TC115
DS21361D-page 2 2002-2012 Microchip Technology Inc.
1.0 ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings†
Power Supply Voltage (PS)...............................................12V
Power Dissipation ......................................................500 mW
LX Sink Current......................................................400 mA pk
SHDN
Input Voltage..........................................................12V
Operating Temperature Range........................-40°C to +85°C
Storage Temperature Range.........................-40°C to +125°C
† Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to the device. These
are stress ratings only and functional operation of the device
at these or any other conditions above those indicated in the
operation sections of the specifications is not implied.
Exposure to Absolute Maximum Rating conditions for
extended periods may affect device reliability.
PIN FUNCTION TABLE
DC CHARACTERISTICS
Symbol Description
NC Not connected
PS Power and voltage sense input
SHDN
Shutdown input
LX Inductor switch output
GND Ground terminal
Electrical Specifications: Unless otherwise noted, V
OUT
= 5V, T
A
= +25°C. Circuit configuration is illustrated in Figure 5-1.
Parameters Sym Min Typ Max Units Conditions
Operating Supply Voltage V
IN
0.9 — 10.0 V Note 5
Start-Up Supply Voltage V
START
——0.9VI
OUT
= 1 mA
LX Maximum Sink Current I
LXMAX
— — 350 mA
LX Limit Frequency f
LIM
— 200 — kHz V
LX
= VLX
LIM
LX Limit Voltage VLX
LIM
0.7 — 1.3 V Note 2
No Load Supply Current I
DD
—1326µAI
OUT
= 0, V
IN
= V
OUT
x 0.8 (Note 3)
Boost Mode Supply Current I
CC
— 80 135 µA No external components,
V
IN
= (0.95 x V
OUT
) applied to PS (or
V
DD
) input
Standby Supply Current I
STBY
— 9 17 µA No external components,
V
IN
= (1.1 x V
OUT
) applied to PS
(or V
DD
) input
Shutdown Supply Current I
SD
— — 0.5 µA SHDN = 0V
Oscillator Frequency f
OSC
85 100 115 kHz Note 2, Note 4
Output Voltage V
OUT
V
R
x 0.975 V
R
V
R
x 1.025 V V
IN
= 2.2V minimum (Note 1)
LX Output ON Resistance Rswon — 1.4 2.4 V
LX
= 0.4V
Duty Cycle
(PFM Operating Mode)
PFMDUTY 10 17 25 % No external components
Maximum Duty Cycle MAX-
DUTY
80 87 92 % Note 4
Soft Start Time t
SS
4 10 20 msec
Efficiency h — 85 — %
SHDN
Input Logic High V
IH
0.75 — — V
SHDN
Input Logic Low V
IL
— — 0.20 V
Note 1: V
R
is the nominal factory-programmed output voltage setting.
2: VLX
LIM
is the voltage on the LX pin (with internal switch ON) that will cause the oscillator to run at twice nominal
frequency in to limit the switch current through the internal N-channel switching transistor.
3: Measured with D
1
= MA735 (reverse current < 1 µA at a reverse voltage of 10V).
4: With TC115 operating in PWM mode.
5: See Section 4.4, “Behavior When V
IN
is Greater Than the Factory-Programmed V
OUT
Setting”.
