Linear Technology LT1109CS8-5, LT1109CS8-12, LT1109CN8-12, LT1109CN8, LT1109CZ-5 Datasheet

LT1109

Micropower Low Cost

DC/DC Converter

Adjustable and Fixed 5V, 12V

FEATURES

■Uses Off-the-Shelf Inductors

■Only 33μH Inductor Required

■Low Cost

■3-Lead TO-92, SO8, or 8-Pin DIP

■Adjustable or Fixed 5V or 12V Output

■120kHz Oscillator

■Only Three External Components Required

■320μA IQ

■1.6V Minimum Start-Up Voltage

■Logic Controlled Shutdown

APPLICATIOUS

■Flash Memory VPP Generators

■3V to 5V Converters

■5V to 12V Converters

■Disk Drives

■PC Plug-In Cards

■Peripherals

■Battery-Powered Equipment

DESCRIPTIOU

The LT1109 is a simple step-up DC/DC converter. Available in 8-pin SO, 3-lead TO-92 (fixed output only) or miniDIP packages, the devices require only three external components to construct a complete DC/DC converter. Current drain is just 320μA at no load, making the device ideal for cost-sensitive applications where standby current must be kept to a minimum.

The LT1109-5 can deliver 5V at 100mA from a 3V input and the LT1109-12 can deliver 12V at 60mA from a 5V input. The 8-pin versions also feature a logic controlled SHUTDOWN pin that turns off the oscillator when taken low. The gated-oscillator design requires no frequency compensation components. The high frequency 120kHz oscillator permits the use of small surface mount inductors and capacitors. For a 5V to 12V at 120mA converter, see the LT1109A. Foa a 5V to 12V at 200mA converter with 20μA shutdown current, see the LT1301.

TYPICAL APPLICATIOU

All Surface Mount	Output Voltage	Flash Memory Program Output
Flash Memory VPP Generator

L1

15

MBRS120T3

VIN = 5V

VOUT

33μH

5V/DIV

12

3

(V)

OV

SW

1

8

VOUT

VOLTAGE

5V

9

5V/DIV

80mA

VIN

V

IN

SENSE

12V

SHUTDOWN

LT1109CS8-12

+

OUTPUT

6

7

C1**

1ms/DIV

SHUTDOWN*

22μF

LT1109 • TA02

GND

16V

3

4

SHUTDOWN

PROGRAM

* 8-PIN PACKAGE ONLY

LT1109 • TA01

0

10

20

30

40

50

60

70

80

90

100

0

L1 = SUMIDA CD54-330LC (IOUT = 80mA)

COILTRONICS CTX33-1 (80mA)

OUTPUT CURRENT (mA)

MURATA-ERIE LQH4N330K=(I50mA)

LT1109 • TPC01

OUT

ISI LCS2414-330K (IOUT = 50mA)

**C1 = MATSUO 267M1602226 OR EQUIVALENT

1

LT1109

ABSOLUTE WAXIWUW RATIUGS

(Voltages Referred to GND Pin)
Supply Voltage (VOUT) ..............................	– 0.4V to 20V
SW Pin Voltage ..........................................	– 0.4V to 50V
SHUTDOWN Pin Voltage.........................................	6.0V
Maximum Power Dissipation .............................	300mW

Operating Temperature Range .....................	0°C to 70°C
Storage Temperature Range .................	– 65°C to 150°C
Lead Temperature (Soldering, 10 sec.).................	300°C
Switch Current ........................................................	1.2A

PACKAGE/ORDER IUFORWATIOU

TOP VIEW

TOP VIEW

BOTTOM VIEW

3

2

1

VIN

1

8

SENSE

VIN

1

8

SENSE

VOUT

SW

GND

NC

2

7

SHUTDOWN

NC

2

7

SHUTDOWN

NC

SW

3

6

NC

SW

3

6

GND

NC

GND

NC

4

5

4

5

Z PACKAGE

N8 PACKAGE

S8 PACKAGE

8-LEAD PLASTIC DIP

LT1109 • PO102

8-LEAD PLASTIC SOIC

LT1109 • PO103

3-LEAD TO-92 PLASTIC LT1109 • POI01

TJMAX = 100°C, θJA = 130°C/W

TJMAX = 100°C, θJA = 150°C/W

TJMAX = 100°C, θJA = 160°C/W

ORDER PART

ORDER PART

S8 PART

ORDER PART

NUMBER

NUMBER

MARKING

NUMBER

LT1109CN8

LT1109CS8

1109

LT1109CZ-5

LT1109CN8-5

LT1109CS8-5

10905

LT1109CZ-12

LT1109CN8-12

LT1109CS8-12

10912

ELECTRICAL CHARACTERISTICS TA = 25°C, VIN = 3V (LT1109CN8, LT1109CS8), unless otherwise specified.

SYMBOL	PARAMETER	CONDITIONS		MIN	TYP	MAX	UNITS
IQ	Quiescent Current	Switch Off	●		320	550	μA
	Minimum Start-Up Voltage			1.6			V
	at VOUT Pin (Z Package)
VIN	Input Voltage (N8, S8 Package)		●	3			V
	Comparative Trip Point Voltage	LT1109	●	1.20	1.25	1.30	V
VOUT	Output Voltage	LT1109-5; 3V ≤ VIN ≤ 5V	●	4.75	5.00	5.25	V
		LT1109-12; 3V ≤ VIN ≤ 12V	●	11.52	12.00	12.55	V
	Comparator Hysteresis	LT1109	●		8	12.5	mV
	Output Voltage Ripple	LT1109-5	●		25	50	mV
		LT1109-12	●		60	120	mV
fOSC	Oscillator Frequency			100	120	140	kHz
			●	90		150	kHz
tON	Switch ON Time			3.3	4.2	5.3	μs
			●	3.0		5.5	μs
DC	Duty Cycle	Full Load	●	45	50	60	%
VCESAT	Switch Saturation Voltage	ISW = 500mA			0.4	0.7	V
		LT1109-5: VIN = 3V; LT1109-12: VIN = 5V	●		0.5	0.8	V

2

LT1109

ELECTRICAL CHARACTERISTICS TA = 25°C, VIN = 3V (LT1109CN8, LT1109CS8), unless otherwise specified.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Switch Leakage Current

VSW = 12V

1

10

μA

VIH

N8, S8 Package

2.0

V

SHUTDOWN

Pin High

●

VIL

Pin Low

N8, S8 Package

0.8

V

SHUTDOWN

●

IIH

N8, S8 Package, V

= 4V

10

μA

SHUTDOWN

Pin Input Current

●

SHUTDOWN

IIL

Pin Input Current

N8, S8 Package, V

= 0V

20

μA

SHUTDOWN

●

SHUTDOWN

The ● denotes the specifications which apply over the full operating temperature range.

TYPICAL PERFORWAUCE CHARACTERISTICS

			Oscillator Frequency							Oscillator Frequency
	160									130
	140								(kHz)	128
										126
(kHz)FREQUENCY	120								FREQUENCYOSCILLATOR	124
										122
	100									120
										118
	80									116
										114
	60									112
										110

–50	–25	0	25	50	75	100	0	2	4	6	8	10	12	14	16	18	20
		TEMPERATURE (°C)			LT1109 • TPC02					INPUT VOLTAGE (V)
															LT1109 • TPC03

SWITCH ON TIME (μs)

Switch ON Time

7

6

5

4

3	–25	0	25	50	75	100
–50

TEMPERATURE (°C)

LT1109 • TPC04

DUTY CYCLE (%)

	Duty Cycle														Switch Saturation Voltage
70															700
65															600									ISW = 500mA
60
															500
55														(mV)
															400
50
														CESAT300
45
														V
40															200
															100
35
															0
30
–50			–25		0		25		50		75		100		–50		–25		0	25		50			75		100
					TEMPERATURE (°C)														TEMPERATURE (°C)
											LT1109 • TPC05														LT1109 • TPC06

VCESAT (V)

Switch Saturation Voltage

1.2

VIN = 5V 1.0 TA = 25°C

0.8

0.6

0.4

0.2

0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

SWITCH CURRENT (A)

LT1109 • TPC07

3