Linear Technology LT1306 Datasheet

FEATURES

LOAD CURRENT (mA)

1

60

EFFICIENCY (%)

80

85

90

10 100 1000

1306 TA01

75

70

65

VIN = 4.2V

VIN = 3.6V

VIN = 2.6V

VO = 5V
L1 = 10µH
(FIGURE 1)

■

Output Disconnected from Input During Shutdown

■

Output Voltage Remains Regulated
When VIN > V

■

Controlled Input Current During Start-Up

■

300kHz Current Mode PWM Operation

■

Can Be Externally Synchronized

■

Internal 2A Switches

■

Operates with VIN as Low as 1.8V

■

Automatic Burst Mode Operation at Light Loads

■

Quiescent Current: 160µA

■

Shutdown Current: 9µA Typ

OUT

U

APPLICATIO S

■

Satellite Phones

■

Portable Instruments

■

Personal Digital Assistants

■

Palmtop Computers

, LTC and LT are registered trademarks of Linear Technology Corporation.

Burst Mode is a trademark of Linear Technology Corporation.

LT1306

Synchronous, Fixed Frequency

Step-Up DC/DC Converter

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DESCRIPTIO

The LT®1306 is a fully integrated, fixed frequency syn­chronous boost converter capable of generating 5V at 1A
from a Li-Ion cell. The device contains both the main
power switch and synchronous rectifier on chip and
automatically disconnects the output from the input in
shutdown, eliminating the need for external load discon­nect circuitry. Additionally, the output remains regulated
when VIN exceeds V
down converter functions to be easily realized using a
single inductor.

The internal 300kHz oscillator of the LT1306 can be easily
synchronized to an external clock from 425kHz to 500kHz.
This allows switching harmonics to be tightly controlled
and eliminates any beat frequencies that may result from
a multifrequency system. The LT1306 automatically shifts
into power saving Burst ModeTM operation at light loads.
At heavy loads the LT1306 operates in fixed frequency
current mode. No-load quiescent current is 160µA and
reduces to 9µA in shutdown mode.

The LT1306 is available in an SO-8 package.

, allowing difficult step-up/step-

OUT

TYPICAL APPLICATION

D1

L1

118k

C

10µH

V

V

R3

Z

SW

IN

LT1306

C

1-CELL

Li-Ion

+

C

IN1

22µF

C

IN2

0.1µF

68nF

Figure 1. Single Li-Ion Cell to 5V Converter

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C1

1µF

C

P

68pF

+

CAP

OUTS/S

GND

Efficiency

5V

R1

FB

768k

R2
249k

+

C

O1

220µF

1306 F01

1A

C

O2

1µF
C

: AVX TAJC226M010

IN1

: AVX TPSE227M010R0100

C

O1

, CO2: CERAMIC

C

IN1

C1: AVX TAJA105K020
D1: MMBD914LT1
L1: CTX10-2

1

LT1306

1

2

3

4

8

7

6

5

TOP VIEW

S8 PACKAGE

8-LEAD PLASTIC SO

V

C

FB

V

OUT

GND

S/S

V

IN

CAP

SW

WW

W

ABSOLUTE MAXIMUM RATINGS

U

U

W

PACKAGE/ORDER INFORMATION

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(Note 1)

VIN Voltage ............................................................. 10V

S/S Voltage ............................................................... 7V

ORDER PART

NUMBER

FB Voltage .............................................................. 10V

V

Voltage.......................................................... 5.5V

OUT

LT1306ES8

Junction Temperature.......................................... 125°C

Operating Temperature Range (Note 2) .. – 40°C to 85°C

Storage Temperature Range ................. –65°C to 150°C

S8 PART MARKING

Lead Temperature (Soldering, 10 sec)..................300°C

T

= 125°C, θJA = 90°C/W

JMAX

Consult factory for Industrial and Military grade parts.

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at TA = 25°C. VIN = 2.5V, V

PARAMETER CONDITIONS MIN TYP MAX UNITS

Reference Voltage Measured at the FB Pin ● 1.22 1.24 1.26 V
Reference Line Regulation 1.8V ≤ VIN ≤ 7V 0.002 0.1 %/V
FB Input Bias Current VFB = V
Error Amplifier Transconductance ∆I = ±0.2µA 80 150 220 µΩ
Error Amplifier Output Source Current VFB = 1V, VC = 0.8V 5 7.5 11 µA
Error Amplifier Output Sink Current VFB = 1.5V, VC = 0.8V 5 7.5 11 µA
Error Amplifier Output Clamp Voltage VFB = 1V 1.18 1.28 1.38 V
VIN Undervoltage Lockout Threshold 1.55 1.8 V
Idle Mode Output Leakage Current VFB = 1.5V, V
Output Source Current in Shutdown V
Switching Frequency 1.8V ≤ VIN ≤ 7V, 0°C ≤ TA ≤ 85°C ● 260 310 415 kHz

Maximum Duty Cycle VFB = 1V, 0°C ≤ TA ≤ 85°C8090%

Switch Current Limit Duty Cycle = 0.1 (Note 3) 2.3 A

Burst Mode Operation Switch Current Limit 250 mA
Switch V

CESAT

Rectifier V
Stepdown Mode Rectifier Voltage V

Switch and Rectifier Leakage Current V

CESAT

OUT

1.8V ≤ V

V

FB

Duty Cycle = 0.8 (Note 3) 2.0 A

ISW = 2A 0.45 0.575 V
ISW = 2A 0.49 0.675 V

OUT

V

OUT

OUT

The ● denotes the specifications which apply over the full operating

= VIN, VC open unless otherwise noted.

S/S

REF

= 5.5V, VSW = 1.7V ● 615 µA

OUT

= 0V, VIN = VSW = 7V, V

≤ 7V, TA = –40°C 225 305 390 kHz

IN

= 1V, TA = –40°C6580%

= 0V, ISW = 1A 0.3 + V
= 2.2V, ISW = 1A 1.3 1.8 V

= 0V, VIN = VSW = 7V, V

= 7.2V, V

CAP

= 7.2V, V

CAP

= 0V ● –3 µA

S/S

= 0V ● 0.1 20 µA

S/S

● 10 25 nA

IN

1306

0.7 + V

–1

IN

V

2

LT1306

V

S/S

(V)

5
4
3
2
1

0
–1
–2
–3
–4
–5

I

S/S

(µA)

1306 • G03

054321

TA = –40°C

TA = 85°C

TA = 25°C

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at TA = 25°C. VIN = 2.5V, V

The ● denotes the specifications which apply over the full operating

= VIN, VC open unless otherwise noted.

S/S

PARAMETER CONDITIONS MIN TYP MAX UNITS

S/S Pin Current V

= V

S/S

IN

= 0V –3 µA

V

S/S

6 µA

Shutdown Pin Input High Voltage 1.2 V
Shutdown Pin Input Low Voltage 0.45 V

Shutdown Delay 12 20 50 µs
Synchronization Frequency Range 425 500 kHz
Operating Supply Current 4.5 8 mA
Quiescent Supply Current V
Shutdown Supply Current V
CAP Pin Leakage Current VIN = V
Output Boost-to-Stepdown Threshold V

= VIN, VFB = 1.5V ● 160 250 µA

S/S

= 0V 9 16 µA

S/S

CAP

= 7V, V

= 2.5V, ISW = 0 ● 10 µA

S/S

IN

Output Stepdown-to-Boost Threshold VIN – 0.1 V

Note 1: Absolute Maximum Ratings are those values beyond which the life
to the device may be impaired.

Note 2: The LT1306E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating

temperature range are assured by design, characterization and correlation
with statistical process controls.

Note 3: Switch current limit guaranteed by design/correlation to static
tests.

V

UW

TYPICAL PERFORMANCE CHARACTERISTICS

Reference Voltage vs
Temperature

1.239

1.238

1.237

1.236

1.235

1.234

1.233

REFERENCE VOLTAGE (V)

1.232

1.231
–40

040

–20 20 60 100

TEMPERATURE (°C)

Maximum Load Current vs
Input Voltage

1.5

VO = 3.3V

1.0

(A)

LOADMAX

I

0.5

L = 10µH

= 125°C

T

J

0

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
V

VO = 5V

(V)

IN

T

A

T

A

= 25°C
= 50°C

1306 • G01

S/S Pin Current vs S/S Pin Voltage

80

1306 • G02

3

LT1306

UW

TYPICAL PERFORMANCE CHARACTERISTICS

Shutdown Supply Current vs
Input Voltage

40

35

30

25

20

TA = –40°C

15

SUPPLY CURRENT (µA)

10

5

0

4681012

2

INPUT VOLTAGE (V)

Oscillator Frequency Line
Regulation

320

315

310

FREQUENCY (kHz)

305

300

135 10

24

0

VIN (V)

TA = 25°C

TA = 85°C

1306 • G04

9876

1306 • G07

S/S Pin Current vs Temperature

5.0

V

= 2.5V

S/S

2.5

0

S/S CURRENT (µA)

V

= 0V

S/S

–2.5

–40

02040 8060 100

–20

TEMPERATURE (°C)

Frequency vs Temperature

315
310
305
300
295
290
285

FREQUENCY (kHz)

280
275
270
265

–40

0

–20

TEMPERATURE (°C)

40

20

Idle-Mode Supply Current vs
Temperature

155

150

145

140

IDLE-MODE SUPPLY CURRENT (µA)

135

–20 20 60 100

1306 • G05

–40

040

TEMPERATURE (°C)

80

1306 • G06

Maximum Duty Ratio

95

VIN = 2.5V

90

85

80

75

DUTY RATIO (%)

70

65

60

–40

80

1306 • G08

100

60

–20 0

TEMPERATURE (

40 80 100

20 60

°C)

1306 • G09

Maximum Allowable Rise Time of
Synchronizing Pulse

600

500

400

300

200

MAXIMUM RISE TIME (ns)

100

0

1

1.5 2.0 2.5 3.0

SYNCHRONIZING PULSE AMPLITUDE (V)

4

1306 • G10

3.5

Current Limit vs Duty Cycle

3.0

TA = 25°C

2.8

2.6

2.4

CURRENT LIMIT (A)

2.2

2.0

10 30

0

20

40

DUTY CYCLE (%)

70

50 90

80

60

1306 • G11

Switch Saturation Voltage
vs Current

0.7

0.6

0.5

0.4

0.3

0.2

SWITCH VOLTAGE (V)

0.1

0

0

TA = 25°C

TA = 85°C

0.5 1.0 2.0 2.5
SWITCH CURRENT (A)

TA = –40°C

1.5

1306 • G12

UW

TYPICAL PERFORMANCE CHARACTERISTICS

Rectifier Saturation Voltage
vs Current

0.7

0.6

0.5

0.4

0.3

TA = –40°C

TA = 85°C

TA = 25°C

Stepdown-Mode Rectifier Voltage
vs Current

1.90

VIN = 6V

= 5V

V

OUT

1.85

= 25°C

T

A

1.80

1.75

1.70

Continuous-Conduction Mode
Switching Waveforms in Boost
Operation

V

SW

5V/DIV

I

L

0.5A/DIV

LT1306

0.2

RECTIFIER VOLTAGE (V)

0.1

0

0.5 1.0 2.0 2.5

0

RECTIFIER CURRENT (A)

Start-Up to Shutdown Transient
Response*

V

S/S

5V/DIV

V

SW

5V/DIV

I

L

2A/DIV

V

O

5V/DIV

= 2.5V

V

IN

1ms/DIV

1.5

1306 • G13

1.65

RECTIFIER VOLTAGE (V)

1.60

1.55

0.5 1.0 2.0

0

RECTIFIER CURRENT (A)

Continuous-Conduction Mode
Switching Waveforms in
Stepdown Mode

V

SW

5V/DIV

I

L

0.5V/DIV

V

O

50mV/DIV

AC

VIN = 6V
V

= 5V

O

2µs/DIV

1.5

1306 • G14

0.1V/DIV

LOAD

CURRENT

0.5A/DIV

INDUCTOR

CURRENT

1A/DIV

OUTPUT

0.1V/DIV

V

O

AC

V
V

= 4.2V

IN

= 5V

O

2µs/DIV

Transient Response of the
Converter in Figure 1 with a
50mA to 800mA Load Step

DC

AC

VIN = 3.6V
V

= 5V

O

1ms/DIV

*Notice that the Input Start-Up Current is well Controlled and the

Output Voltage Falls to Zero in Shutdown.

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