TB7100F
Toshiba BiCD Integrated Circuit
Silicon Monolithic
TB7100F
Step-down DC-DC Converter IC
The TB7100F is a single-chip step-down DC-DC converter IC.
Equipped with a built-in high-speed and low on-resistance power
MOSFET, and utilizing a chopper circuit, this IC can achieve a high
efficiency in a wide load current range.
Features
•
Capable of high current drive (I
OUT
= maximum of 700 mA),
using only a few external components
•
High efficiency (η = 90% or higher) (@V
IN
= 5V, V
OUT
= 3.3V,
and I
OUT
= 300 mA).
•
Operating voltage (V
IN
) range: 3 to 5.5 V
•
Low on-resistance (R
DS(ON)
): 0.27
Ω
(typ.) if V
IN
= 5 V
•
High oscillation frequency of 550 kHz (typ.), making it possible to use small external components.
•
Uses external phase compensation, assuring a high degree of design freedom in selecting external components and
determining a loop response.
•
Employs a current mode architecture with excellent fast load response.
•
A small surface mount-type ceramic capacitor can be used as an output smoothing capacitor.
•
Housed in a small surface-mount package (PS-8) with a low thermal resistance.
SON8-P-0303-0.65A(PS-8)
Weight
: 0.016 g (Typ.)
Pin Assignment
Marking
Part number
COMP
1
8
FB
7100
※
・The
dot (•) on the top surface indicates pin 1.
*: Lot number
R
T
2
7
ENB
PGND
3
6
V
IN
SGND
4
5
SW
Due to its MOS structure, this product is sensitive to electrostatic discharge. Handle with care.
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2004-09-10
TB7100F
Block Diagram
V
IN
(pin 6)
ENB
(pin 7)
R
T
(pin 2)
Reference
voltage
supply
1.2 V
Current
detection
+
-
Oscillator
Control
logic
Driver
SW (pin 5)
FB (pin 8)
Temperature
detection
Error amplifier -
+
Reference
voltage (0.8 V)
SGND
(pin 4)
PGND
(pin 3)
COMP
(pin 1)
Pin Descriptions
Pin No.
1
2
3
4
5
6
7
8
Pin Symbol
COMP
R
T
PGND
SGND
SW
V
IN
ENB
FB
Pin Description
Pin for connecting an error amplifier phase compensation resistor and capacitor.
Oscillation frequency setting pin for connecting a resistor to the internal oscillation
circuit. Connecting 120 kΩ to this pin operates the oscillation circuit at 550 kHz (typ.).
Power ground
Signal ground
Switching pin. A P-channel MOSFET is connected between the V
IN
and SW pins.
The peak switch current corresponding to the voltage that is generated at the COMP pin
flows through the power MOSFET. The rating of this peak switch current is 1.0 A (min).
Input pin. This pin is placed in the standby state if V
ENB
= low. 1
μA
or lower operating current
Enable pin. This pin is connected to the CMOS inverter. Applying 3.5 V or higher (@ V
IN
= 5 V)
to this pin starts the internal circuit to perform switching control.
Output voltage feedback pin. This is connected to the internal error amplifier, which is supplied
with a reference voltage of 0.8 V (typ.).
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2004-09-10
TB7100F
Timing Chart
OSC
0
I
OUT
0
V
OUT
0
V
COMP
0
The peak switch current is determined
according to the VCOMP.
I
L
0
V
SW
0
TON
T
Overheat state operation
OSC
0
Tch increase
T
ch
Hysteresis: 25°C (typ.)
V
SW
Low Voltage operation
V
IN
0
OSC
0
V
SW
Hysteresis: 0.1 V (typ)
0
OSC
: Internal oscillator output voltage
I
OUT
: Load current
V
OUT
: Output voltage
V
COMP
: COMP pin voltage
I
L
: Inductor current
: SW pin voltage
V
SW
V
IN
: Input pin voltage
T
ch
: Channel temperature
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2004-09-10
TB7100F
Maximum Ratings (Ta = 25°C)
Characteristics
Input voltage
Switch pin voltage
Feedback pin voltage
Enable pin voltage
Input-enable pin voltage
Power dissipation (Note 1)
Operating temperature
Channel temperature
Storage temperature
Symbol
V
IN
V
SW
V
FB
V
ENB
V
ENB
-V
IN
P
D
Topr
T
ch
T
stg
Rating
-0.3½6
-0.3½6
-0.3½6
-0.3½6
V
ENB
-V
IN
<0.3
0.7
-40½85
150
-55½150
Unit
V
V
V
V
V
W
℃
°C
°C
Thermal Resistance Characteristic
Characteristics
Thermal resistance, channel and ambient
(Note 1)
Glass epoxy board
Material : FR-4
25.4
×
25.4
×
0.8
(Unit: mm)
Symbol
R
th (ch-a)
Max
178.6 (Note 1)
Unit
°C /W
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2004-09-10
TB7100F
Electrical Characteristics (unless otherwise specified: Ta = 25°C and V
IN
= 3 to 5.5 V)
Characteristics
Operating supply voltage
Load current
Operating current
Standby current
Enable pin threshold voltage
Enable pin input current
Feedback pin current
Feedback pin voltage
Feedback pin line regulation
High-side on-state resistance
High-side leakage current
Oscillation frequency
Error amplifier conductance
Peak switch current
Undervoltage
protection
Overheat
protection
Detection
Hysteresis
Detection
Hysteresis
Symbol
V
IN(OPR)
I
OUT
I
IN
I
IN(STBY)
V
IH
V
IL
I
IH
I
FB
V
FB
ΔV
FB(LINE)
Test
circuit
－
－
－
－
－
－
Test condition
－
－
V
IN
= 5 V, V
ENB
= 5 V, V
FB
= 0.7 V
R
T
= 120 kΩ
V
IN
= 5 V, V
ENB
= 0 V, V
FB
= 0.9 V
V
IN
= 5 V
V
IN
= 5 V
V
IN
= 5 V, V
ENB
= 5 V
Min
3
－
－
－
3.5
－
－
-1
0.776
－
－
－
－
－
1.0
2.3
－
125
－
Typ.
5
－
570
－
－
－
－
－
0.8
1.6
0.27
－
550
800
1.5
2.5
0.1
145
25
Max
5.5
700
750
1
－
1.5
20
1
0.824
5
0.6
-1
－
－
－
2.7
－
－
－
Unit
V
mA
μA
μA
V
V
μA
μA
V
mV/V
Ω
μA
kHz
μS
－
－
－
－
－
－
－
－
－
－
－
－
－
V
IN
= V
ENB
= 3 V½5 V
V
IN
= 5 V, V
ENB
= 5 V, I
SW
= - 0.5
A
V
IN
= 5 V, V
ENB
= 0 V, V
SW
= 0 V
V
IN
= 5 V, V
ENB
= 5 V, R
T
= 120 k
Ω
V
IN
= 5 V, V
ENB
= 5 V
I
COMP
=
±20μA
－
－
－
－
－
R
DS(ON)
I
LEAK
f
OSC
g
m
I
SW(PEAK)
V
UV
ΔV
UV
T
SD
ΔT
SD
A
V
V
℃
℃
5
2004-09-10
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