TOKO TK65020MTL Datasheet

ADVANCED INFORMATION

V

IN

GND

SW

NC

V

OUT

CONTROL

CIRCUIT

OSCILLATOR

Vref UVLO

20P

TK65020

ADVANCED

INFORMATION

FEATURES

■ Guaranteed 0.9 V Operation

■ Very Low Quiescent Current

■ Internal Bandgap Reference

■ High Efficiency MOS Switching

■ Low Output Ripple

■ Laser-Trimmed Output Voltage

■ Laser-Trimmed Oscillator

■ Undervoltage Lockout

■ Regulation by Pulse Burst Modulation (PBM)

DESCRIPTION

The TK65020 low power step-up DC-DC converter is
designed for portable battery-powered systems, capable
of operating from a single battery cell down to 0.9 V. The
TK65020 provides the power switch and the control circuit
for a boost converter. The converter takes a DC input and
boosts it up to a regulated 2.5 V output .

STEP-UP VOLTAGE CONVERTER

APPLICATIONS

■ Battery Powered Systems

■ Cellular Telephones

■ Pagers

■ Personal Communications Equipment

■ Portable Instrumentation

■ Portable Consumer Equipment

■ Radio Control Systems

taken to achieve reliability through the use of Oxide,
double Nitride passivation. The TK65020 is available in a
miniature 6-pin SOT-23L-6 surface mount package.

For other output levels, please refer to the TK651xx and
TK652xx Toko series of step-up converters.

The output voltage is laser-trimmed. An internal
Undervoltage Lockout (UVLO) circuit is utilized to prevent

TK65020

the inductor switch from remaining in the “on” mode when
the battery voltage is too low to permit normal operation.

V

IN

NC

Pulse Burst Modulation (PBM) is used to regulate the
voltage at the V

pin of the IC. PBM is the process in

OUT

which an oscillator signal is gated or not gated to the switch
drive each period. The decision is made just before the

GND

SW

GND

V

OUT

start of each cycle and is based on comparing the output
voltage to an internally-generated bandgap reference.
The decision is latched, so the duty ratio is not modulated
within a cycle. The average duty ratio is effectively
modulated by the “bursting” and skipping of pulses which

BLOCK DIAGRAM

can be seen at the SW pin of the IC. Special care has been

ORDERING INFORMATION

TK65020MTL

Tape/Reel Code

TAPE/REEL CODE

TL: Tape Left

January 1999 TOKO, Inc. Page 1

TK65020

ADVANCED INFORMATION

ABSOLUTE MAXIMUM RATINGS

All Pins Except SW and GND .................................... 6 V

SW Pin ....................................................................... 9 V

Power Dissipation (Note 1) ................................. 400 mA

Storage Temperature Range ................... -55 to +150 °C

Operating Temperature Range ...................-20 to +80 °C

Junction Temperature ...........................................150 °C

TK65020 ELECTRICAL CHARACTERISTICS

Over operating temperature range and supply voltage range, unless otherwise specified.

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

V

NI

I

)Q(B

V(I

)VotnitnerruCtnecseiuQ

NI

)VotnitnerruCtnecseiuQ

V(I

TUO

f

CSO

∆f

/∆T

CSO

D

CSO

V
∆V

/∆T

TUO

∆V
∆V

R

)NO(WS

FFE)4,3setoN(ycneiciffEretrevnoC

egatloVylppuS09.006.1V

V

NI

)3etoN(tnerruCyrettaBdaoLoN

T

A

V

niP

NI

niPVNI,V3.1=I

TUO

ycneuqerFrotallicsOlanretnIV

rotallicsOfooitaRytuDemit-nOT

)GER(TUO

VfodlohserhTnoitalugeR

TUO

VfoytilibatSerutarepmeT

)DAOL(TUO

)ENIL(TUO

VfonoitalugeRdaoL

VfonoitalugeReniL

)GER(TUO

)GER(TUO

niPWSfoecnatsiser-nOT

NI

T

A

NI

rotallicsOfoytilibatSerutarepmeTV

NI

A

T

A

V

)GER(TUO

NI

V

NI

∆V

NI

≥ 4.20.1V

A

V

NI

,V3.1=I

TUO

C°52=

,V3.1=I

TUO

C°52=

TUO

,V3.1=I

TUO

,V3.1=
C°52=540555%
C°52=83.205.285.2V

,V3.1=I

TUO

,V3.1=I

TUO

V52.0=

,V3.1=I

TUO

,Am0=

,Am0=

1426Aµ

1102Aµ

Am0=2102Aµ
Am0=0738201zHk

gnippikSesluPoN

1.0C°/%

Am0=001Vm

Am4ot0=005Vm

02-03Vm

,Am6=

lioCFD3,Hµ59=L

67%

V

VLU

ImumixaM

I

)XAM(TUO

Note 1: Derate at 0.8 mW/oC for operation above TA = 25 oC ambient temperature, when heat conducting copper foil path is maximized on the printed

circuit board. When this is not possible, a derating factor of 1.6 mW/ °C must be used.

TUO

)4,2setoN(

egatloVtuokcoLegatlovrednUT

A

V

NI

T,V1.1=

)5etoN(,C°52=54.097.0V

A

,C°52=

lioCFD3,Hµ59=L

V

NI

retrevnoCrof

V

NI

T,V3.1=

A

,C°52=

lioCFD3,Hµ59=L

T,V1.1=

A

,C°52=

lioC37D,Hµ93=L

V

NI

T,V3.1=

A

,C°52=

lioC37D,Hµ93=L

50.8Am

90.51Am

8.91Am

0.83Am

Page 2 January 1999 TOKO, Inc.

ADVANCED INFORMATION

TK65020

Inductor L: Toko A682AE-014 or equivalent
Diode D: LL103A or equivalent
Capacitors CN:CO:CB: Panasonic TE series,
ECS-TOJY106R

I

B

V

IN

BENCH TEST CIRCUIT

I(VIN)

V

R

N

1 K

C

10 µF

L = 95 µH

C

B

10 µF

IN

GND GND

N

C

S

220 pF

1 K

R

S

NC

V

OUTIND

D

I(V

)

OUT

Note 2: Maximum load current depends on

inductor value and input voltages.

Note 3: Output ripple depends on filter

capacitor values, ESRs and the
inductor value.

Note 4: When using specified Toko inductor

and Schottky diode with VF = 0.45 V
@ 100 mA.

Note 5: Regulation not guaranteed

I

OUT

V

OUT

C

O

10 µF

The Bench Test Circuit is used most of the time to measure the typical (typ.) values in the Electrical Characteristics
section, and make the Typical Performance graphs.

Note: In measuring the oscillator frequency and the Max I

on the bench, the converter was loaded until “no pulse

OUT

skipping” mode was achieved.

FINAL TEST CIRCUIT

V

IN

GND GND

N

C

S

220 pF

R

1 K

S

I

B

V

IN

Inductor L: Toko A682AE-014 or equivalent
Diode D: LL101
Capacitors CN:CU:CD: Panasonic TE series,

C

10 µF

L = 95 µF

ECS-TOJY106R

Above is the Final Test Circuit through which each of the production parts must pass. In this test circuit, the part is tested
against the specification limits in the data sheet (the min. and max. values in the Electrical Characteristics) at room
temperature, and is rejected if the tested values are outside the minimum (min.) and maximum (max.) values.

NC

V

OUTSW

I

R

OF

15

D

++

C

U

10 µF

10 µF

OUT

V

OUT

C

D

January 1999 TOKO, Inc. Page 3

TK65020

BATTERY CURRENT

VS.

INPUT VOLTAGE

120

0 .5 1 1.5 2 2.5 3

VIN (V)

I

B

(µA)

100

60

80

40

20

0

TA = 25 °C

NO LOAD

TK65020

ADVANCED INFORMATION

TYPICAL PERFORMANCE CHARACTERISTICS

OSCILLATOR FREQUENCY VS.

TEMPERATURE

95

90

(kHz)

85

OSC

f

80

75

-50 0 50 100
TEMPERATURE (°C)

OUTPUT VOLTAGE

2.6

L = 95 µH
TOKO P/N: A682AE-014
(3DF SERIES)

LOAD CURRENT

TA = 25 °C

2.5

(V)

OUT

V

2.4

2.3

V

IN

= 0.9 V

1.3 V

1.1 V

1.6 V

VS.

OUTPUT REGULATION VOLTAGE

TEMPERATURE

2.60

2.55

(V)

2.50

OUT(REG)

V

2.45

2.40

-50 0 50 100
TEMPERATURE (°C)

OUTPUT VOLTAGE

2.6

L = 100 µH
TOKO P/N: A636CY-101M
(D73 SERIES)

LOAD CURRENT

TA = 25 °C

2.5

(V)

OUT

V

2.4

2.3

V

IN

= 0.9 V

1.3 V

1.1 V 1.6 V

VS.

VS.

2.6

L = 39 µH
TOKO P/N: A636CY-390M
(D73 SERIES)

2.5

(V)

2.4

OUT

V

2.3

OUTPUT VOLTAGE

LOAD CURRENT

TA = 25 °C

V

IN

= 0.9 V

1.3 V

1.1 V 1.6 V

VS.

2.2
1 10 100

EFFICIENCY

90

L = 95 µF
Toko P/N: A682AE-014
(3DF SERIES) SMALL COIL

85

80

75

VIN = 0.9 V

EFF (%)

70

65

60

0.1 1 10 100

Page 4 January 1999 TOKO, Inc.

I

(mA)

OUT

VS.

LOAD CURRENT

TA = 25 °C

1.1 V

I

(mA)

OUT

1.3 V

1.6 V

2.2
1 10 100

I

(mA)

OUT

EFFICIENCY

90

L = 100 µF
Toko P/N: 636CY-101M
(D73 SERIES) LARGER COIL

85

80

V

= 0.9 V

IN

VS.

LOAD CURRENT

TA = 25 °C

1.1 V

75

EFF (%)

70

65

60

0.1 1 10 100
I

(mA)

OUT

1.3 V

1.6 V

2.2
1 10 100

I

(mA)

OUT

MAXIMUM OUTPUT CURRENT

INDUCTOR VALUE (µH)

50

NO PULSE
SKIPPING

40

(mA)

30

20

OUT(MAX)

I

1.1 V

MODE
TA = 25 °C

10

VIN = 0.9 V

0

0 40 80 120 160

INDUCTOR VALUE (µH)

VS.

1.3 V

ADVANCED INFORMATION

SINGLE-CELL APPLICATION

TK65020

The TK65020 is a boost converter control IC with the
power MOSFET switch built into the device. It operates
from a single battery cell and steps up the output voltage
to a regulated 2.5 V. The device operates at a fixed
nominal clock frequency of 83 kHz.

In its simplest form, a boost power converter using the
TK65020 requires only three external components: an
inductor, a diode, and a capacitor.

The analysis is easier to follow when referencing the
simple boost circuit below.

V

IN

GND GND

NC

V

OUTSW

V

+

OUT

FIGURE 1: SIMPLE BOOST CONVERTER

and Noise Considerations” section) can be determined if
needed or desired.

The TK65020 runs with a fixed oscillator frequency and it
regulates by applying or skipping pulses to the internal
power switch. This regulation method is called Pulse Burst
Modulation (PBM).

ANALYSIS OF SWITCHING CYCLE

I

PEAK

di/dt = VIN/ L

t (on)

di/dt = - (V

t (off)

+ Vf - VIN)/ L

OUT

t (deadtime)

THEORY OF OPERATION

The converter operates with one terminal of an inductor
connected to the DC input and the other terminal connected
to the switch pin of the IC. When the switch is turned on, the
inductor current ramps up. When the switch is turned off (or
“lets go” of the inductor), the voltage flies up as the inductor
seeks out a path for its current. A diode, also connected to
the switching node, provides a path of conduction for the
inductor current to the boost converter’s output capacitor.
The TK65020 monitors the voltage of the output capacitor
and has a 2.5 V threshold at which the converter switching
becomes deactivated. So the output capacitor charges up
to 2.5 V and regulates there, provided that no more current
is drawn from the output than the inductor can provide. The

primary task, then, in designing a boost converter with
the TK65020 is to determine the inductor value (and its
peak current rating to prevent inductor core saturation
problems) which will provide the amount of current
needed to guarantee that the output voltage will be
able to maintain regulation up to a specified maximum
load current. Secondary necessary tasks also include

choosing the diode and the output capacitor. Then the
snubber and filtering component values (consult the “Ripple

Above is the input or inductor current waveform over a
switching cycle.

From an oscillator standpoint, the switching cycle consists
of only an on-time and an off-time. But from an inductor
current standpoint, the switching cycle breaks down into
three important sections: on-time, off-time, and deadtime.
The on-time of the switch and the inductor current are
synonymous. During the on-time, the inductor current
increases. During the off-time, the inductor current
decreases as it flows into the output. When the inductor
current reaches zero, that marks the end of the inductor
current off-time. For the rest of the cycle, the inductor
current remains at zero. Since no energy is being either
stored or delivered, that remaining time is called “deadtime.”
This mode of the inductor current decaying to zero every
cycle is called “discontinuous mode.” In summary, energy
is stored in the inductor during on-time, delivered to the
output during off-time, and remains at zero during deadtime.

January 1999 TOKO, Inc. Page 5