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LT1106 Micropower Step-Up DC/DC Converter for PCMCIA Card Flash Memory
FEATURES
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DESCRIPTIO
60mA Output Current at 12V from 3V Supply Shutdown to 10A Programmable 12V or 5V Output Up to 85% Efficiency Quiescent Current: 750A Low VCESAT Switch: 300mV at 0.5A Typical Uses Low Value, Thin, Surface Mount Inductors Ultra-Thin 20-Lead TSSOP Package
APPLICATI
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PCMCIA Card Flash Memory VPP Generator Portable Computers Portable Instruments DC/DC Converter Module Replacements
The LT (R)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 1F of output capacitance. Quiescent current is 750A which drops to 350A when the card runs off the socket supply. The shutdown pin reduces supply current to only 10A. 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.
TYPICAL APPLICATI
12V, 60mA Flash Memory Programming Supply
VCC 3.3V/5V L1* 10H
86
D1**
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+
EFFICIENCY (%)
4.7F TANT ALUM 0.1F
0.1F VCC VPP1 G1 VPP2 G2 LT1106 VPP VALID 470pF 3/5 DETECT SOFT START 12/5 1M 0.1F 3/5 SW AVPP 1F VPP VALID 12V/60mA
VPP1
D BSS84 S D BSS84
VPP2 0.1F
S POWER ON *DALE ILS-3825-01 OR COILTRONICS CTX02-11238-3 **MOTOROLA MBR0530
ON/OFF PGND GND
LT1106 * TA01
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12V Output Efficiency
D1 = MBR0530 D1 = 4 BAT54Cs IN PARALLEL VIN = 5V 82 80 78 76 74 72 70 1 10 LOAD CURRENT (mA) 100
LT1106 * TA02
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VIN = 5V VIN = 3.3V VIN = 3.3V
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LT1106 ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW SELECT 12/5 SOFT START VCC VCC 3/5 PGND PGND NC VSW 1 2 3 4 5 6 7 8 9 20 ON/OFF 19 AVPP 18 VPP1 17 VPP2 16 G1 15 G2 14 VPP VALID 13 GND 12 NC 11 VSW
VCC Voltage ............................................................... 7V VSW Voltage ............................................................ 20V AVPP Voltage ......................................................... 20V VPP1, VPP2 Voltage ............................................... 20V G1, G2 Voltage ....................................................... 20V VON/OFF Voltage......................................................... 7V VSEL Voltage ............................................................. 7V ILIM Voltage .............................................................. 7V Maximum Power Dissipation ............................ 500mW Operating Temperature Range ..................... 0C to 70C Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C
ORDER PART NUMBER LT1106CF
VSW 10
F PACKAGE 20-LEAD PLASTIC TSSOP TJMAX = 100C, JA = 90C/W
Consult factory for Industrial and Military grade parts
ELECTRICAL CHARACTERISTICS
SYMBOL IQ PARAMETER Quiescent Current Quiescent Current, Shutdown "Doze" Mode Current Input Voltage Range Output Sense Voltage Output Referred Comparator Hysteresis fOSC DC tON VCESAT Oscillator Frequency Maximum Duty Cycle Switch On-Time Reference Line Regulation Switch Saturation Voltage Switch Leakage Current Switch Current Limit Soft Start Pin Current Select Input Voltage Low Select Input Voltage High ON/OFF Input Voltage Low ON/OFF Input Voltage High ON/OFF Bias Current
TA = 25C, VCC = 5V, VON/OFF = 3V, unless otherwise noted.
MIN TYP 750 9 320 2 6 5 12 15 35 400
q q q
CONDITIONS VSEL = 0.2V, AVPP = 12V VON/OFF = 0.2V VSEL = 0.2V, VPP1 or VPP2 = 12V VSEL = 3V, VPP1 and VPP2 Floating VSEL = 0.2V, VPP1 and VPP2 Floating VSEL = 3V VSEL = 0.2V Current Limit Not Asserted
MAX 900 15
UNITS A A A V V V mV mV
4.75 11.50
5.25 12.60
500 85 1.7 0.06 230 0.1
700 92 0.15 350 10 900 950 120 0.8
80
2V < VIN < 6V ISW = 0.5A VSW = 12V, Switch Off VIN = 5V, Soft Start Floating VIN = 3V, Soft Start Floating Soft Start Grounded 1.6 450 500
600 650 80
0.8 1.6 VON/OFF = 5V VON/OFF = 3V VON/OFF = 0V 16.0 8.0 0.1 24.0 14.0 1.1
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kHz % s %/V mV A mA mA A V V V V A A A
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LT1106
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER Select Pin Bias Current VPP1/VPP2 Input Sense Threshold AVPP Pin Input Current
TA = 25C, VCC = 5V, VON/OFF = 3V, unless otherwise noted.
MIN 11.0 TYP 0.1 11.5 50 0.1 50 0.1
q
CONDITIONS 0V < VSEL < 5V
MAX 1 11.9 90 1 90 1 12 0.3 4.2 0.9 1
UNITS A V A A A A V V V V V V A
VON/OFF = 0.2V VPP1/VPP2 Pin Input Current VON/OFF = 0.2V VPP VALID Threshold VPP VALID Output Voltage Low VPP VALID Output Voltage High 3/5 Comparator Threshold 3/5 Comparator Output High 3/5 Comparator Output Low Off State Current at G1/G2 ILOAD = 50A ILOAD = 50A VPP1 = 10V, VG1 = 12V or VPP2 = 10V, VG2 = 12V or VON/OFF = 0V AVPP Rising (High to Low Transition) ISINK = 100A ISOURCE = 2.5A
q
11.4 0.13 4 3.6 3.65 4.5 3.75 3.8 0.75 0.1
The q denotes specifications which apply over the full operating temperature range.
TYPICAL PERFORMANCE CHARACTERISTICS
Oscillator Frequency
800
OSCILLATOR FREQUENCY (kHz)
700
SWITCH CURRENT (mA)
900 800 VCC = 3V 700 VCC = 5V 600 500 400 -50
SWITCH SATURATION VOLTAGE (mV)
600
500
400
300 -50
-25
0 25 50 TEMPERATURE (C)
UW
75
LT1106 * TPC01
Switch Current Limit
1000 250
Switch Saturation Voltage
ISW = 500mA 225 200 175 150 125 100 -50
100
-25
0 25 50 TEMPERATURE (C)
75
100
-25
0 25 50 TEMPERATURE (C)
75
100
LT1106 * TPC02
LT1106 * TPC03
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LT1106 TYPICAL PERFORMANCE CHARACTERISTICS
3/ 5 Comparator Threshold
4.00 3.95
12.20 12/5 SELECT = 0 12.15
AVPP SENSE VOLTAGE (V)
12.10 12.05 12.00 11.95 11.90 11.85
3.90 3.85 3.80 3.75 3.70 -50
AVPP SENSE VOLTAGE (V)
THRESHOLD VOLTAGE (V)
-25
0 25 50 TEMPERATURE (C)
Supply Current in Shutdown
14 12
SUPPLY CURRENT (A)
10 8 6 4 2 0 -50
VCC = 5V
SUPPLY CURRENT (A)
VCC = 5V VCC = 3V
600
MAXIMUM DUTY CYCLE (%)
VCC = 3V
-25
50 25 0 TEMPERATURE (C)
Start-Up Waveforms, ILOAD = 1mA
12V VAVPP 2V/DIV VPP VALID 10V/DIV ON/OFF 10V/DIV 50s/DIV VOUT 5V/DIV
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UW
75
LT1106 * TPC04
AVPP Sense Voltage
5.10
AVPP Sense Voltage
12/5 SELECT = 1 5.05 5.00 4.95 4.90 4.85 4.80 -50
100
11.80 -50
-25
50 25 TEMPERATURE (C)
0
75
100
-25
0 25 50 TEMPERATURE (C)
75
100
LT1106 * TPC05
LT1106 * TPC06
Supply Current
800 95
Maximum Duty Cycle
700
90
85
500
80
400
75
75
100
300 -50
-25
0 25 50 TEMPERATURE (C)
75
100
70 -50
-25
0 25 50 TEMPERATURE (C)
75
100
LT1106 * TPC07
LT1106 * TPC08
LT1106 * TPC09
Start-Up Waveforms with Soft Start, ILOAD = 10mA
12V OUTPUT 1V/DIV AC COUPLED ILOAD 60mA 10mA
Load Transient Response, COUT = 1F
IL 500mA/DIV VON/OFF 10V/DIV
LT1106 * TPC10
50s/DIV
LT1106 * TPC11
50s/DIV
LT1106 * TPC12
LT1106
PI FU CTIO S
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 0.1F/1M parallel RC from this pin to GND provides a Soft Start function upon device turn-on. Initially about 80A 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 1F input bypass capacitance is required. 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 350A. Input current into VPP1 and VPP2 is about 1A when the device is shut down. AVPP (Pin 19): Output Sense Pin. This pin connects to a 1M resistive divider that sets the output voltage. In shutdown, the resistor string is disconnected and current into this pin is reduced to < 1A. ON/OFF (Pin 20): Shutdown Control. When pulled below 1.5V, this pin disables the LT1106 and reduces supply current to 10A. All circuitry except the 3/5 comparator is disabled in shutdown. The part is enabled when ON/OFF is greater than 1.5V.
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LT1106
BLOCK DIAGRA
12/5 SELECT 1 AVPP 19
565k
299k
VREF
+
C2
-
2 4k OFF C1 500kHz OSCILLATOR VCC VREF 1.24V 3.7V SOFT START SW 9,10,11 Q2 1x Q1 50x
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. The Soft Start pin can be used to limit inrush current upon start-up. A 0.1F 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
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100k
+
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-
-
-
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VPP1 18 VPP2 17 ON/0FF 20 G1 16 G2 15 BIAS VCC
+ +-
VCC 200k 14 VPP VALID C3
36mV
3,4
-
Q3
R2 700
R1 3
BIAS
+
5 3/5 13 GND 6,7 PGND
LT1106 * BD
-
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LT1106
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 0.1F capacitor from the Soft Start pin to ground, a current will flow in Q3 upon start-up. The current flows through 700 resistor R2, reducing the amount of current needed from Q2 to force the oscillator off. As current flows into the 0.1F 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 10H. Capacitor Selection The LT1106 will operate with 1F 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., 0.1F or 0.2F 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 500mVP-P. The high Q, low ESR nature of 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.
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.
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LT1106
TYPICAL APPLICATION
Alternative Scheme Allows 12V from VPP1/VPP2 to Provide Power When LT1106 is in Shutdown
D** VPP1 D** VPP2 VCC 3.3V/5V L1* 10H D**
+
4.7F VCC LT1106 VPP VALID 470pF SOFT START ON/OFF GND PGND SEL SW AVPP 1F VPP VALID 12V/60mA
POWER ON
PACKAGE DESCRIPTION
0.169 - 0.176* (4.30 - 4.48) 0 - 8
0.004 - 0.071 (0.09 - 0.18)
0.020 - 0.028 (0.50 - 0.70)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). 1 2 3 4 5 6 7 8 F20 TSSOP 0395 9 10
RELATED PARTS
PART NUMBER LT1109 LT1109A LT1301 LT1309 DESCRIPTION 5V to 12V/60mA VPP Generator 5V to 12V/120mA VPP Generator 5V to 12V/200mA VPP Generator 5V to 12V/60mA VPP Generator COMMENTS 300A IQ, 120kHz Oscillator 300A IQ, 120kHz Oscillator 120A IQ, 155kHz Oscillator 650A IQ, 650kHz Oscillator
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Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977
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1M
0.1F
*DALE ILS-3824-01 **MBR0530 OR 4 BAT54s IN PARALLEL
LT1106 * TA03
Dimensions in inches (millimeters) unless otherwise noted. F Package 20-Lead Plastic TSSOP
0.252 - 0.260* (6.40 - 6.60) 20 19 18 17 16 15 14 13 12 11
0.043 (1.10) MAX
0.0256 (0.65) BSC
0.007 - 0.012 (0.18 - 0.30)
0.002 - 0.006 (0.05 - 0.15)
0.246 - 0.256 (6.25 - 6.50)
LT/GP 0595 10K * PRINTED IN THE USA
(c) LINEAR TECHNOLOGY CORPORATION 1995

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