Datasheet LT1106 Datasheet (Linear Technology)

LT1106

LOAD CURRENT (mA)

1

70

EFFICIENCY (%)

72

74

76

78

86

10 100

LT1106 • TA02

80

82

84

VIN = 5V

VIN = 5V

VIN = 3.3V

VIN = 3.3V

D1 = MBR0530
D1 = 4 BAT54Cs
IN PARALLEL

Micropower Step-Up

DC/DC Converter for

PCMCIA Card Flash Memory

EATU

F

■

60mA Output Current at 12V from 3V Supply

■

Shutdown to 10µA

■

Programmable 12V or 5V Output

■

Up to 85% Efficiency

■

Quiescent Current: 750µA

■

Low V

■

Uses Low Value, Thin, Surface Mount Inductors

■

Ultra-Thin 20-Lead TSSOP Package

PPLICATI

A

■

PCMCIA Card Flash Memory VPP Generator

■

Portable Computers

■

Portable Instruments

■

DC/DC Converter Module Replacements

S

RE

Switch: 300mV at 0.5A Typical

CESAT

U

O

S

DUESCRIPTIO

The LT®1106 is the industry’s first DC/DC converter
designed for use on Type I and Type II PCMCIA cards. The
device senses the VPP1 and VPP2 lines at the PCMCIA
socket and generates a regulated 12V, 60mA program­ming supply if the socket does not provide it. Internal logic
simplifies the interface to PCMCIA card microcontrollers.
One input selects a 12V or 5V regulated output, while
another input controls micropower shutdown. Two logic
outputs indicate when the selected programming voltage
is valid and whether the input supply is 3.3V or 5V.

The regulator features Burst ModeTM operation with a 0.5A,
300mV switch for efficiency up to 85%. High frequency
500kHz switching permits the use of small value, flat
inductors that fit neatly on PCMCIA cards. The device
requires just 1µF of output capacitance.

Quiescent current is 750µA which drops to 350µA when
the card runs off the socket supply. The shutdown pin
reduces supply current to only 10µ A. The device includes
a soft start feature which limits supply current transients
when the card is inserted into a hot socket.

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

Burst Mode is a trademark of Linear Technology Corporation.



V

CC

3.3V/5V

+

VPP1

VPP2

DALE ILS-3825-01 OR

*

COILTRONICS CTX02-11238-3


MOTOROLA MBR0530

**

U

O

A

PPLICATITYPICAL

12V, 60mA Flash Memory Programming Supply

4.7µF
TANT
ALUM

0.1µF

0.1µF

POWER ON

D

BSS84

S

0.1µF

BSS84

L1*
10µH

V

CC

VPP1

D

G1

LT1106

S

VPP2

G2

ON/OFF

VPP VALID

3/5 DETECT

SOFT START

GNDPGND

SW

AVPP

12/5

D1**

1M 0.1µF

1µF

470pF

LT1106 • TA01

12V Output Efficiency

12V/60mA

VPP VALID

3/5

1

LT1106

A

W

O

LUTEXI T

S

A

WUW

ARB

U
G

I

S

VCC Voltage............................................................... 7V

VSW Voltage............................................................ 20V

AVPP Voltage ......................................................... 20V

VPP1, VPP2 Voltage ............................................... 20V

G1, G2 Voltage ....................................................... 20V

V
V
I

LIM

Voltage......................................................... 7V

ON/OFF

Voltage ............................................................. 7V

SEL

Voltage .............................................................. 7V

Maximum Power Dissipation ............................ 500mW

Operating Temperature Range ..................... 0°C to 70°C

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

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

LECTRICAL C CHARA TERIST

E

ICS

TA = 25°C, VCC = 5V, V

/

PACKAGE

SELECT 12/5
SOFT START

V

CC

V

CC

3/5
PGND
PGND

NC

V

SW

V

SW

T

Consult factory for Industrial and Military grade parts

O

RDER I FOR ATIO

TOP VIEW

1
2
3



4



5
6
7
8
9



10

F PACKAGE

20-LEAD PLASTIC TSSOP

= 100°C, θJA = 90°C/W

JMAX

= 3V, unless otherwise noted.

ON/OFF

20
19
18
17
16
15
14
13
12
11




ON/OFF
AVPP
VPP1
VPP2
G1
G2
VPP VALID
GND
NC
V

SW

WU

ORDER PART

NUMBER

LT1106CF

U

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

I

Q

f

OSC

DC Maximum Duty Cycle ● 80 85 92 %
t

ON

V

CESAT

Quiescent Current V
Quiescent Current, Shutdown V
“Doze” Mode Current V
Input Voltage Range 2 6 V
Output Sense Voltage V

Output Referred V
Comparator Hysteresis V

Oscillator Frequency Current Limit Not Asserted 400 500 700 kHz

Switch On-Time 1.7 µs
Reference Line Regulation 2V < VIN < 6V 0.06 0.15 %/V
Switch Saturation Voltage ISW = 0.5A 230 350 mV
Switch Leakage Current VSW = 12V, Switch Off 0.1 10 µA
Switch Current Limit VIN = 5V, Soft Start Floating 450 600 900 mA

Soft Start Pin Current Soft Start Grounded 80 120 µA
Select Input Voltage Low 0.8 V
Select Input Voltage High 1.6 V
ON/OFF Input Voltage Low 0.8 V
ON/OFF Input Voltage High 1.6 V
ON/OFF Bias Current V

= 0.2V, AVPP = 12V 750 900 µA

SEL

= 0.2V 9 15 µA

ON/OFF

= 0.2V, VPP1 or VPP2 = 12V 320 µA

SEL

= 3V, VPP1 and VPP2 Floating ● 4.75 5 5.25 V

SEL

= 0.2V, VPP1 and VPP2 Floating ● 11.50 12 12.60 V

V

SEL

= 3V 15 mV

SEL

= 0.2V 35 mV

SEL

= 3V, Soft Start Floating 500 650 950 mA

V

IN

= 5V 16.0 24.0 µA

ON/OFF

= 3V 8.0 14.0 µA

V

ON/OFF

= 0V 0.1 1.1 µA

V

ON/OFF

2

LT1106

LECTRICAL C CHARA TERIST

E

ICS

TA = 25°C, VCC = 5V, V

= 3V, unless otherwise noted.

ON/OFF

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Select Pin Bias Current 0V < V

< 5V 0.1 1 µA

SEL

VPP1/VPP2 Input Sense Threshold 11.0 11.5 11.9 V
AVPP Pin Input Current 50 90 µA

= 0.2V 0.1 1 µA

V

ON/OFF

VPP1/VPP2 Pin Input Current 50 90 µA

= 0.2V 0.1 1 µA

V

ON/OFF

VPP VALID Threshold AVPP Rising (High to Low Transition) ● 11.4 12 V
VPP VALID Output Voltage Low I
VPP VALID Output Voltage High I

= 100µA 0.13 0.3 V

SINK

= 2.5µA 4 4.5 V

SOURCE

3/5 Comparator Threshold ● 3.6 3.75 4.2 V
3/5 Comparator Output High I
3/5 Comparator Output Low I

= 50µA 3.65 3.8 V

LOAD

= 50µA 0.75 0.9 V

LOAD

Off State Current at G1/G2 VPP1 = 10V, VG1 = 12V or VPP2 = 10V, 0.1 1 µA

VG2 = 12V or V

ON/OFF

= 0V

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

W

U

TYPICAL PERFORMANCE CHARACTERISTICS

Oscillator Frequency Switch Current Limit Switch Saturation Voltage

800

700

600

500

400

OSCILLATOR FREQUENCY (kHz)

300

–50

02550

–25

TEMPERATURE (°C)

75 100

LT1106 • TPC01

1000

900

800

700

600

SWITCH CURRENT (mA)

500

400

–50

VCC = 5V

02550

–25

TEMPERATURE (°C)

VCC = 3V

75 100

LT1106 • TPC02

250

ISW = 500mA

225

200

175

150

125

SWITCH SATURATION VOLTAGE (mV)

100

–50

02550

–25

TEMPERATURE (°C)

75 100

LT1106 • TPC03

3

LT1106

TEMPERATURE (°C)

–50

4.80

AVPP SENSE VOLTAGE (V)

4.85

4.90

4.95

5.00

5.10

–25

02550

LT1106 • TPC06

75 100

5.05

12/5 SELECT = 1

TEMPERATURE (°C)

–50

70

MAXIMUM DUTY CYCLE (%)

75

80

85

90

95

–25

02550

LT1106 • TPC09

75 100

W

U

TYPICAL PERFORMANCE CHARACTERISTICS

3/5 Comparator Threshold AVPP Sense Voltage AVPP Sense Voltage

4.00

3.95

3.90

12.20

12.15

12.10

12.05

12/5 SELECT = 0

3.85

3.80

THRESHOLD VOLTAGE (V)

3.75

3.70
–50

02550

–25

TEMPERATURE (°C)

Supply Current in Shutdown

14

12

10

8



6

4

SUPPLY CURRENT (µA)

2

0

–50

–25 0

VCC = 5V

VCC = 3V

TEMPERATURE (°C)

LT1106 • TPC04

50 100

25 75

LT1106 • TPC07

75 100

12.00

11.95

11.90

AVPP SENSE VOLTAGE (V)

11.85

11.80
–25 0 50

–50

TEMPERATURE (°C)

Supply Current

800

700

600

500

SUPPLY CURRENT (µA)

400

300

–50

02550

–25

TEMPERATURE (°C)

25

VCC = 5V
V

= 3V

CC

75

LT1106 • TPC05

75 100

LT1106 • TPC08

100

Maximum Duty Cycle

Start-Up Waveforms, I

12V

VAVPP
2V/DIV

VPP VALID

10V/DIV

ON/OFF

10V/DIV

4

50µs/DIV

LOAD

= 1mA

LT1106 • TPC10

V

OUT

5V/DIV

500mA/DIV

V

ON/OFF

10V/DIV

Start-Up Waveforms with Soft
Start, I

I

L

LOAD

= 10mA

50µs/DIV

LT1106 • TPC11

12V OUTPUT

1V/DIV

AC COUPLED

60mA

I

LOAD

10mA

Load Transient Response,
C

= 1µF

OUT

50µs/DIV

LT1106 • TPC12

UU U

PI FU CTIO S

LT1106

SELECT 12/5 (Pin 1): Tie to VIN or logic 1 for 5V output;
tie to GND or logic 0 for 12V output.

SOFT START (Pin 2): A 0.1µ F/1MΩ parallel RC from this
pin to GND provides a Soft Start function upon device
turn-on. Initially about 80µ A will flow from the pin into the
capacitor. When the voltage at the pin reaches approxi­mately 0.4V, current ceases flowing out of the pin. See
Applications Information section.

VCC (Pins 3, 4): Input Supply. Both pins should be tied
together. At least 1µF input bypass capacitance is re-
quired. More capacitance reduces ringing on the supply
line.

3/5 (Pin 5): Supply Comparator Output. This pin provides
logic output indicating the value of the input supply. High
when VCC = 5V; low when VCC = 3.3V.

PGND (Pins 6, 7): Power Ground. Connect to ground plane.
VSW (Pins 9, 10, 11): Collector of Power Switch. High dV/

dt present on this pin. To minimize radiated noise keep
layout short and direct.

GND (Pin 13): Signal Ground. Connect of ground plane.
VPP VALID (Pin 14): This pin provides a logic signal

indicating that ouput voltage is greater than 11.4V. Active
low with internal 200k pull-up resistor.

G1, G2 (Pins 16, 15): External MOSFET Gate Drives. When
VPP1 or VPP2 is greater than 11.7V, G1 or G2 is driven to
about 0.8V. When VPP1 or VPP2 is less than 11.7V, the
drives assume a high impedance state pulled up to the
AVPP pin through an internal 100k resistor.

VPP1, VPP2 (Pins 18, 17): Programming Power Inputs.
The LT1106 senses both VPP1 and VPP2 supplies at the
PCMCIA card socket. If VPP1 or VPP2 is greater than 11V,
the LT1106 operates in “Doze” Mode—the switching
regulator turns off and the drive to external P-channel
MOSFETs turns on. Supply current in Doze Mode is about
350µ A. Input current into VPP1 and VPP2 is about 1µA
when the device is shut down.

AVPP (Pin 19): Output Sense Pin. This pin connects to a
1MΩ resistive divider that sets the output voltage. In
shutdown, the resistor string is disconnected and current
into this pin is reduced to <1µA.

ON/OFF (Pin 20): Shutdown Control. When pulled below

1.5V, this pin disables the LT1106 and reduces supply
current to 10µA. All circuitry except the 3/5 comparator
is disabled in shutdown. The part is enabled when
ON/OFF is greater than 1.5V.

5

LT1106

BLOCK DIAGRA

12/5

SELECT

191

W

VPP2

VPP1AVPP

18

ON/0FF

17

20

G1

G2

16

15

565k

299k

4k

100k

BIAS

–

+

–

+

V

V

REF

+

C2

CC

200k

VPP VALID

14

36mV

+

–

+

C3

–

Q3

R2

700Ω

BIAS

V
3,4

CC

R1
3Ω

–

2

–

C1

+

V

CC

V

1.24V

REF

3.7V

+

–

OFF

500kHz

OSCILLATOR

5

3/5

SOFT START

13

GND

Q2
1×

SW

9,10,11

Q1
50×

6,7

PGND

LT1106 • BD

U

WUU

APPLICATIONS INFORMATION

Functional Description

The LT1106 is a micropower, step-up DC/DC converter
specifically configured for PCMCIA flash memory card
VPP generation. The device generates a 5V or 12V output
selectable via the 12/5 Select pin. If 12V is present on
either the VPP1 or VPP2 pins, gate drive outputs G1 and
G2 are driven low, turning on external PMOS devices. The
switching regulator inside the LT1106 is idled when 12V
is present on VPP1 or VPP2.

The VPP VALID output goes low when the voltage at AVPP
exceeds 11.4V This signal can be used to indicate pres­ence of a valid programming voltage. The 3/5 comparator
indicates whether the input voltage is 3.3V or 5V.

6

The Soft Start pin can be used to limit inrush current upon
start-up. A 0.1µ F capacitor in parallel with a 1M resistor is
connected between this pin and ground to limit peak
inductor current at start-up.

Switching Regulator Operation

When 12V is not present on the VPP1 or VPP2 pins and the
device is enabled (ON/OFF = 1), the LT1106 generates a
regulated voltage at the AVPP pin. This voltage is pro­grammable between 5V or 12V depending on the state of
the 12/5 Select pin. Referring to the block diagram, hyster­etic comparator C1 monitors AVPP via the resistor divider.
When the negative input of C2 falls below 1.24V, C1’s

LT1106

U

WUU

APPLICATIONS INFORMATION

output goes high, enabling the oscillator. Switch Q1
alternately turns on causing current build-up in the induc­tor; then turns off allowing the built-up current to flow into
the output capacitor via the catch diode. As the output
voltage increases, so does the voltage at C1’s negative
input. When it exceeds the reference voltage plus C1’s
hysteresis, C1 turns the oscillator off.

Switch current is limited to approximately 600mA by Q2,
R1 and C3. Two percent of Q1’s collector current flows in
Q2; this current flows through R1 causing a voltage drop
in R1 proportional to Q1’s collector current. When R1’s
drop equals 36mV, comparator C3 forces the oscillator
off. This action results in varying on-time, fixed off-time
operation that keeps peak switch current controlled. By
connecting a 0.1µF capacitor from the Soft Start pin to
ground, a current will flow in Q3 upon start-up. The current
flows through 700Ω resistor R2, reducing the amount of
current needed from Q2 to force the oscillator off. As
current flows into the 0.1µ F capacitor, the voltage at pin 2
increases and eventually current ceases to flow in Q3.

Inductor Selection

All components for use in PCMCIA Type I cards must be
less than 1.1mm high. This somewhat limits the selection
of appropriate inductors. Dale Electronics (605-665-9301)
manufactures the ILS-3825-01, a monolithic ferrite induc­tor that meets Type I height requirements. Generally,
inductors used with the LT1106 must fulfill several re­quirements. It must be able to carry 0.95A (the maximum
switch current) without saturation. DCR should be kept
low to maintain efficiency. The switching frequency of the
LT1106 is quite high, over 500kHz so magnetic material is
important. Ferrite core material works well in this fre­quency range. Avoid low cost iron powder cores which

have substantial AC loss at the LT1106’s switching fre­quency. Inductance value need not be over 10µH.

Capacitor Selection

The LT1106 will operate with 1µ F of output capacitance.
Output ripple voltage is approximately 400mV with this
value and can be reduced significantly by increasing
output capacitance. The ripple voltage, although on the
high side, poses no problems for programming flash
memory. If operating the device in 5V ouput mode the
capacitance should be increased. Ceramic capacitors are
suitable for the output. Distributed capacitance, i.e.,

0.1µF or 0.2µF units next to individual flash memory
chips, is acceptable. The input capacitor should have at
least some tantalum capacitance (low Q) to minimize
resonance on the input. Flash memory cards are typically
several inches away from a solid low impedance supply
due to sockets, connectors, etc. If just ceramic capaci­tors are used at the supply pin of the LT1106, switching
currents will resonate the supply line causing ringing that
can exceed 500mV
ceramic capacitors causes this. A few microfarad’s worth
of tantalum capacitors with moderate ESR and low Q
characteristics will reduce or eliminate the problem.

Diode Selection

As with inductors, most good power Schottky diodes are
in packages that exceed the 1.1mm height limit of the
Type I PCMCIA card. Motorola manufactures the MBRO530
Schottky diode, ideal for use with the LT1106. This
diode’s maximum height however, is 1.35mm, making it
difficult to use in Type 1 cards. Philips Components
manufactures the BAT54C. Four units in parallel make an
adequate diode.

. The high Q, low ESR nature of

P-P

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen­tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

7

LT1106

TYPICAL APPLICATION

Alternative Scheme Allows 12V from VPP1/VPP2 to Provide Power When LT1106 is in Shutdown



V

CC

3.3V/5V

+

U

4.7µF

D**

VPP1

D**

VPP2

L1*
10µH

V

CC

SW

LT1106

VPP VALID

AVPP

D**

12V/60mA

1µF

VPP VALID

470pF

POWER ON

ON/OFF

DALE ILS-3824-01

*

MBR0530 OR 4 BAT54s IN PARALLEL

**

U

PACKAGE DESCRIPTION

0.169 – 0.176*
(4.30 – 4.48)

0° – 8°

0.004 – 0.071
(0.09 – 0.18)

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).

0.020 – 0.028
(0.50 – 0.70)

Dimensions in inches (millimeters) unless otherwise noted.

0.0256
(0.65)

BSC

SOFT START

GND

SELPGND

1M 0.1µF

F Package

20-Lead Plastic TSSOP

0.007 – 0.012
(0.18 – 0.30)

LT1106 • TA03

0.043

(1.10)

MAX

0.002 – 0.006
(0.05 – 0.15)

0.252 – 0.260*
(6.40 – 6.60)

20 19 18 17 16 15



111214 13

0.246 – 0.256
(6.25 – 6.50)

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LT1109 5V to 12V/60mA VPP Generator 300µA IQ, 120kHz Oscillator
LT1109A 5V to 12V/120mA VPP Generator 300µA IQ, 120kHz Oscillator
LT1301 5V to 12V/200mA VPP Generator 120µA IQ, 155kHz Oscillator
LT1309 5V to 12V/60mA VPP Generator 650µA IQ, 650kHz Oscillator

Linear Technology Corporation

8

1630 McCarthy Blvd., Milpitas, CA 95035-7487

[phone]

●

FAX

: [phone]

●

TELEX

: 499-3977

7

6

F20 TSSOP 0395

8910

134

2

5

LT/GP 0595 10K • PRINTED IN THE USA

 LINEAR TECHNOLOGY CORPORATION 1995