20
-10
-25
-40
1.90
0.55
P-Channel
0.5
N-Channel
0.45
0.4
0.35
0.3
-40 -25 -10
0.805
0.800
0.795
125
110
95
80
65
50
35
20
5
-10
-25
-40
0.790
Ambient Temperature (°C)
FIGURE 2-15:
VOUT1 Adjustable Feedback
Voltage vs. Ambient Temperature.
DS21949A-page 10
SHDN1 = VIN2
SHDN2 = AGND
0.35
0.3
0.25
0.2
VOUT1 = 3.3V
IOUT1 = 500 mA
0.15
0.1
-25
VIN1 = 3.6V
0.4
-40
VOUT1 FB Voltage (V)
SHDN1 = VIN2
SHDN2 = AGND
0.810
20 35 50 65 80 95 110 125
FIGURE 2-17:
Buck Regulator Switch
Resistance vs. Ambient Temperature.
VOUT1 Dropout Voltage (V)
FIGURE 2-14:
VOUT1 Switching Frequency
vs. Ambient Temperature.
0.815
5
Ambient Temperature (°C)
Ambient Temperature (°C)
0.820
SHDN1 = VIN2
SHDN2 = AGND
VIN1 = 3.6V
0.6
125
1.98
0.65
VOUT1 Switch Resistance
5
VOUT1 Frequency (MHz)
2.00
FIGURE 2-16:
vs. Input Voltage.
VOUT1 Switch Resistance (Ω)
VOUT1 Switching Frequency
-10
FIGURE 2-13:
vs. Input Voltage.
110
4.3
N-Channel
0.4
95
3.9
0.45
80
3.5
0.5
65
3.1
SHDN1 = VIN2
SHDN2 = AGND
TA = 25 °C
50
2.7
0.55
35
2.15
0.6
20
VOUT1 Frequency (MHz)
2.20
VOUT1 Switch Resistance (Ω)
VOUT1 (ADJ) = 1.8V, TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C. TA = +25°C. Adjustable or fixed
output voltage options can be used to generate the Typical Performance Characteristics.
Ambient Temperature (°C)
FIGURE 2-18:
VOUT1 Dropout Voltage vs.
Ambient Temperature.
2005 Microchip Technology Inc.
TC1303B
Note: Unless otherwise indicated, VIN1 = VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1 µF, L = 4.7 µH,
VOUT1 (ADJ) = 1.8V, TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C. TA = +25°C. Adjustable or fixed
output voltage options can be used to generate the Typical Performance Characteristics.
VOUT2 Output Voltage (V)
1.802
IOUT2 = 150 mA
1.800
SHDN1 = AGND
SHDN2 = VIN2
TA = + 85°C
1.798
TA = + 25°C
1.796
TA = - 40°C
1.794
1.792
2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5
Input Voltage (V)
FIGURE 2-19:
VOUT1 and VOUT2 Heavy
Load Switching Waveforms vs. Time.
FIGURE 2-22:
VOUT2 Output Voltage vs.
Input Voltage (VOUT2 = 1.8V).
VOUT2 Output Voltage (V)
2.508
SHDN1 = AGND
SHDN2 = VIN2
IOUT2 = 150 mA
2.506
TA = + 85°C
2.504
2.502
TA = + 25°C
2.500
2.498
TA = - 40°C
2.496
3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5
Input Voltage (V)
FIGURE 2-20:
VOUT1 and VOUT2 Light
Load Switching Waveforms vs. Time.
IOUT2 = 150 mA
3.298
TA = + 85°C
1.49
1.488
TA = + 25°C
SHDN1 = AGND
SHDN2 = VIN2
1.486
TA = - 40°C
1.484
1.482
2.7
3.05
3.4
3.75
4.1
4.45
4.8
5.15
5.5
Input Voltage (V)
FIGURE 2-21:
VOUT2 Output Voltage vs.
Input Voltage (VOUT2 = 1.5V).
© 2005 Microchip Technology Inc.
VOUT2 Output Voltage (V)
1.492
VOUT2 Output Voltage(V)
FIGURE 2-23:
VOUT2 Output Voltage vs.
Input Voltage (VOUT2 = 2.5V).
SHDN1 = AGND
SHDN2 = VIN2
IOUT2 = 150 mA
3.297
TA = + 85°C
3.296
3.295
TA = + 25°C
3.294
TA = - 40°C
3.293
3.292
3.60
3.92
4.23
4.55
4.87
5.18
5.50
Input Voltage (V)
FIGURE 2-24:
VOUT2 Output Voltage vs.
Input Voltage (VOUT2 = 3.3V).
DS21949A-page 11
TC1303B
SHDN1 = AGND
SHDN2 = VIN2
0.25
IOUT2 = 300 mA
0.20
IOUT2 = 200 mA
0.15
0.10
0.05
0.1
VIN2 = 3.6V
-0.1
-0.2
VOUT2 = 2.6V
VOUT2 = 1.5V
-0.3
VOUT2 Dropout Voltage (V)
0.3
SHDN1 = AGND
SHDN2 = VIN2
0.2
IOUT2 = 300 mA
0.1
IOUT2 = 200 mA
125
110
95
80
65
50
35
20
Ambient Temperature (°C)
FIGURE 2-28:
VOUT2 Load Regulation vs.
Ambient Temperature.
PG Active Delay Time (ms)
FIGURE 2-25:
VOUT2 Dropout Voltage vs.
Ambient Temperature (VOUT2 = 2.5V).
5
-10
-25
125
110
95
80
65
50
35
5
20
-10
-25
-40
-0.4
Ambient Temperature (°C)
350
VIN = 3.6V
325
SHDN1 = VIN2
SHDN2 = VIN2
300
275
250
225
200
0.0
-40 -25 -10
5
-40 -25 -10
20 35 50 65 80 95 110 125
0.005
0.000
VOUT2 = 3.3V
SHDN1 = AGND
SHDN2 = VIN2
-0.005
IOUT2 = 100 µA
-0.010
VOUT2 = 2.5V
-0.015
-0.020
-0.025
VOUT2 = 1.5V
-0.030
20 35 50 65 80 95 110 125
FIGURE 2-29:
PG Active Delay Time-out
vs. Ambient Temperature.
PG Threshold (% of V OUT2)
FIGURE 2-26:
VOUT2 Dropout Voltage vs.
Ambient Temperature (VOUT2 = 3.3V).
5
Ambient temperature (°C)
Ambient Temperature (°C)
VOUT2 Line Regulation (%/V)
SHDN1 = AGND
SHDN2 = VIN2
VOUT2 = 3.3V
0.0
-40
VOUT2 Dropout Voltage (V)
0.30
VOUT2 Load Regulation (%)
Note: Unless otherwise indicated, VIN1 = VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1 µF, L = 4.7 µH,
VOUT1 (ADJ) = 1.8V, TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C. TA = +25°C. Adjustable or fixed
output voltage options can be used to generate the Typical Performance Characteristics.
96
SHDN1 = VIN2
SHDN2 = VIN2
VIN = 3.6V
95
PG Threshold Hi
94
93
92
PG Threshold Low
91
90
-0.035
-40 -25 -10
5
20 35 50 65 80 95 110 125
Ambient Temperature (°C)
FIGURE 2-27:
VOUT2 Line Regulation vs.
Ambient Temperature.
DS21949A-page 12
-40 -25 -10
5
20 35 50 65 80 95 110 125
Ambient Temperature (°C)
FIGURE 2-30:
PG Threshold Voltage vs.
Ambient Temperature.
© 2005 Microchip Technology Inc.
TC1303B
Note: Unless otherwise indicated, VIN1 = VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1 µF, L = 4.7 µH,
VOUT1 (ADJ) = 1.8V, TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C. TA = +25°C. Adjustable or fixed
output voltage options can be used to generate the Typical Performance Characteristics.
10
0.02
PG VOL (V)
0.018
0.016
VOUT2 Noise (μV/—Hz)
SHDN1 = VIN2
SHDN2 = VIN2
VIN = 3.6V
IOL = 1.2 mA
0.014
0.012
125
95
110
80
65
50
35
20
5
-10
-25
-40
0.01
SHDN1 = AGND
SHDN2 = VIN2
1
0.1
VIN = 3.6V
VOUT2 = 2.5V
IOUT2 = 50 mA
0.01
0.01
0.1
Ambient Temperature (°C)
1
10
100
1000
10000
Frequency (kHz)
FIGURE 2-31:
PG Output Voltage Level
Low vs. Ambient Temperature.
FIGURE 2-34:
VOUT2 Noise vs. Frequency.
FIGURE 2-35:
vs. Time.
VOUT1 Load Step Response
FIGURE 2-36:
vs. Time.
VOUT2 Load Step Response
VOUT2 = 2.8V
3.0
2.5
PG VOH (V)
VOUT2 = 2.5V
2.0
1.5
VOUT2 = 1.5V
1.0
0.5
VIN = 3.6V
IOH = 500 µA
SHDN1 = VIN2
SHDN2 = VIN2
0.0
-40 -25 -10
5
20 35 50 65 80 95 110 125
Ambient Temperature (°C)
FIGURE 2-32:
PG Output Voltage Level
High vs. Ambient Temperature.
0
VOUT2 PSRR (dB)
-10
-20
-30
SHDN1 = GND
VOUT2 = 1.5V
IOUT2 = 30 mA
CIN = 0 µF
COUT2 = 1.0 µF
-40
-50
COUT2 = 4.7 µF
-60
-70
-80
0.01
0.1
1
10
100
1000
Frequency (kHz)
FIGURE 2-33:
VOUT2 Power Supply Ripple
Rejection vs. Frequency.
© 2005 Microchip Technology Inc.
DS21949A-page 13
TC1303B
Note: Unless otherwise indicated, VIN1 = VIN2 = SHDN1,2 = 3.6V, COUT1 = CIN = 4.7 µF, COUT2 = 1 µF, L = 4.7 µH,
VOUT1 (ADJ) = 1.8V, TA = +25°C. Boldface specifications apply over the TA range of -40°C to +85°C. TA = +25°C. Adjustable or fixed
output voltage options can be used to generate the Typical Performance Characteristics.
FIGURE 2-37:
VOUT1 and VOUT2 Line Step
Response vs. Time.
FIGURE 2-38:
Waveforms.
DS21949A-page 14
VOUT1 and VOUT2 Startup
FIGURE 2-39:
Waveforms.
VOUT1 and VOUT2 Shutdown
FIGURE 2-40:
Power-Good Output Timing.
© 2005 Microchip Technology Inc.
TC1303B
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:
PIN FUNCTION TABLE
Pin No.
Name
1
SHDN2
2
VIN2
3
VOUT2
LDO Output Voltage Pin
4
PG
Power-good Output Pin
5
AGND
6
3.1
Function
Active Low Shutdown Input for LDO Output Pin
Analog Input Supply Voltage Pin
Analog Ground Pin
VFB / VOUT1 Buck Feedback Voltage (Adjustable Version) / Buck Output Voltage (Fixed Version) Pin
7
SHDN1
8
VIN1
9
LX
10
PGND
EP
Exposed
Pad
Active Low Shutdown Input for Buck Regulator Output Pin
Buck Regulator Input Voltage Pin
Buck Inductor Output Pin
Power Ground Pin
For the DFN package, the center exposed pad is a thermal path to remove heat from the
device. Electrically this pad is at ground potential and should be connected to AGND.
LDO Shutdown Input Pin (SHDN2)
SHDN2 is a logic level input used to turn the LDO Regulator on and off. A logic high (> 45% of VIN), will enable
the regulator output. A logic low (< 15% of VIN) will
ensure that the output is turned off.
3.2
LDO Input Voltage Pin (VIN2)
VIN2 is a LDO power input supply pin. Connect variable
input voltage source to VIN2. Connect VIN1 and VIN2
together with board traces as short as possible. VIN2
provides the input voltage for the LDO regulator. An
additional capacitor can be added to lower the LDO
regulator input ripple voltage.
3.3
LDO Output Voltage Pin (VOUT2)
VOUT2 is a regulated LDO output voltage pin. Connect
a 1 µF or larger capacitor to VOUT2 and AGND for proper
operation.
3.4
Power-Good Output Pin (PG)
PG is an output level indicating that VOUT2 (LDO) is
within 94% of regulation. The PG output is configured
as a push-pull for the TC1303B.
3.5
Analog Ground Pin (AGND)
AGND is the analog ground connection. Tie AGND to the
analog portion of the ground plane (AGND). See the
physical layout information in Section 5.0 “Application
Circuits/Issues” for grounding recommendations.
3.6
Buck Regulator Output Sense Pin
(VFB/VOUT1)
3.7
Buck Regulator Shutdown Input
Pin (SHDN1)
SHDN1 is a logic level input used to turn the buck
regulator on and off. A logic-high (> 45% of VIN), will
enable the regulator output. A logic-low (< 15% of VIN)
will ensure that the output is turned off.
3.8
Buck Regulator Input Voltage Pin
(VIN1)
VIN1 is the buck regulator power input supply pin.
Connect a variable input voltage source to VIN1.
Connect VIN1 and VIN2 together with board traces as
short as possible.
3.9
Buck Inductor Output Pin (LX)
Connect LX directly to the buck inductor. This pin
carries large signal-level current; all connections
should be made as short as possible.
3.10
Power Ground Pin (PGND)
Connect all large-signal level ground returns to PGND.
These large-signal, level ground traces should have a
small loop area and length to prevent coupling of
switching noise to sensitive traces. Please see the
physical layout information supplied in Section 5.0
“Application Circuits/Issues”
for
grounding
recommendations.
3.11
Exposed Pad (EP)
For the DFN package, connect the EP to AGND with
vias into the AGND plane.
For VOUT1 adjustable output voltage options, connect
the center of the output voltage divider to the VFB pin.
For fixed-output voltage options, connect the output of
the buck regulator to this pin (VOUT1).
© 2005 Microchip Technology Inc.
DS21949A-page 15
TC1303B
4.0
DETAILED DESCRIPTION
4.1
Device Overview
The TC1303B combines a 500 mA synchronous buck
regulator with a 300 mA LDO and a power-good output.
This unique combination provides a tiny, low-cost
solution for applications that require two or more
voltage rails. The buck regulator can deliver highoutput current over a wide range of input-to-output
voltage ratios while maintaining high efficiency. This is
typically used for the lower-voltage, high-current
processor core. The LDO is a minimal parts-count
solution, (single-output capacitor), providing a
regulated voltage for an auxiliary rail. The typical LDO
dropout voltage (137 mV @ 200 mA) allows the use of
very low input-to-output LDO differential voltages,
minimizing the power loss internal to the LDO pass
transistor. A power-good output is provided, indicating
that the LDO output is in regulation (TC1303B).
Additional features include independent shutdown
inputs, UVLO, overcurrent and overtemperature
shutdown.
4.2
Synchronous Buck Regulator
The synchronous buck regulator is capable of supplying a 500 mA continuous output current over a wide
range of input and output voltages. The output voltage
range is from 0.8V (min) to 4.5V (max). The regulator
operates in three different modes and automatically
selects the most efficient mode of operation. During
heavy load conditions, the TC1303B buck converter
operates at a high, fixed frequency (2.0 MHz) using
current mode control. This minimizes output ripple and
noise (less than 8 mV peak-to-peak ripple) while maintaining high efficiency (typically > 90%). For standby or
light load applications, the buck regulator will automatically switch to a power-saving Pulse Frequency
Modulation (PFM) mode. This minimizes the quiescent
current draw on the battery, while keeping the buck
output voltage in regulation. The typical buck PFM
mode current is 38 µA. The buck regulator is capable of
operating at 100% duty cycle, minimizing the voltage
drop from input to output for wide input batterypowered applications. For fixed-output voltage applications, the feedback divider and control loop compensation components are integrated, eliminating the need
for external components. The buck regulator output is
protected against overcurrent, short circuit and overtemperature. While shut down, the synchronous buck
N-channel and P-channel switches are off, so the LX
pin is in a high-impedance state (this allows for
connecting a source on the output of the buck regulator
as long as its voltage does not exceed the input
voltage).
DS21949A-page 16
4.2.1
FIXED FREQUENCY PWM MODE
While operating in Pulse Width Modulation (PWM)
mode, the TC1303B buck regulator switches at a fixed
2.0 MHz frequency. The PWM mode is suited for higher
load current operation, maintaining low output noise
and high conversion efficiency. PFM to PWM mode
transition is initiated for any of the following conditions.
• Continuous inductor current is sensed
• Inductor peak current exceeds 100 mA
• The buck regulator output voltage has dropped
out of regulation (step load has occurred)
The typical PFM-to-PWM threshold is 80 mA.
4.2.2
PFM MODE
PFM mode is entered when the output load on the buck
regulator is very light. Once detected, the converter
enters the PFM mode automatically and begins to skip
pulses to minimize unnecessary quiescent current
draw by reducing the number of switching cycles per
second. The typical quiescent current for the switching
regulator is less than 35 µA. The transition from PWM
to PFM mode occurs when discontinuous inductor
current is sensed, or the peak inductor current is less
than 60 mA (typ.). The typical PWM to PFM mode
threshold is 30 mA. For low input-to-output differential
voltages, the PWM to PFM mode threshold can be low
due to the lack of ripple current. It is recommended that
VIN1 be one volt greater than VOUT1 for PWM to PFM
transitions.
4.3
Low Drop Out Regulator (LDO)
The LDO output is a 300 mA low-dropout linear regulator that provides a regulated output voltage with a
single 1 µF external capacitor. The output voltage is
available in fixed options only, ranging from 1.5V to
3.3V. The LDO is stable using ceramic output capacitors that inherently provide lower output noise and
reduce the size and cost of the regulator solution. The
quiescent current consumed by the LDO output is
typically less than 20 µA, with a typical dropout voltage
of 137 mV at 200 mA. The LDO output is protected
against overcurrent and overtemperature.
© 2005 Microchip Technology Inc.
TC1303B
4.4
Power-Good
4.5
A power-good (PG) output signal is generated based
off of the LDO output voltage (VOUT2). A fixed delay
time of approximately 300 ms is generated once the
LDO output voltage is above the power-good threshold
(typically 94% of VOUT2). As VOUT2 falls out of regulation, the falling PG threshold is typically 92% of VOUT2.
The PG output signal is pulled up to VOUT2 indicating
that power is good and pulled low indicating that VOUT2
is out of regulation. The typical quiescent current draw
for power-good circuitry is less than 10 µA.
If the LDO output voltage falls below the power-good
threshold, the power-good output will transition to the
low state. The power-good circuitry has a 165 µs delay
when detecting a falling output voltage. This helps to
increase the noise immunity of the power-good output
and avoiding false triggering of the PG signal during
line and load transients.
Soft Start
Both outputs of the TC1303B are controlled during
startup. Less than 1% of VOUT1 or VOUT2 overshoot is
observed during startup from VIN rising above the
UVLO voltage or SHDN1 or SHDN2 being enabled.
4.6
Overtemperature Protection
The TC1303B has an integrated overtemperature
protection circuit that monitors the device junction
temperature and shuts the device off if the junction temperature exceeds the typical 165°C threshold. If the
overtemperature threshold is reached, the soft start is
reset so that once the junction temperature cools to
approximately 155°C, the device will automatically
restart.
VTH_H
VOUT2
tRPU
VOH
PG
FIGURE 4-1:
tRPD
VOL
Power-Good Timing.
© 2005 Microchip Technology Inc.
DS21949A-page 17
TC1303B
5.0
APPLICATION
CIRCUITS/ISSUES
5.1
Typical Applications
The TC1303B 500 mA buck regulator + 300 mA LDO
with power-good operates over a wide input voltage
range (2.7V to 5.5V) and is ideal for single-cell Li-Ion
battery-powered applications, USB-powered applications, three-cell NiMH or NiCd applications and 3V to
5V regulated input applications. The 10-pin MSOP and
3X3 DFN packages provide a small footprint with
minimal external components.
5.2
Fixed Output Application
A typical VOUT1 fixed output voltage application is
shown in “Typical Application Circuits” on page 3. A
4.7 µF VIN1 ceramic input capacitor, 4.7 µF VOUT1
ceramic capacitor, 1.0 µF ceramic VOUT2 capacitor and
4.7 µH inductor make up the entire external component
solution for this dual-output application. No external
dividers or compensation components are necessary.
For this application, the input voltage range is 2.7V to
4.2V, VOUT1 = 1.5V at 500 mA, while VOUT2 = 2.5V at
300 mA.
5.3
Adjustable Output Application
A typical VOUT1 adjustable output application is also
shown in “Typical Application Circuits” on page 3.
For this application, the buck regulator output voltage is
adjustable by using two external resistors as a voltage
divider. For adjustable output voltages, it is recommended that the top resistor divider value be 200 kΩ.
The bottom resistor divider can be calculated using the
following formula:
EQUATION 5-1:
V FB
R BOT = R TOP × ⎛ --------------------------------⎞
⎝ VOUT1 – V FB⎠
An additional VIN2 capacitor can be added to reduce
high frequency noise on the LDO input voltage pin
(VIN2). This additional capacitor (1 µF on page 3) is not
necessary for typical applications.
5.4
Input and Output Capacitor
Selection
As with all buck-derived dc-dc switching regulators, the
input current is pulled from the source in pulses. This
places a burden on the TC1303B input filter capacitor.
In most applications, a minimum of 4.7 µF is recommended on VIN1 (buck regulator input voltage pin). In
applications that have high source impedance or have
long leads (10 inches) connecting to the input source,
additional capacitance should be used. The capacitor
type can be electrolytic (aluminum, tantalum, POSCAP,
OSCON) or ceramic. For most portable electronic
applications, ceramic capacitors are preferred due to
their small size and low cost.
For applications that require very low noise on the LDO
output, an additional capacitor (typically 1 µF) can be
added to the VIN2 pin (LDO input voltage pin).
Low ESR electrolytic or ceramic can be used for the
buck regulator output capacitor. Again, ceramic is
recommended because of its physical attributes and
cost. For most applications, a 4.7 µF is recommended.
Refer to Table 5-1 for recommended values. Larger
capacitors (up to 22 µF) can be used. There are some
advantages in load step performance when using
larger value capacitors. Ceramic materials X7R and
X5R have low temperature coefficients and are well
within the acceptable ESR range required.
TABLE 5-1:
TC1303B RECOMMENDED
CAPACITOR VALUES
C(VIN1)
C(VIN2)
COUT1
COUT2
min
4.7 µF
none
4.7 µF
1 µF
max
none
none
22 µF
10 µF
Example:
RTOP = 200 kΩ
VOUT1 = 2.1V
VFB
= 0.8V
RBOT = 200 kΩ x (0.8V/(2.1V – 0.8V))
RBOT = 123 kΩ (Standard Value = 121 kΩ)
For adjustable output applications, an additional R-C
compensation is necessary for the buck regulator
control loop stability. Recommended values are:
RCOMP = 4.99 kΩ
CCOMP = 33 pF
DS21949A-page 18
© 2005 Microchip Technology Inc.
TC1303B
5.5
Inductor Selection
For most applications, a 4.7 µH inductor is recommended to minimize noise. There are many different
magnetic core materials and package options to select
from. That decision is based on size, cost and acceptable radiated energy levels. Toroid and shielded ferrite
pot cores will have low radiated energy but tend to be
larger and higher is cost. With a typical 2.0 MHz switching frequency, the inductor ripple current can be
calculated based on the following formulas.
TABLE 5-2:
Part
Number
TC1303B RECOMMENDED
INDUCTOR VALUES
Value
(µH)
DCR
MAX
Ω
IDC (A)
(MAX)
Size
WxLxH (mm)
Coiltronics®
SD10
2.2
0.091
1.35
5.2, 5.2, 1.0 max.
SD10
3.3
0.108
1.24
5.2, 5.2, 1.0 max.
SD10
4.7
0.154
1.04
5.2, 5.2, 1.0 max.
2.2
0.075
1.80
5.2, 5.2, 1.2 max.
SD12
3.3
0.104
1.42
5.2, 5.2, 1.2 max.
SD12
4.7
0.118
1.29
5.2, 5.2, 1.2 max.
Coiltronics
EQUATION 5-2:
SD12
V OUT
DutyCycle = ------------V IN
®
Sumida Corporation
Duty cycle represents the percentage of switch-on
time.
CMD411
2.2
0.116
0.950 4.4, 5.8, 1.2 max.
CMD411
3.3
0.174
0.770 4.4, 5.8, 1.2 max.
EQUATION 5-3:
CMD411
4.7
0.216
0.750 4.4, 5.8, 1.2 max.
1008PS
4.7
0.35
1.0
3.8,3.8,2.74 max.
1812PS
4.7
0.11
1.15
5.9,5.0, 3.81 max
1
T ON = DutyCycle × ---------F SW
Where:
FSW = Switching Frequency.
The inductor ac ripple current can be calculated using
the following relationship:
EQUATION 5-4:
ΔI L
V L = L × -------Δt
Where:
VL = voltage across the inductor (VIN – VOUT)
Δt = on-time of P-channel MOSFET
Solving for ΔIL = yields:
EQUATION 5-5:
VL
ΔI L = ------ × Δt
L
When considering inductor ratings, the maximum DC
current rating of the inductor should be at least equal to
the maximum buck regulator load current (IOUT1), plus
one half of the peak-to-peak inductor ripple current
(1/2 * ΔIL). The inductor DC resistance can add to the
buck converter I2R losses. A rating of less than 200 mΩ
is recommended. Overall efficiency will be improved by
using lower DC resistance inductors.
© 2005 Microchip Technology Inc.
Coilcraft
5.6
5.6.1
®
Thermal Calculations
BUCK REGULATOR OUTPUT
(VOUT1)
The TC1303B is available in two different 10-pin
packages (MSOP and 3X3 DFN). By calculating the
power dissipation and applying the package thermal
resistance, (θJA), the junction temperature is estimated.
The maximum continuous junction temperature rating
for the TC1303B is 125°C.
To quickly estimate the internal power dissipation for
the switching buck regulator, an empirical calculation
using measured efficiency can be used. Given the
measured efficiency (Section 2.0 “Typical Performance Curves”), the internal power dissipation is
estimated below.
EQUATION 5-6:
OUT1 × I OUT1⎞
⎛V
------------------------------------⎝ Efficiency ⎠ – ( V OUT1 × IOUT1 ) = PDissipation
The first term is equal to the input power (definition of
efficiency, POUT/PIN = Efficiency). The second term is
equal to the delivered power. The difference is internal
power dissipation. This is an estimate assuming that
most of the power lost is internal to the TC1303B.
There is some percentage of power lost in the buck
inductor, with very little loss in the input and output
capacitors.
DS21949A-page 19
TC1303B
As an example, for a 3.6V input, 1.8V output with a load
of 400 mA, the efficiency taken from Figure 2-7 is
approximately 84%. The internal power dissipation is
approximately 171 mW.
5.6.2
LDO OUTPUT (VOUT2)
The internal power dissipation within the TC1303B
LDO is a function of input voltage, output voltage and
output current. The following equation can be used to
calculate the internal power dissipation for the LDO.
EQUATION 5-7:
placed near their respective pins to minimize trace
length. The CIN1 and COUT1 capacitor returns are connected closely together at the PGND plane. The LDO
optional input capacitor (CIN2) and LDO output capacitor COUT2 are returned to the AGND plane. The analog
ground plane and power ground plane are connected
at one point (shown near L1). All other signals (SHDN1,
SHDN2, feedback in the adjustable output case)
should be referenced to AGND and have the AGND
plane underneath them.
- Via
AGND to PGND
PLDO = ( V IN ( MAX ) ) – V OUT2 ( MIN ) ) × I OUT2 ( MAX ) )
= LDO Pass device internal
power dissipation
PLDO
VOUT(MIN) = LDO minimum output voltage
The maximum power dissipation capability for a
package can be calculated given the junction-toambient thermal resistance and the maximum ambient
temperature for the application. The following equation
can be used to determine the package’s maximum
internal power dissipation.
LDO POWER DISSIPATION
EXAMPLE
Input Voltage
VIN = 5V±10%
LDO Output Voltage and Current
VOUT = 3.3V
PGND
CIN2
1
10
+VIN2
2
9
+VOUT2
3
8
COUT2
PLDO(MAX) = (VIN(MAX) – VOUT(MIN)) x IOUT(MAX)
PLDO = (5.5V) – (0.975 x 3.3V))
x 300 mA
Some basic design guidelines should be used when
physically placing the TC1303B on a Printed Circuit
Board (PCB). The TC1303B has two ground pins, identified as AGND (analog ground) and PGND (power
ground). By separating grounds, it is possible to
minimize the switching frequency noise on the LDO
output. The first priority, while placing external components on the board, is the input capacitor (CIN1). Wiring
should be short and wide; the input current for the
TC1303B can be as high as 800 mA. The next priority
would be the buck regulator output capacitor (COUT1)
and inductor (L1). All three of these components are
DS21949A-page 20
TC1303B 6
PGND Plane
FIGURE 5-1:
Component Placement,
Fixed 10-Pin MSOP.
There will be some difference in layout for the 10-pin
DFN package due to the thermal pad. A typical fixedoutput DFN layout is shown below. For the DFN layout,
the VIN1 to VIN2 connection is routed on the bottom of
the board around the TC1303B thermal pad.
- Via
+VOUT1
AGND to PGND
* CIN2 Optional
COUT1
AGND
L1
PGND
CIN2
1
COUT2
2
3
4
5
+VIN2
PCB Layout Information
7
5
+VIN1
AGND Plane
PLDO = 684.8 mW
5.7
4
CIN1
AGND
IOUT = 300 mA
Internal Power Dissipation
COUT1
L1
AGND
VIN(MAX) = Maximum input voltage
5.6.3
+VOUT1
* CIN2 Optional
Where:
+VOUT2
AGND
10
9
8
7
6
PGND
CIN1
+VIN1
TC1303B
PGND Plane
AGND Plane
FIGURE 5-2:
Component Placement,
Fixed 10-Pin DFN.
© 2005 Microchip Technology Inc.
TC1303B
5.8
Design Example
VOUT1 = 2.0V @ 500 mA
VOUT2 = 3.3V @ 300 mA
VIN = 5V±10%
L = 4.7µH
Calculate PWM mode inductor ripple current
Nominal Duty
Cycle = 2.0V/5.0V = 40%
P-channel
Switch-on time = 0.40 x 1/(2 MHz) = 200 ns
VL = (VIN-VOUT1) = 3V
ΔIL = (VL/L) x TON = 128 mA
Peak inductor current:
IL(PK) = IOUT1+1/2ΔIL = 564 mA
Switcher power loss:
Use efficiency estimate for 1.8V from Figure 2-7
Efficiency = 84%, PDISS1 = 171 mW
Resistor Divider:
RTOP = 200 kΩ
RBOT = 133 kΩ
LDO Output:
PDISS2 = (VIN(MAX) –
VOUT2(MIN)) x IOUT2(MAX)
PDISS2 = (5.5V – (0.975) x 3.3V) x 300 mA
PDISS2 = 684.8 mW
Total
Dissipation = 171 mW + 685 mW = 856 mW
Junction Temp Rise and Maximum Ambient
Operating Temperature Calculations
10-Pin MSOP (4-Layer Board with internal Planes)
RθJA = 113° C/Watt
Junction Temp.
Rise = 856 mW x 113° C/Watt = 96.7°C
Max. Ambient
Temperature = 125°C - 96.7°C
Max. Ambient
Temperature = 28.3°C
10-Pin DFN
RθJA = 41° C/Watt (4-Layer Board with
internal planes and 2 vias)
Junction Temp.
Rise = 856 mW x 41° C/Watt = 35.1°C
Max. Ambient
Temperature = 125°C - 35.1°C
Max. Ambient
Temperature = 89.9°C
This is above the 85°C max. ambient temperature.
© 2005 Microchip Technology Inc.
DS21949A-page 21
TC1303B
6.0
PACKAGING INFORMATION
6.1
Package Marking Information
10-Lead MSOP*
Example:
XXXXXX
YWWNNN
11H0/E
520256
— 1 = TC1303B
— 1 = 1.375V VOUT1
— H = 2.6V VOUT2
— 0 = Default
* The MSOP package for this device has not
been qualified at the time of this publication.
Contact your Microchip sales office for
availability.
VOUT1
Code
A
3.3V
B
Example:
XXXX
YYWW
NNN
11H0
0520
256
Third letter represents VOUT2 configuration:
Second letter represents VOUT1 configuration:
Code
10-Lead DFN
VOUT2
Code
VOUT1
Code
VOUT2
A
3.3V
J
2.4V
S
1.5V
B
3.2V
K
2.3V
T
—
C
3.1V
L
2.2V
U
—
D
3.0V
M
2.1V
V
—
E
2.9V
N
2.0V
W
—
VOUT1
Code
J
2.4V
S
1.5V
3.2V
K
2.3V
T
1.4V
C
3.1V
L
2.2V
U
1.3V
D
3.0V
M
2.1V
V
1.2V
E
2.9V
N
2.0V
W
1.1V
F
2.8V
O
1.9V
X
1.0V
G
2.7V
P
1.8V
Y
0.9V
Code
H
2.6V
Q
1.7V
Z
Adj
0
Default
2
+50 mV to V2
I
2.5V
R
1.6V
1
1.375V
1
+50 mV to V1
3
+50 mV to V1
and V2
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
DS21949A-page 22
VOUT1
Code
F
2.8V
O
1.9V
X
—
G
2.7V
P
1.8V
Y
—
H
2.6V
Q
1.7V
Z
—
I
2.5V
R
1.6V
Fourth letter represents +50 mV Increments:
Code
Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
© 2005 Microchip Technology Inc.
TC1303B
10-Lead Plastic Dual Flat No Lead Package (MF) 3x3x0.9 mm Body (DFN) – Saw Singulated
p
b
E
n
L
D
PIN 1
ID INDEX
AREA
(NOTE 2)
D2
EXPOSED
METAL
PAD
2
1
E2
TOP VIEW
BOTTOM VIEW
A
A3
EXPOSED
TIE BAR
(NOTE 1)
A1
Number of Pins
Pitch
Overall Height
Standoff
Lead Thickness
Overall Length
Exposed Pad Length
Overall Width
Exposed Pad Width
Lead Width
Lead Length
Units
Dimension Limits
n
e
(Note 3)
(Note 3)
A
A1
A3
E
E2
D
D2
b
L
MIN
.031
.000
.112
.055
.112
.047
.008
.012
INCHES
NOM
10
.020 BSC
.035
.001
.008 REF.
.118
-.118
-.010
.016
MAX
.039
.002
.124
.096
.124
.069
.015
.020
MILLIMETERS*
NOM
10
0.50 BSC
0.80
0.90
0.00
0.02
0.20 REF.
2.85
3.00
1.39
-2.85
3.00
1.20
-0.18
0.25
0.30
0.40
MIN
MAX
1.00
0.05
3.15
2.45
3.15
1.75
0.30
0.50
*Controlling Parameter
Notes:
1. Package may have one or more exposed tie bars at ends.
2. Pin 1 visual index feature may vary, but must be located within the hatched area.
3. Exposed pad dimensions vary with paddle size.
4. JEDEC equivalent: Not registered
Drawing No. C04-063
© 2005 Microchip Technology Inc.
Revised 05/24/04
DS21949A-page 23
TC1303B
10-Lead Plastic Micro Small Outline Package (UN) (MSOP*)
E
E1
p
D
2
B
n
1
α
A
φ
c
A2
A1
L
(F)
β
L1
Units
Dimension Limits
n
p
MIN
INCHES
NOM
10
.020 TYP
.033
.193 BSC
.118 BSC
.118 BSC
.024
.037 REF
.009
-
MAX
MILLIMETERS*
NOM
10
0.50 TYP.
0.85
0.75
0.00
4.90 BSC
3.00 BSC
3.00 BSC
0.60
0.40
0.95 REF
0°
0.08
0.15
0.23
5°
5°
MIN
MAX
Number of Pins
Pitch
.043
Overall Height
A
.037
Molded Package Thickness
A2
.030
Standoff
.006
A1
.000
Overall Width
E
Molded Package Width
E1
Overall Length
D
Foot Length
.031
L
.016
Footprint
F
φ
Foot Angle
0°
8°
c
Lead Thickness
.009
.003
Lead Width
.012
B
.006
α
Mold Draft Angle Top
5°
15°
β
Mold Draft Angle Bottom
5°
15°
*Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed .010" (0.254mm) per side.
1.10
0.95
0.15
0.80
8°
0.23
0.30
15°
15°
JEDEC Equivalent: MO-187
Drawing No. C04-021
* The MSOP package for the TC1303B has not been qualified at the time of this publication.
Contact your Microchip sales office for availability.
DS21949A-page 24
© 2005 Microchip Technology Inc.
TC1303B
APPENDIX A:
REVISION HISTORY
Revision A (June 2005)
• Original Release of this Document.
© 2005 Microchip Technology Inc.
DS21949A-page 25
TC1303B
NOTES:
DS21949A-page 26
© 2005 Microchip Technology Inc.
TC1303B
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO.
TC1303
X-
X
X
X
X
Type VOUT1 VOUT2 +50 mV Temp
Increments Range
B
XX
XX
Package
Tube
or
Tape &
Reel
Device:
TC1303B: PWM/LDO combo with Power-Good.
Options
Code
VOUT1
Code
VOUT2
Code
+50 mV
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
1
3.3V
3.2V
3.1V
3.0V
2.9V
2.8V
2.7V
2.6V
2.5V
2.4V
2.3V
2.2V
2.1V
2.0V
1.9V
1.8V
1.7V
1.6V
1.5V
1.4V
1.3V
1.2V
1.1V
1.0V
0.9V
Adjustable
1.375V
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
1
3.3V
3.2V
3.1V
3.0V
2.9V
2.8V
2.7V
2.6V
2.5V
2.4V
2.3V
2.2V
2.1V
2.0V
1.9V
1.8V
1.7V
1.6V
1.5V
0
1
2
3
Default
+50 mV to V1
+50 mV to V2
+50 mV to V1
and V2
Examples:
a)
TC1303B-IA0EMF:
b)
TC1303B-ZA0EUN:
c)
TC1303B-PG0EMFTR:
2.5V, 3.3V, Default,
10LD DFN pkg.
Adj, 3.3V, Default,
10LD MSOP pkg.
1.8V, 2.7V, Default,
10LD DFN pkg.
Tape and Reel
* Contact Factory for Alternate Output Voltage and Reset
Voltage Configurations.
Temperature
Range:
E
= -40°C to +85°C
Package:
MF
UN
= Dual Flat, No Lead (3x3 mm body), 10-lead
= Plastic Micro Small Outline (MSOP), 10-lead
(The MSOP package for this device has not been
qualified at the time of this publication. Contact your
Microchip sales office for availability.)
Tube or
Tape and Reel:
Blank
TR
= Tube
= Tape and Reel
© 2005 Microchip Technology Inc.
DS21949A-page 27
TC1303B
NOTES:
DS21949A-page 28
© 2005 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED,
WRITTEN OR ORAL, STATUTORY OR OTHERWISE,
RELATED TO THE INFORMATION, INCLUDING BUT NOT
LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE,
MERCHANTABILITY OR FITNESS FOR PURPOSE.
Microchip disclaims all liability arising from this information and
its use. Use of Microchip’s products as critical components in
life support systems is not authorized except with express
written approval by Microchip. No licenses are conveyed,
implicitly or otherwise, under any Microchip intellectual property
rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro,
PICSTART, PRO MATE, PowerSmart, rfPIC, and
SmartShunt are registered trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.
AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB,
PICMASTER, SEEVAL, SmartSensor and The Embedded
Control Solutions Company are registered trademarks of
Microchip Technology Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, dsPICDEM,
dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR,
FanSense, FlexROM, fuzzyLAB, In-Circuit Serial
Programming, ICSP, ICEPIC, Linear Active Thermistor,
MPASM, MPLIB, MPLINK, MPSIM, PICkit, PICDEM,
PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo,
PowerMate, PowerTool, rfLAB, rfPICDEM, Select Mode,
Smart Serial, SmartTel, Total Endurance and WiperLock are
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2005, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 quality system certification for
its worldwide headquarters, design and wafer fabrication facilities in
Chandler and Tempe, Arizona and Mountain View, California in
October 2003. The Company’s quality system processes and
procedures are for its PICmicro® 8-bit MCUs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
© 2005 Microchip Technology Inc.
DS21949A-page 29
WORLDWIDE SALES AND SERVICE
AMERICAS
ASIA/PACIFIC
ASIA/PACIFIC
EUROPE
Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://support.microchip.com
Web Address:
www.microchip.com
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Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
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Tel: 91-80-2229-0061
Fax: 91-80-2229-0062
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Tel: 86-10-8528-2100
Fax: 86-10-8528-2104
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Tel: 91-11-5160-8631
Fax: 91-11-5160-8632
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Tel: 43-7242-2244-399
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Tel: 45-4450-2828
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Tel: 650-215-1444
Fax: 650-961-0286
Toronto
Mississauga, Ontario,
Canada
Tel: 905-673-0699
Fax: 905-673-6509
04/20/05
DS21949A-page 30
© 2005 Microchip Technology Inc.