Datasheet

C
SS
100 nF
C
OUT
1
4
56
3 2
7
TPS61085
8
L
3.3 Hµ
V
3.3 V ±20%
IN
C
10 F
16 V
IN
µ
C
1 F
16 V
BY
µ
IN
EN
FREQ
GND
SW
FB
COMP
SS
D
PMEG2010AEH
V
12 V/600 mA max
S
R1
158 kΩ
R2
18.2 kΩ
2* 10 µF
25 V
R
47 k
COMP
Ω
C
1.6 nF
COMP
TPS61085
www.ti.com SLVS859A –JUNE 2008–REVISED APRIL 2012
Frequency Select Pin (FREQ)
The frequency select pin FREQ allows to set the switching frequency of the device to 650 kHz (FREQ = low) or
1.2 MHz (FREQ = high). Higher switching frequency improves load transient response but reduces slightly the
efficiency. The other benefits of higher switching frequency are a lower output ripple voltage. The use of the 1.2
MHz switching frequency is recommended unless light load efficiency is a major concern.
Undervoltage Lockout (UVLO)
To avoid mis-operation of the device at low input voltages an undervoltage lockout is included that disables the
device, if the input voltage falls below 2.2 V.
Thermal Shutdown
A thermal shutdown is implemented to prevent damages due to excessive heat and power dissipation. Typically
the thermal shutdown threshold happens at a junction temperature of 150°C. When the thermal shutdown is
triggered the device stops switching until the temperature falls below typically 136°C. Then the device starts
switching again.
Overvoltage Prevention
If overvoltage is detected on the FB pin (typically 3 % above the nominal value of 1.238 V) the part stops
switching immediately until the voltage on this pin drops to its nominal value. This prevents overvoltage on the
output and secures the circuits connected to the output from excessive overvoltage.
APPLICATION INFORMATION
General Boost Application Circuits
Figure 14. Typical Application, 3.3 V to 12 V (f
S
= 1.2 MHz)
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