TS3410
1A / 1.4MHz Synchronous Buck Converter
SOT-25
Pin Definition:
1. EN
2. Ground
3. Switching Output
4. Input
5. Feedback
General Description
TS3410 is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode
architecture. The device is available in an adjustable version. Supply current with no load is 250uA and drops to
<1uA in shutdown. The 2.5V to 6V input voltage range makes TS3410 ideally suited for single Li-Ion, two to four
AA battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in
portable systems. PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive
applications. Switching frequency is internally set at 1.4MHz, allowing the use of small surface mount inductors
and capacitors. The internal synchronous switch increases efficiency and decreases need of an external Schottky
diode. Low output voltages are easily supported with the 0.6V feedback reference voltage.
Features
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High Efficiency: Up to 96%
2.5V to 6V Input Voltage Range
Output Voltage from 0.6V to VIN
Short Circuit Protection (SCP)
Build in Soft-Start Function
1.4MHz Constant Frequency Operation
Up to 1A Output Current
Low Quiescent Current: 250uA (Typ.)
No Schottky Diode Required in Application
≤1uA
Shutdown Current
Current Mode Operation for Excellent Line and
Load Transient Response
Application
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Cellular Phones
Digital Still Cameras
Portable Electronics
USB Devices
Pin Description
Name
EN
GND
SW
Description
Power-off pin
H：normal operation
L：Step-down operation stopped
(All circuits deactivated)
Ground pin
Switch output pin. Connect external inductor
here. Minimize trace area at this pin to
reduce EMI.
IC power supply pin
Output Feedback pin
Ordering Information
Part No.
Package
Packing
TS3410CX5 RFG
SOT-25
3Kpcs/ 7” Reel
“G”
denotes for Halogen free products
VCC
FB
Application Circuit
V
IN
=2.5V~6V
U1
VIN
EN
V
OUT
=1.8V
L1
SW
FB
2.7uH
R1
600K
C3
15p
C2
10u
C1
4.7u
GND
AX3513
V
OUT
= 0.6 * (1+R1/R2)
R2=100K~330K
R2
300K
Document Number: DS_P0000244
1
Version: D15
TS3410
1A / 1.4MHz Synchronous Buck Converter
Absolute Maximum Rating
Characteristics
V
IN
Pin Voltage
Feedback Pin Voltage
RUN Pin Voltage
Switch Pin Voltage
Peak SW Sink & Source Current
Power Dissipation
Storage Temperature Range
Operating Temperature Range
Junction Temperature
Thermal Resistance from Junction to case
Thermal Resistance from Junction to ambient
Symbol
V
IN
V
FB
V
RUN
V
SW
I
PSW
P
D
T
ST
T
OP
T
J
θ
JC
θ
JA
2
Rating
Gnd - 0.3 to Gnd + 6.5
Gnd - 0.3 to V
IN
+ 0.3
Gnd - 0.3 to V
IN
+ 0.3
Gnd - 0.3 to V
IN
+ 0.3
1.4
(T
J
-T
A
) /
θ
JA
-40 to +150
-40 to +85
+125
110
250
Unit
V
V
V
V
A
mW
°C
°C
°C
°C/W
°C/W
Note1:
θ
JA
is measured with the PCB copper area of approximately 1 in (Multi-layer). that need connect to Gnd pin
of the TS3410.
Electrical Specifications
(Ta = 25
o
C, V
IN
=V
RUN
=3.6V unless otherwise noted)
Characteristics
Feedback Voltage
Quiescent Current
Feedback Bias Current
Shutdown Supply Current
Maximum Output Current
Current Limit
Line Regulation
Load Regulation
Oscillation Frequency
R
DS(ON)
of P-CH MOSFET
R
DS(ON)
of N-CH MOSFET
Efficiency
EN pin logic Input
Threshold Voltage
EN Pin Input Current
Thermal shutdown
Symbol
V
FB
I
CCQ
I
FB
I
SD
I
OUT(MAX)
I
LIMIT
△V
OUT
/V
OUT
△V
OUT
/V
OUT
F
OSC
R
DSON
R
DSON
E
FFI
V
ENL
V
ENH
I
EN
T
DS
Conditions
T
A
=25℃,I
OUT
=50mA
-40°C≤T
A
≤
85°C
V
FB
=0.5V
V
FB
=0.65V
V
RUN
=0V
V
CC
=3V, V
OUT
=1.8V
V
CC
=3V
V
CC
= 2.5V~5.5V
I
OUT
= 0.01 to 0.6A
SW pin
I
SW
= 500mA
Note 1
V
OUT
=3.3V,I
OUT
= 0.5A
Min
0.588
0.582
--
--
--
1
1.2
--
--
1.1
--
--
--
--
1.5
--
--
Typ
0.6
0.6
250
--
0.1
--
1.4
0.04
0.5
1.4
0.3
0.25
94
--
--
±0.1
140
Max
0.612
0.618
350
±30
1
--
--
0.4
--
1.7
0.4
0.35
--
0.4
Units
V
uA
nA
uA
A
A
%
%
MHz
Ω
Ω
%
V
--.
±1
--
uA
°C
Thermal
T
SH
--
30
--
°C
shutdown Hysteresis
Note 1:
Guaranteed by Design
Note 2:
100% production test at +25°C. Specifications over the temperature range are guaranteed by design and
characterization.
Document Number: DS_P0000244
2
Version: D15
TS3410
1A / 1.4MHz Synchronous Buck Converter
Block Diagram
VIN
OSC
REF
0.6V
SET
SLOPE
COMP
Isense
AMP
Soft-Star
-
FB
+
-
+
Icomp
RESET
PWM
LOGIC
NON-OVERLAP
CONTROL
Over-Temperature and
Short-Circuit Protection
Enable Logic
EN
Function Description
Operation
TS3410 is a monolithic switching mode step-down DC-DC converter. It utilizes internal MOSFETs to achieve high
efficiency and can generate very low output voltage by using internal reference at 0.6V. It operates at a fixed
switching frequency, and uses the slope compensated current mode architecture. This step-down DC-DC
Converter supplies minimum 1000mA output current at input voltage range from 2.5V to 5.5V.
Current Mode PWM Control
Slope compensated current mode PWM control provides stable switching and cycle-by-cycle current limit for
excellent load and line transient responses and protection of the internal main switch (P-Ch MOSFET) and
synchronous rectifier (N-CH MOSFET). During normal operation, the internal P-Ch MOSFET is turned on for a
certain time to ramp the inductor current at each rising edge of the internal oscillator, and switched off when the
peak inductor current is above the error voltage. The current comparator, ICOMP, limits the peak inductor current.
When the main switch is off, the synchronous rectifier will be turned on immediately and stay on until either the
inductor current starts to reverse, as indicated by the current reversal comparator, IZERO, or the beginning of the
next clock cycle..
Document Number: DS_P0000244
3
-
Izero
COMP
+
+
-
SW
GND
Version: D15
TS3410
1A / 1.4MHz Synchronous Buck Converter
Application Information
Setting the Output Voltage
Application circuit item shows the basic application circuit with TS3410 adjustable output version. The external
resistor sets the output voltage according to the following formula:
Table 1: Resistor Select for Output Voltage Setting
VOUT
R2
R1
1.2V
1.5V
1.8V
2.5V
3.3V
5V
300K
300K
300K
150K
120K
124K
300K
450K
600K
470K
540K
910K
Inductor Selection
For most designs, the TS3410 operates with inductors of 2.2µH to 3.3µH. Low inductance values are physically
smaller but require faster switching, which results in some efficiency loss. The inductor value can be derived from
the following formula:
Table 2: Inductor Select for Output Voltage Setting (V
IN
=3.6V)
VOUT
1.2V
1.5V
1.8V
2.5V
Inductor
2.7uH
2.7uH
Part Number
7440430027
7440430027
WE-TPC
Note: Part Type MH or M (www.we-online.com)
2.7uH
7440430027
2.2uH
7440430022
Where is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high
ripple currents. Choose inductor ripple current approximately 20% of the maximum load current 1A,
∆IL=200mA.
For output voltages above 2.0V, when light-load efficiency is important, the minimum recommended inductor is
2.7µH. For optimum voltage-positioning load transients, choose an inductor with DC series resistance in the 50mΩ
to 150mΩ range. For higher efficiency at heavy loads (above 200mA), or minimal load regulation (but some
transient overshoot), the resistance should be kept below 100mΩ. The DC current rating of the inductor should be
at least equal to the maximum load current plus half the ripple current to prevent core saturation (1000mA+100mA)
Input Capacitor Selection
The input capacitor reduces the surge current drawn from the input and switching noise from the device. The input
capacitor impedance at the switching frequency shall be less than input source impedance to prevent high
frequency switching current passing to the input. A low ESR input capacitor sized for maximum RMS current must
be used. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and
small temperature coefficients. A 4.7µF ceramic capacitor for most applications is sufficient.
Output Capacitor Selection
The output capacitor is required to keep the output voltage ripple small and to ensure regulation loop stability. The
output capacitor must have low impedance at the switching frequency. Ceramic capacitors with X5R or X7R
dielectrics are recommended due to their low ESR and high ripple current.
Compensation Capacitor Selection
The compensation capacitors for increasing phase margin provide additional stability. It is required and more than
15pF. Please refer to demo board schematic for design.
Document Number: DS_P0000244
4
Version: D15
TS3410
1A / 1.4MHz Synchronous Buck Converter
Electrical Characteristics Curve
Figure 1. Output Voltage vs. Input Voltage
Figure 2. Current Limit vs. Input Voltage
Figure 3. Quiescent Current vs. Input Voltage
Figure 4. Threshold Voltage vs. Input Voltage
Figure 5. Output Voltage vs. Temperature
Figure 6. Quiescent Current vs. Temperature
Document Number: DS_P0000244
5
Version: D15
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