LT1470 [Linear]
Single and Dual PCMCIA Protected 3.3V/5V VCC Switches; 单，双PCMCIA保护3.3V / 5V VCC开关
| 型号： | LT1470 |
| 厂家： | 
Linear |
| 描述： | Single and Dual PCMCIA Protected 3.3V/5V VCC Switches |
| 文件： | 总12页 (文件大小：230K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1470/LTC1471
Single and Dual
PCMCIA Protected
3.3V/5V VCC Switches
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DESCRIPTION
FEATURES
The LTC®1470 switches the VCC pins of a Personal Com-
puter Memory Card International Association (PCMCIA)
card slot between three operating states: OFF, 3.3V and
5V. Two low RDS(ON) N-channel power MOSFETs are
driven by a built-in charge pump which generates a
voltage higher than the supply voltage to fully enhance
each switch when selected by the input control logic.
■
Single 3.3V/5V Switch in 8-Pin SO Package
■
Dual 3.3V/5V Switch in 16-Pin SO Package
■
Built-In Current Limit and Thermal Shutdown
■
Built-In Charge Pumps (No 12V Required)
■
Extremely Low RDS(ON) MOSFET Switches
■
Output Current Capability: 1A
Inrush Current Limited (Drives 150µF Loads)
Quiescent Current in Standby: 1µA
No Parasitic Body Diodes
Built-In XOR Function Eliminates “Glue” Logic
Break-Before-Make Switching
■
■
The LTC1470 inputs are compatible with industry stan-
dardPCMCIAcontrollers.Abuilt-inXORensuresthatboth
switches are never on at the same time. This function also
makes the LTC1470 compatible with both active-low and
active-high controllers (see Applications Information sec-
tion). The switch rise times are controlled to eliminate
power supply glitching.
The LTC1470 features built-in SafeSlotTM current limit and
thermalshutdown.Theoutputislimitedto1Aduringshort
circuit to ground but 2A of peak operating current is
allowed.
■
■
■
■
Controlled Rise and Fall Times
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APPLICATIONS
■
Notebook Computers
■
Palmtop Computers
■
Pen-Based Computers
■
Handi-Terminals
■
PC Card Reader/Writers
3.3V/5V Power Supply Switch
The LTC1471 is a dual version of the LTC1470 and is
available in a 16-pin SO package.
■
, LTC and LT are registered trademarks of Linear Technology Corporation.
SafeSlot is a trademark of Linear Technology Corporation.
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TYPICAL APPLICATION
Dual Slot PCMCIA 3.3V/5V VCC Switch
Linear Technology PCMCIA Product Family
5V
3.3V
0.1µF
DEVICE
LT®1312 Single PCMCIA VPP Driver/Regulator
LT1313 Dual PCMCIA VPP Driver/Regulator
DESCRIPTION
PACKAGE
8-Pin SO
0.1µF
V
V
CC
CC
5V
IN
3V
PCMCIA
IN
16-Pin SO*
14-Pin SO
24-Pin SSOP
8-Pin SO
(Hi-Z/3.3V/5V)
CARD SLOT
AOUT
LTC1314 Single PCMCIA Switch Matrix
LTC1315 Dual PCMCIA Switch Matrix
+
10k
10k
1µF
LTC1471
AEN1
V
V
LTC1470 Single Protected V 3.3V/5V Switch Matrix
CC
CC
CC
PCMCIA
CARD SLOT
CONTROLLER
AEN0
BEN1
BEN0
PCMCIA
CARD SLOT
LTC1471 Dual Protected V 3.3V/5V Switch Matrix
16-Pin SO*
16-Pin SO*
CC
(Hi-Z/3.3V/5V)
BOUT
GND
LTC1472 Protected V and VPP Switch Matrix
CC
+
1µF
*Narrow Body
1470/71 TA01
1
LTC1470/LTC1471
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ABSOLUTE MAXIMUM RATINGS
Operating Temperature ............................... 0°C to 70°C
Junction Temperature.......................................... 100°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
3.3V Supply Voltage (Note 1) .................................. 7V
5V Supply Voltage (Note1) ....................................... 7V
Enable Input Voltage........................ 7V to (GND – 0.3V)
Output Voltage (OFF) (Note 1) ......... 7V to (GND – 0.3V)
Output Short-Circuit Duration.......................... Indefinite
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PACKAGE/ORDER INFORMATION
TOP VIEW
ORDER PART
ORDER PART
NUMBER
NUMBER
AOUT
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
AOUT
TOP VIEW
A5V
IN
A3V
IN
OUT
1
2
3
4
8
7
6
5
OUT
LTC1470CS8
LTC1471CS
AEN1
AEN0
GND
A3V
IN
5V
IN
3V
IN
GND
BEN0
BEN1
B5V
EN1
EN0
3V
IN
S8 PART MARKING
1470
B3V
IN
GND
B3V
IN
IN
S8 PACKAGE
8-LEAD PLASTIC SO
BOUT
BOUT
S PACKAGE
16-LEAD PLASTIC SO
TJMAX = 100°C, θJA = 150°C/W
TJMAX = 100°C, θJA = 100°C/W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS 3VIN = 3.3V, 5VIN = 5V (Note 2), TA = 25°C, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
2.70
4.75
TYP
MAX
3.60
5.25
UNITS
3V
5V
3.3V Supply Voltage Range
5V Supply Voltage Range
3.3V Supply Current
V
V
IN
IN
I
Program to Hi-Z (Note 3)
●
●
●
0.01
40
10
80
10
µA
µA
µA
3VIN
Program to 3.3V, No Load (Note 3)
Program to 5V, No Load (Note 3)
0.01
I
5V Supply Current
Program to Hi-Z (Note 3)
Program to 3.3V (Note 3)
Program to 5V (Note 3)
●
●
●
0.01
100
140
10
160
200
µA
µA
µA
5VIN
R
3.3V Switch ON Resistance
5V Switch ON Resistance
Program to 3.3V, I
= 500mA
OUT
= 500mA
0.12
0.14
0.16
0.18
Ω
Ω
ON
Program to 5V, I
OUT
I
I
I
Output Leakage Current OFF
3.3V Current Limit
Program to Hi-Z, 0V ≤ V
≤ 5V (Note 3)
OUT
●
±10
µA
A
LKG
Program to 3.3V, V
= 0V (Note 4)
OUT
1
1
LIM3V
LIM5V
5V Current Limit
Program to 5V, V
= 0V (Note 4)
A
OUT
V
V
Enable Input High Voltage
Enable Input Low Voltage
Enable Input Current
●
●
●
2.0
V
ENH
ENL
0.8
V
I
0V ≤ V ≤ 5V
±1
µA
EN
EN
2
LTC1470/LTC1471
3VIN = 3.3V, 5VIN = 5V (Note 2), TA = 25°C, unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
CONDITIONS
MIN
0.2
0.2
0.2
TYP
0.32
0.52
0.38
MAX
1.0
UNITS
ms
t to t
Delay and Rise Time (Note 5)
Delay and Rise Time (Note 5)
Delay and Rise Time (Note 5)
Transition from 0V to 3.3V, R
Transition from 3.3V to 5V, R
= 100Ω, C
= 100Ω, C
= 1µF
= 1µF
0
3
5
5
OUT
OUT
t to t
1.0
ms
3
OUT
OUT
t to t
Transition from 0V to 5V, R
= 100Ω, C = 1µF
OUT
1.0
ms
0
OUT
The
● denotes the specifications which apply over the full operating
Note 2: Power for the input logic and charge pump circuitry is derived
temperature range.
from the 5V supply pin(s) which must be continuously powered.
IN
Note 1: For the LTC1470, the two output pins (1, 8) must be connected
together and the two 3.3V supply input pins (6 , 7) must be connected
together. For the LTC1471, the two AOUT pins (1, 16) must be connected
together, the two BOUT pins (8, 9) must be connected together, the two
Note 3: Measured current is per channel with the other channel
programmed off for the LTC1471.
Note 4: The output is protected with foldback current limit which reduces
the short-circuit (0V) currents below peak permissible current levels at
higher output voltages.
A3V supply input pins (14, 15) must be connected together, the two
IN
B3V supply pins (6, 7) must be connected together and the two GND
IN
Note 5: To 90% of final value.
pins (5, 13) must be connected together.
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TYPICAL PERFORMANCE CHARACTERISTICS (LTC1470 or 1/2 LTC1471)
3VIN Supply Current (OFF)
3VIN Supply Current (3.3V ON)
5VIN Supply Current (OFF)
5
4
5
4
120
100
80
60
40
20
0
T = 25°C
A
PROGRAMMED TO OFF
T
= 25°C
T
A
= 25°C
A
PROGRAMMED TO OFF
PROGRAMMED TO
3.3V, NO LOAD
3
3
2
2
1
1
0
0
–1
–1
3
3
0
1
2
4
0
1
2
4
0
2
3
4
5
6
1
3V SUPPLY VOLTAGE (V)
IN
3V SUPPLY VOLTAGE (V)
IN
5V SUPPLY VOLTAGE (V)
IN
1470/71 G04
1470/71 G05
1470/71 G01
5VIN Supply Current (3.3V ON)
5VIN Supply Current (5V ON)
3.3V Switch Resistance
0.30
0.25
300
250
200
150
100
50
300
250
200
150
100
50
T
= 25°C
T
A
= 25°C
A
PROGRAMMED
TO 3.3V
PROGRAMMED
TO 3.3V, NO LOAD
PROGRAMMED
TO 5V, NO LOAD
0.20
0.15
0.10
0.05
0
0
0
0
25
50
75
100
125
0
2
3
4
5
6
0
2
3
4
5
6
1
1
JUNCTION TEMPERATURE (°C)
5V SUPPLY VOLTAGE (V)
IN
5V SUPPLY VOLTAGE (V)
IN
1470/71 G07
1470/71 G03
1470/71 G02
3
LTC1470/LTC1471
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TYPICAL PERFORMANCE CHARACTERISTICS (LTC1470 or 1/2 LTC1471)
Inrush Current (3.3V Switch)
Inrush Current (5V Switch)
5V Switch Resistance
0.30
0.25
3
2
1
0
3
2
1
0
T
= 25°C
T
= 25°C
J
J
PROGRAMMED
TO 5V
CURRENT
LIMITED
C
R
= 150µF
= 6.6Ω
OUT
OUT
0.20
0.15
C
= 150µF
= 10Ω
C
R
= 15µF
= 10Ω
OUT
R
OUT
OUT
C
= 15µF
= 6.6Ω
OUT
OUT
OUT
R
6
4
2
6
4
2
0.10
0.05
0
C
= 150µF
= 6.6Ω
OUT
OUT
R
0
0
0
25
50
75
100
125
–0.2
0
0.6 0.8
1.4
–0.2
0
0.6 0.8
0.2 0.4
1.0 1.2
0.2 0.4
1.0 1.2
1.4
JUNCTION TEMPERATURE (°C)
TIME (ms)
TIME (ms)
1470/71 G06
1470/71 G09
1470/71 G08
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PIN FUNCTIONS
LTC1470
should not be forced below ground. Both inputs have
about100mVofbuilt-inhysteresistoensurecleanswitch-
ing between operating modes. The LTC1470 is designed
to operate without 12V power. The gates of the VCC NMOS
switches are powered by charge pumps from the 5VIN
supply pins (see Applications Information section for
more detail). The Enable inputs should be turned off (both
asserted high or both asserted low) at least 100µs before
the 5VIN power is removed to ensure that both VCC NMOS
switch gates are fully discharged and both switches are in
the high impedance mode.
OUT (Pins 1, 8): Output Pins. The outputs of the LTC1470
are switched between three operating states: OFF, 3.3V
and 5V. These pins are protected against accidental short
circuits to ground by SafeSlot current limit circuitry which
protects the socket, the card, and the system power
supplies against damage. A second level of protection is
provided by thermal shutdown circuitry which protects
both switches against over-temperature conditions.
5VIN (Pin 2): 5V Input Supply Pin. The 5VIN supply pin
serves two purposes. The first purpose is as the power
supplyinputforthe5VNMOSswitch. Thesecondpurpose
istoprovidepowerfortheinput, gatedrive, andprotection
circuitry for both the 3.3V and 5V VCC switches. This pin
must therefore be continuously powered.
GND (Pin 5): Ground Connection.
3VIN (Pins 6, 7): 3V Input Supply Pins. The 3VIN supply
pinsserveasthepowersupplyinputforthe3.3Vswitches.
Thesepinsdonotprovideanypowertotheinternalcontrol
circuitry and therefore do not consume any power when
unloaded or turned off.
EN1, EN0 (Pins 3, 4): Enable Inputs. The two VCC Enable
inputs are designed to interface directly with industry
standard PCMCIA controllers and are high impedance
CMOS gates with ESD protection diodes to ground, and
4
LTC1470/LTC1471
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PIN FUNCTIONS
LTC1471
should not be forced below ground. All four inputs have
about100mVofbuilt-inhysteresistoensurecleanswitch-
ing between operating modes. The LTC1471 is designed
to operate without 12V power. The gates of the VCC NMOS
switches are powered by charge pumps from the 5VIN
supply pins (see Applications Information section for
more detail). The enable inputs should be turned off at
least 100µs before the 5VIN power is removed to ensure
that all NMOS switch gates are fully discharged and are in
the high impedance mode.
AOUT, BOUT(Pins 1, 16, 8, 9): Output Pins. The outputs
of the LTC1471 are switched between three operating
states: OFF, 3.3V and 5V. These pins are protected against
accidental short circuits to ground by SafeSlot current
limit circuitry which protects the socket, the card, and the
system power supplies against damage. A second level of
protection is provided by thermal shutdown circuitry.
5VIN (Pins 2, 10): 5V Input Supply Pins. The 5VIN supply
pins serve two purposes. The first purpose is as the power
supply input for the 5V NMOS switches. The second
purpose is to provide power for the input, gate drive, and
protection circuitry. These pins must therefore be con-
tinuously powered.
GND (Pins 5, 13): Ground Connections.
3VIN (Pins 6, 7, 14, 15): 3V Input Supply Pins. The 3VIN
supply pins serve as the power supply input for the 3.3V
switches. These pins do not not provide any power to the
internal control circuitry, and therefore, do not consume
any power when unloaded or turned off.
EN1, EN0 (Pins 3, 4, 11, 12): Enable Inputs. The enable
inputs are designed to interface directly with industry
standard PCMCIA controllers and are high impedance
CMOS gates with ESD protection diodes to ground, and
W
(LTC1470 or 1/2 LTC1471)
BLOCK DIAGRAM
5V
IN
GATE CHARGE
AND
0.14Ω
DISCHARGE
CONTROL LOGIC
TTL-TO-CMOS
EN0
CURRENT LIMIT
AND THERMAL
SHUTDOWN
BREAK-BEFORE-
MAKE SWITCH
AND CONTROL
CONVERTER
CHARGE
PUMP
OSCILLATOR
AND BIAS
OUTPUT
TTL-TO-CMOS
CONVERTER
GATE CHARGE
AND
EN1
DISCHARGE
CONTROL LOGIC
0.12Ω
3V
IN
LTC1470-BD01
5
LTC1470/LTC1471
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OPERATION
The LTC1470 (or 1/2 of the LTC1471) consists of the
following functional blocks:
on slowly (400µs typical rise time) but turns them off
much more quickly (typically 10µs).
Input TTL/CMOS Converters
Bias, Oscillator and Gate Charge Pump
The enable inputs are designed to accommodate a wide
range of 3V and 5V logic families. The input threshold
voltage is approximately 1.4V with approximately 100mV
of hysteresis. The inputs enable the bias generator, the
gate charge pumps and the protection circuity which are
powered from the 5V supply. Therefore, when the inputs
are turned off, the entire circuit is powered down and the
5V supply current drops below 1µA.
When either the 3.3V or 5V switch is enabled, a bias
current generator and high frequency oscillator are turned
on. The on-chip capacitive charge pump generates ap-
proximately 12V of gate drive for the internal low RDS(ON)
NMOS VCC switches from the 5VIN power supply. There-
fore, an external 12V supply is not required to switch the
VCC output. The 5VIN supply current drops below 1µA
when both switches are turned off.
XOR Input Circuitry
Gate Charge and Discharge Control
By employing an XOR function, which locks out the 3.3V
switch when the 5V switch is turned on and locks out the
5V switch when the 3.3V switch is turned on, there is no
danger of both switches being on at the same time. This
XOR function also makes it possible to work with either
active-loworactive-highPCMCIAVCC switchcontrollogic
(see Applications Information section for further details).
Allswitchesaredesignedtoramponslowly(400µstypical
rise time). Turn-off time is much quicker (typically 10µs).
To ensure that both VCC NMOS switch gates are fully
discharged, program the switch to the high impedance
mode at least 100µs before turning off the 5V power
supply.
Switch Protection
Break-Before-Make Switch Control
Both switches are protected against accidental short cir-
cuits with SafeSlot foldback current limit circuits which
limit the output current to typically 1A when the output is
shorted to ground. Both switches also have thermal shut-
down which limits the power dissipation to safe levels.
Built-in delays are provided to ensure that the 3.3V and 5V
switches are non-overlapping. Further, the gate charge
pump includes circuitry which ramps the NMOS switches
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APPLICATIONS INFORMATION
3.3V
The LTC1470/LTC1471 are designed to interface directly
with industry standard PCMCIA card controllers.
0.1µF
3V
3V
IN
IN
5V
5V
IN
Interfacing with the CL-PD6710
0.1µF
Figure 1 is a schematic diagram showing the LTC1470
interfaced with a standard PCMCIA slot controller. The
LTC1470acceptslogiccontroldirectlyfromtheCL-PD6710.
LTC1470
CL-PD6710
V
V
_3
_5
EN0
EN1
OUT
OUT
CC
(OFF/3.3V/5V)
TO CARD
PINS
CC
V
CC
+
GND
1µF
TANT
The XOR input function allows the LTC1470 to interface
directly to the active-low VCC control outputs of the CL-
PD6710 for 3.3V/5V voltage selection (see the following
Switch Truth Table). Therefore, no “glue” logic is required
to interface to this PCMCIA compatible card controller.
10k
1470/71 F01
Figure 1. Direct Interface to CL-PD6710 PCMCIA Controller
6
LTC1470/LTC1471
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APPLICATIONS INFORMATION
Truth Table for CL-PD6710 Controller
Supply Bypassing
For best results bypass the supply input pins with 1µF
capacitors as close as possible to the LTC1470. Some-
times much larger capacitors are already available at the
outputs of the 3.3V and 5V power supply. In this case it is
still good practice to use 0.1µF capacitors as close as
possible to the device, especially if the power supply
output capacitors are more than 2" away on the printed
circuit board.
A_V _3
A_V _5
CC
CC
EN0
0
EN1
0
OUT
Hi-Z
3.3V
5V
0
1
1
0
1
1
Hi-Z
Interfacing with “365” Type Controllers
Output Capacitors and Pull-Down Resistor
The LTC1470 also interfaces directly with “365” type
controllers as shown in Figure 2. Note that the VCC Enable
inputs are connected differently than to the CL-PD6710
controller because the “365” type controllers use active-
high logic control of the VCC switches (see the following
Switch Truth Table). No “glue” logic is required to inter-
face to this type of PCMCIA compatible controller.
The output pin is designed to ramp on slowly, typically
400µs rise time. Therefore, capacitors as large as 150µF
can be driven without producing voltage spikes on the
3VIN or 5VIN supply pins (see graphs in Typical Perfor-
mance Characteristics section). The output pin should
have a 0.1µF to 1µF capacitor for noise reduction and
smoothing.
3.3V
0.1µF
A 10k pull-down resistor is recommended at the output to
ensurethattheoutputcapacitorisfullydischargedwhenthe
output is switched OFF. This resistor also ensures that the
output is discharged between the 3.3V and 5V transition.
3V
3V
IN
IN
5V
5V
IN
0.1µF
“365” TYPE
CONTROLLER
LTC1470
Supply Sequencing
A_V _EN0
CC
EN0
EN1
OUT
OUT
(OFF/3.3V/5V)
TO CARD
PINS
A_V _EN1
CC
Because the 5V supply is the source of power for both of the
switch control circuits, it is best to sequence the power
supplies such that the 5V supply is powered before, or
simultaneous to, the application of 3.3V.
V
CC
+
GND
1µF
TANT
10k
1470/71 F02
Figure 2. Direct Interface with “365” Type PCMCIA Controller
Truth Table for “365” Type Controller
Itisinterestingtonote,however,thattheswitchesareNMOS
transistors which require charge pumps to generate gate
voltages higher than the supply rails for full enhancement.
Because the gate voltages start at 0V when the supplies are
first activated, the switches always start in the off state and
do not produce glitches at the outputs when powered.
A_V _EN0 A_V _EN1
CC
CC
EN0
EN1
OUT
Hi-Z
3.3V
5V
0
0
1
1
0
1
0
1
Ifthe5Vsupplymustbeturnedoff,itisimportanttoprogram
all switches to the Hi-Z or 0V state at least 100µs before the
5V power is removed to ensure that the NMOS switch gates
are fully discharged to 0V. Whenever possible, however, it is
best to leave the 5VIN pin(s) continuously powered. The
LTC1470/LTC1471 quiescent current drops to <1µA with all
the switches turned off and therefore no 5V power is
consumed in the standby mode.
Hi-Z
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LTC1470/LTC1471
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APPLICATIONS INFORMATION
LTC1142HV Auxiliary Winding Power Supply
TOTAL SYSTEM COST CONSIDERATIONS
Figure 3 is a schematic diagram which describes how a
loosely regulated 15V power supply is created by adding an
auxiliary winding to the 5V inductor in a split 3.3V/5V
LTC1142HV power supply system. An LT1313, dual VPP
regulator/driver with SafeSlot protection, produces “clean”
3.3V, 5V and 12V power from this loosely regulated 15V
output for the PC card slot VPP pins. (See LT1312 and
LT1313 data sheets for further detail.)
Thecostofanadditionalstep-upswitchingregulator, induc-
tor, rectifier and capacitors to produce 12V for VPP can be
eliminated by using an auxiliary winding on either the 3.3V
or5Voutputofthesystemswitchingregulatortoproducean
auxiliary 15V supply for VPP power.
And, because the LTC1470/LTC1471 do not require 12V
power to operate (only 5V), the 12V VPP regulation and
switching may be operated separately from the 3.3V/5V VCC
switching. This increases system configuration flexibility
and reduces total system cost by eliminating the need for a
third regulator for 12V power.
Aturnsratioof1:1.8isusedfortransformerT1toensurethat
the input voltage to the LT1313 falls between 13V and 20V
under all load conditions. The 9V output from this additional
V
IN
D1
MBRS140
6.5V TO 18V
(15V)
10
9
V
IN
+
C4
1000pF
C1
R4
68µF
V
S
V
S
22Ω
TO “A” SLOT
VPP PINS
AVPPEN0
AVPPEN1
AVALID
AEN0
AEN1
AVPP
OUT
PDRIVE
NDRIVE
Q1
Q2
+
+
1µF
D3
MBRS130T3
D2
MBRS140
20
15
14
AVALID
1/2 LTC1142HV
(5V REG)
1.8:1
T1*
30µH
LT1313
+
R1
100Ω
C5
22µF
+
BVPPEN0
BVPPEN1
BVALID
BEN0
ASENSE
BVPP
FROM “A” V PINS
CC
SENSE
TO “B” SLOT
VPP PINS
C2
BEN1
OUT
R5
R2
100Ω
1000pF
0.033Ω
1µF
BVALID
5V
OUTPUT
–
SENSE
+
R3
18k
C3
BSENSE
GND GND
FROM “B” V PINS
CC
220µF
Q3
2N7002
Q4
2N7002
BVPPEN0
AVPPEN0
3.3V
5V
0.1µF
0.1µF
A3V A3V B3V B3V
IN
IN
IN
IN
A5V
B5V
BOUT
BOUT
IN
* LPE-6562-A026 DALE (605) 665-9301
TO “A” SLOT
CC
IN
V
PINS
+
+
1µF
10k
10k
TANT
LTC1471
AEN0
AEN1
BEN0
BEN1
AV EN0
CC
AV EN1
CC
BV EN0
CC
AOUT
AOUT
TO “B” SLOT
BV EN1
CC
V
CC
PINS
GND
GND
1µF
TANT
1470/71 F03
Figure 3. Cost Effective Complete SafeSlot Dual PCMCIA Power Management System
(with 15V Auxiliary Supply from LTC1142HV 5V Regulator Inductor)
8
LTC1470/LTC1471
U
W U U
APPLICATIONS INFORMATION
R4 and C4 absorb transient voltage spikes associated with
the leakage inductance inherent in T1’s secondary winding
and ensure that the auxiliary supply does not exceed 20V.
windingisrectifiedbydiodeD2,addedtothemain5Voutput
and applied to the input of the LT1313. (Note that the
auxiliary winding must be phased properly as shown in
Figure 3.)
Auxiliary Power from the LTC1142 3.3V Output
Whenthe12VoutputisactivatedbyaTTLhighoneitherVPP
enable lines, the 5V section of the LTC1142HV is forced into
continuous mode operation. A resistor divider composed of
R2, R3 and switch Q3 forces an offset which is subtracted
from the internal offset at the Sense– input (pin 14) of the
LTC1142HV. When this external offset cancels the built-in
25mV offset, Burst ModeTM operation is inhibited and the
LTC1142HV is forced into continuous mode operation. (See
LTC1142HV data sheet for further detail.) In this mode, the
15V auxiliary supply can be loaded without regard to the
loading on the 5V output of the LTC1142HV.
For low-battery count applications (<6.5V) it is necessary to
modify the circuit of Figure 3. As the input voltage falls, the
5Vdutycycleincreasestothepointwherethereissimplynot
enoughtimetotransferenergyfromthe5Vprimarywinding
to the auxiliary winding. For applications where 12V load
currents exist in conjunction with these low input voltages,
use the circuit shown in Figure 4. In this circuit, the auxiliary
15V supply is generated from an overwinding on the 3.3V
inductor of the LTC1142 regulator output.
In Figure 3, power is drawn directly from the batteries
through D1 when the regulator is in Burst Mode operation
andtheVPPpinsrequire3.3Vor5V. Inthiscircuit, however,
Q3andQ4forcetheLTC11423.3Vregulatorintocontinuous
mode operation whenever 3.3V, 5V or 12V is programmed
at the VPPOUT pins of the LT1313. (See the LT1312 and
LT1313 data sheets for further detail.)
ContinuousmodeoperationisonlyinvokedwhentheLT1313
is programmed to 12V. If the LT1313 is programmed to 0V,
3.3V or 5V, power is obtained directly from the main power
source (battery pack) through diode D1. Again, the LT1313
output can be loaded without regard to the loading of the
main 5V output.
Burst Mode is a trademark of Linear Technology Corporation.
V
IN
5.4V TO 11V
24
23
6
V
IN
+
C1
68µF
D2
PDRIVE
NDRIVE
Q1
Q2
MBRS1100
15V AUX
SUPPLY
1/2 LTC1142
(3.3V REG)
D3
MBRS130T3
T1*
15µH
3.37:1
+
R1
D4
18V
C5
68µF
100Ω
1
+
SENSE
C2
1000pF
R4
0.033Ω
R2
100Ω
28
3.3V
OUTPUT
–
SENSE
+
R3
C3
220µF
12k
HC86
HC86
AENVPP0
AENVPP1
Q3
2N7002
Q4
2N7002
BENVPP0
BENVPP1
*CTX02-12753
COILTRONICS (407) 241-7876
1470/71 F04
Figure 4. Deriving 15V from the 3.3V Output of the LTC1142 for VPP Power
9
LTC1470/LTC1471
TYPICAL APPLICATIONS
U
Dual Slot 3.3V/5V PCMCIA Controller with SafeSlot Current Limit
(Systems with No 12V Power Requirements)
3.3V
5V
0.1µF
A3V A3V B3V B3V
V
V
IN
IN
IN
IN
CC
A5V
B5V
PCMCIA
CARD SLOT
BOUT
IN
(OFF/3.3V/5V)
CC
0.1µF
BOUT
IN
+
+
1µF
TANT
10k
CL-PD6710
A_V _3
LTC1471
AEN0
AEN1
BEN0
BEN1
CC
A_V _5
CC
V
V
CC
B_V _3
CC
AOUT
AOUT
PCMCIA
CARD SLOT
(OFF/3.3V/5V)
CC
B_V _5
CC
GND
GND
1µF
TANT
10k
1470/71 TA02
Single Slot PCMCIA Controller with SafeSlot Current Limit
Protection Using LT1312 Single VPP Regulator/Driver
V
LOGIC
13V TO 20V*
51k
V
V
CC
S
VPP1
VPP_PGM
EN0
EN1 LT1312
VALID SENSE
VPP
OUT
+
VPP2
PCMCIA
CARD SLOT
1µF
VPP_V
CC
V
CC
VPP_VALID
GND
3.3V
5V
CIRRUS LOGIC
CL-PD6710
0.1µF
0.1µF
3V
3V
IN
IN
5V
IN
10k
LTC1470
GND
V
_5
_3
EN0
EN1
0UT
0UT
CC
V
CC
+
1µF
TANT
* FROM OVERWINDING ON 3.3V OR 5V INDUCTOR IN SYSTEM POWER SUPPLY.
SEE FIGURES 3, 4 FOR FURTHER DETAIL
1470/71 TA03
10
LTC1470/LTC1471
U
TYPICAL APPLICATIONS
Dual Slot PCMCIA Controller with SafeSlot Current Limit
Protection Using LT1313 Dual VPP Regulator/Driver
V
LOGIC
13V TO 20V*
0.1µF
VPP1
AV
BV
S
S
51k
VPP2
A_VPP_PGM
A_VPP_V
AEN0
AEN1
AVPP
OUT
PCMCIA
CARD SLOT
#1
+
+
1µF
1µF
CC
V
CC
AVALID
ASENSE
VPP1
VPP2
LT1313
B_VPP_PGM
BEN0
BEN1
BVPP
OUT
PCMCIA
CARD SLOT
#2
B_VPP_V
CC
V
CC
VPP_VALID
BVALID
BSENSE
GND
GND
CL-PD6720
3.3V
5V
0.1µF
A3V A3V B3V B3V
IN
IN
IN
IN
A5V
B5V
BOUT
IN
(OFF/3.3V/5V)
0.1µF
BOUT
IN
+
+
1µF
10k
TANT
LTC1471
AEN0
AEN1
BEN0
BEN1
A_V _3V
CC
A_V _5V
CC
B_V _3V
AOUT
AOUT
CC
(OFF/3.3V/5V)
B_V _5V
CC
GND
GND
1µF
TANT
10k
* FROM OVERWINDING ON 3.3V OR 5V INDUCTOR IN SYSTEM POWER SUPPLY.
SEE FIGURES 3, 4 FOR FURTHER DETAILS
1470/71 TA04
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 represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
11
LTC1470/LTC1471
U
PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted.
S8 Package
8-Lead Plastic SOIC
0.189 – 0.197*
(4.801 – 5.004)
0.010 – 0.020
(0.254 – 0.508)
7
5
8
6
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.150 – 0.157*
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
0.016 – 0.050
0.406 – 1.270
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).
SO8 0294
1
3
4
2
S Package
16-Lead Plastic SOIC
0.386 – 0.394*
(9.804 – 10.008)
16
15
14
13
12
11
10
9
0.150 – 0.157*
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
5
7
8
1
2
3
4
6
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0° – 8° TYP
0.050
(1.270)
TYP
0.014 – 0.019
(0.355 – 0.483)
0.016 – 0.050
0.406 – 1.270
SO16 0893
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).
RELATED PARTS
See PCMCIA Product Family table on the first page of this data.
LT/GP 0495 10K • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
12
●
●
LINEAR TECHNOLOGY CORPORATION 1995
(408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977
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