LINER LTC1470 Single and dual pcmcia protected 3.3v/5v vcc switch Datasheet

LTC1470/LTC1471
Single and Dual
PCMCIA Protected
3.3V/5V VCC Switches
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DESCRIPTION
FEATURES
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The LTC®1470 switches the VCC pins of a Personal Computer 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
Controlled Rise and Fall Times
The LTC1470 inputs are compatible with industry standard PCMCIA controllers. A built-in XOR ensures that both
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 section). The switch rise times are controlled to eliminate
power supply glitching.
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APPLICATIONS
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The LTC1470 features built-in SafeSlotTM current limit and
thermal shutdown. The output is limited to 1A during short
circuit to ground but 2A of peak operating current is
allowed.
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
5V
Linear Technology PCMCIA Product Family
3.3V
0.1µF
0.1µF
VCC
5VIN
3VIN
AOUT
(Hi-Z/3.3V/5V)
VCC
+
1µF
LTC1471
10k
AEN1
PCMCIA
CARD SLOT
CONTROLLER
VCC
AEN0
BEN1
PCMCIA
CARD SLOT
(Hi-Z/3.3V/5V)
BOUT
BEN0
GND
VCC
PCMCIA
CARD SLOT
+
1µF
10k
DEVICE
DESCRIPTION
PACKAGE
LT ®1312
Single PCMCIA VPP Driver/Regulator
8-Pin SO
LT1313
Dual PCMCIA VPP Driver/Regulator
16-Pin SO*
LTC1314
Single PCMCIA Switch Matrix
14-Pin SO
LTC1315
Dual PCMCIA Switch Matrix
24-Pin SSOP
LTC1470
Single Protected VCC 3.3V/5V Switch Matrix
8-Pin SO
LTC1471
Dual Protected VCC 3.3V/5V Switch Matrix
16-Pin SO*
LTC1472
Protected VCC and VPP Switch Matrix
16-Pin SO*
*Narrow Body
1470/71 TA01
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LTC1470/LTC1471
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ABSOLUTE MAXIMUM RATINGS
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
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
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PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
TOP VIEW
OUT 1
8
OUT
5VIN 2
7
3VIN
EN1 3
6
3VIN
EN0 4
5
LTC1470CS8
S8 PART MARKING
GND
S8 PACKAGE
8-LEAD PLASTIC SO
1470
ORDER PART
NUMBER
TOP VIEW
AOUT 1
16 AOUT
A5VIN 2
15 A3VIN
AEN1 3
14 A3VIN
AEN0 4
13 GND
GND 5
12 BEN0
B3VIN 6
11 BEN1
B3VIN 7
10 B5VIN
BOUT 8
9
TJMAX = 100°C, θJA = 150°C/W
LTC1471CS
BOUT
S PACKAGE
16-LEAD PLASTIC SO
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
MAX
UNITS
3VIN
3.3V Supply Voltage Range
2.70
3.60
V
5VIN
5V Supply Voltage Range
4.75
5.25
V
I3VIN
3.3V Supply Current
Program to Hi-Z (Note 3)
Program to 3.3V, No Load (Note 3)
Program to 5V, No Load (Note 3)
●
●
●
0.01
40
0.01
10
80
10
µA
µA
µA
I5VIN
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
RON
3.3V Switch ON Resistance
5V Switch ON Resistance
Program to 3.3V, IOUT = 500mA
Program to 5V, IOUT = 500mA
0.12
0.14
0.16
0.18
Ω
Ω
ILKG
Output Leakage Current OFF
Program to Hi-Z, 0V ≤ VOUT ≤ 5V (Note 3)
±10
µA
ILIM3V
3.3V Current Limit
Program to 3.3V, VOUT = 0V (Note 4)
ILIM5V
5V Current Limit
Program to 5V, VOUT = 0V (Note 4)
VENH
Enable Input High Voltage
●
VENL
Enable Input Low Voltage
●
0.8
V
IEN
Enable Input Current
●
±1
µA
2
CONDITIONS
0V ≤ VEN ≤ 5V
MIN
TYP
●
1
A
1
A
2.0
V
LTC1470/LTC1471
ELECTRICAL CHARACTERISTICS
3VIN = 3.3V, 5VIN = 5V (Note 2), TA = 25°C, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t0 to t3
Delay and Rise Time (Note 5)
Transition from 0V to 3.3V, ROUT = 100Ω, COUT = 1µF
0.2
0.32
1.0
ms
t3 to t5
Delay and Rise Time (Note 5)
Transition from 3.3V to 5V, ROUT = 100Ω, COUT = 1µF
0.2
0.52
1.0
ms
t0 to t5
Delay and Rise Time (Note 5)
Transition from 0V to 5V, ROUT = 100Ω, COUT = 1µF
0.2
0.38
1.0
ms
The ● denotes the specifications which apply over the full operating
temperature range.
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
A3VIN supply input pins (14, 15) must be connected together, the two
B3VIN supply pins (6, 7) must be connected together and the two GND
pins (5, 13) must be connected together.
Note 2: Power for the input logic and charge pump circuitry is derived
from the 5VIN supply pin(s) which must be continuously powered.
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.
Note 5: To 90% of final value.
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TYPICAL PERFORMANCE CHARACTERISTICS
3VIN Supply Current (OFF)
3VIN Supply Current (3.3V ON)
3
2
1
–1
80
60
40
20
4
3
1
2
3VIN SUPPLY VOLTAGE (V)
0
1470/71 G04
5VIN Supply Current (3.3V ON)
150
100
50
1470/71 G03
1
2
3
4
5
5VIN SUPPLY VOLTAGE (V)
3.3V Switch Resistance
TA = 25°C
PROGRAMMED
TO 5V, NO LOAD
250
200
150
100
0
6
0.30
50
6
0
1470/71 G01
3.3V SWITCH RESISTANCE (Ω)
5VIN SUPPLY CURRENT (µA)
200
2
3
4
5
5VIN SUPPLY VOLTAGE (V)
1
5VIN Supply Current (5V ON)
TA = 25°C
PROGRAMMED
TO 3.3V, NO LOAD
1
2
–1
4
300
0
3
1470/71 G05
300
250
TA = 25°C
PROGRAMMED TO OFF
4
0
0
3
1
2
3VIN SUPPLY VOLTAGE (V)
0
TA = 25°C
PROGRAMMED TO
3.3V, NO LOAD
100
5VIN SUPPLY CURRENT (µA)
TA = 25°C
PROGRAMMED TO OFF
4
0
5VIN SUPPLY CURRENT (µA)
5VIN Supply Current (OFF)
5
120
3VIN SUPPLY CURRENT (µA)
3VIN SUPPLY CURRENT (µA)
5
0
(LTC1470 or 1/2 LTC1471)
PROGRAMMED
TO 3.3V
0.25
0.20
0.15
0.10
0.05
0
0
1
5
2
3
4
5VIN SUPPLY VOLTAGE (V)
6
1470/71 G02
0
25
50
75
100
JUNCTION TEMPERATURE (°C)
125
1470/71 G07
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LTC1470/LTC1471
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TYPICAL PERFORMANCE CHARACTERISTICS
OUTPUT VOLTAGE (V) INRUSH CURRENT (A)
5V SWITCH RESISTANCE (Ω)
PROGRAMMED
TO 5V
0.20
0.15
0.10
0.05
0
0
25
50
75
100
JUNCTION TEMPERATURE (°C)
125
Inrush Current (5V Switch)
3
2
TJ = 25°C
COUT = 150µF
ROUT = 6.6Ω
1
0
COUT = 15µF
ROUT = 6.6Ω
6
4
COUT = 150µF
ROUT = 6.6Ω
2
0
– 0.2
0
0.2
0.4 0.6 0.8
TIME (ms)
1470/71 G06
1.0
1.2 1.4
OUTPUT VOLTAGE (V) INRUSH CURRENT (A)
Inrush Current (3.3V Switch)
5V Switch Resistance
0.30
0.25
(LTC1470 or 1/2 LTC1471)
3
2
TJ = 25°C
CURRENT
LIMITED
1
0
COUT = 150µF
ROUT = 10Ω
COUT = 15µF
ROUT = 10Ω
6
4
2
0
– 0.2
0
0.2
1470/71 G09
0.4 0.6 0.8
TIME (ms)
1.0
1.2 1.4
1470/71 G08
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PIN FUNCTIONS
LTC1470
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
supply input for the 5V NMOS switch. The second purpose
is to provide power for the input, gate drive, and protection
circuitry for both the 3.3V and 5V VCC switches. This pin
must therefore be continuously powered.
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
should not be forced below ground. Both inputs have
about 100mV of built-in hysteresis to ensure clean switching 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.
GND (Pin 5): Ground Connection.
3VIN (Pins 6, 7): 3V Input Supply Pins. The 3VIN supply
pins serve as the power supply input for the 3.3V switches.
These pins do not provide any power to the internal control
circuitry and therefore do not consume any power when
unloaded or turned off.
LTC1470/LTC1471
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PIN FUNCTIONS
LTC1471
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 continuously powered.
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
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BLOCK DIAGRAM
should not be forced below ground. All four inputs have
about 100mV of built-in hysteresis to ensure clean switching 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.
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.
(LTC1470 or 1/2 LTC1471)
5VIN
GATE CHARGE
AND
DISCHARGE
CONTROL LOGIC
EN0
EN1
TTL-TO-CMOS
CONVERTER
TTL-TO-CMOS
CONVERTER
BREAK-BEFOREMAKE SWITCH
AND CONTROL
OSCILLATOR
AND BIAS
CHARGE
PUMP
GATE CHARGE
AND
DISCHARGE
CONTROL LOGIC
0.14Ω
CURRENT LIMIT
AND THERMAL
SHUTDOWN
OUTPUT
0.12Ω
3VIN
LTC1470-BD01
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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 approximately 12V of gate drive for the internal low RDS(ON)
NMOS VCC switches from the 5VIN power supply. Therefore, 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 -low or active-high PCMCIA VCC switch control logic
(see Applications Information section for further details).
All switches are designed to ramp on slowly (400µs typical
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
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
Both switches are protected against accidental short circuits 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 shutdown which limits the power dissipation to safe levels.
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APPLICATIONS INFORMATION
The LTC1470/LTC1471 are designed to interface directly
with industry standard PCMCIA card controllers.
3.3V
0.1µF
3VIN
Interfacing with the CL-PD6710
5V
3VIN
5VIN
0.1µF
Figure 1 is a schematic diagram showing the LTC1470
interfaced with a standard PCMCIA slot controller. The
LTC1470 accepts logic control directly from the CL-PD6710.
The XOR input function allows the LTC1470 to interface
directly to the active-low VCC control outputs of the CLPD6710 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.
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CL-PD6710
LTC1470
VCC _3
EN0
OUT
VCC _5
EN1
OUT
GND
(OFF/3.3V/5V)
+
1µF
TANT
TO CARD
VCC PINS
10k
1470/71 F01
Figure 1. Direct Interface to CL-PD6710 PCMCIA Controller
LTC1470/LTC1471
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APPLICATIONS INFORMATION
Truth Table for CL-PD6710 Controller
A_VCC _3
A_VCC _5
EN0
EN1
OUT
0
0
Hi-Z
0
1
3.3V
1
0
5V
1
1
Hi-Z
Supply Bypassing
For best results bypass the supply input pins with 1µF
capacitors as close as possible to the LTC1470. Sometimes 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.
Interfacing with “365” Type Controllers
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 activehigh logic control of the VCC switches (see the following
Switch Truth Table). No “glue” logic is required to interface to this type of PCMCIA compatible controller.
3.3V
5V
3VIN
5VIN
0.1µF
“365” TYPE
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 Performance Characteristics section). The output pin should
have a 0.1µF to 1µF capacitor for noise reduction and
smoothing.
A 10k pull-down resistor is recommended at the output to
ensure that the output capacitor is fully discharged when the
output is switched OFF. This resistor also ensures that the
output is discharged between the 3.3V and 5V transition.
0.1µF
3VIN
Output Capacitors and Pull-Down Resistor
LTC1470
A_VCC _EN0
A_VCC _EN1
Supply Sequencing
OUT
EN0
OUT
EN1
GND
(OFF/3.3V/5V)
+
1µF
TANT
TO CARD
VCC PINS
10k
1470/71 F02
Figure 2. Direct Interface with “365” Type PCMCIA Controller
Truth Table for “365” Type Controller
A_VCC _EN0
A_VCC_EN1
EN0
EN1
OUT
0
0
Hi-Z
0
1
3.3V
1
0
5V
1
1
Hi-Z
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.
It is interesting to note, however, that the switches are NMOS
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.
If the 5V supply must be turned off, it is important to program
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.
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LTC1470/LTC1471
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APPLICATIONS INFORMATION
TOTAL SYSTEM COST CONSIDERATIONS
LTC1142HV Auxiliary Winding Power Supply
The cost of an additional step-up switching regulator, inductor, rectifier and capacitors to produce 12V for VPP can be
eliminated by using an auxiliary winding on either the 3.3V
or 5V output of the system switching regulator to produce an
auxiliary 15V supply for VPP power.
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.)
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.
VIN
6.5V TO 18V
VIN
PDRIVE
1/2 LTC1142HV
(5V REG)
NDRIVE
SENSE +
D1
MBRS140
+
9
C1
68µF
R4
22Ω
C4
1000pF
20
Q2
15
14
Q3
2N7002
D3
MBRS130T3
T1*
R1
30µH
100Ω
1.8:1
D2
MBRS140
+
AEN0
AVPPEN1
AEN1
AVPPOUT
TO “A” SLOT
VPP PINS
+
1µF
AVALID
LT1313
C5
22µF
R5
0.033Ω
R2
100Ω
AVPPEN0
AVALID
+
VS
VS
Q1
R3
18k
AVPPEN0
(15V)
10
C2
1000pF
SENSE –
A turns ratio of 1:1.8 is used for transformer T1 to ensure that
the input voltage to the LT1313 falls between 13V and 20V
under all load conditions. The 9V output from this additional
5V
OUTPUT
BVPPEN0
BEN0
ASENSE
BVPPEN1
BEN1
BVPPOUT
BVALID
FROM “A” VCC PINS
1µF
BVALID
C3
220µF
GND
TO “B” SLOT
VPP PINS
+
BSENSE
GND
FROM “B” VCC PINS
Q4
2N7002
BVPPEN0
3.3V
0.1µF
A3VIN A3VIN B3VIN B3VIN
* LPE-6562-A026 DALE (605) 665-9301
5V
0.1µF
A5VIN
BOUT
B5VIN
BOUT
+
LTC1471
AVCCEN0
AEN0
AVCCEN1
AEN1
BVCCEN0
BEN0
BVCCEN1
BEN1
1µF
TANT
TO “A” SLOT
VCC PINS
10k
AOUT
GND
GND
AOUT
+
1µF
TANT
10k
TO “B” SLOT
VCC PINS
1470/71 F03
Figure 3. Cost Effective Complete SafeSlot Dual PCMCIA Power Management System
(with 15V Auxiliary Supply from LTC1142HV 5V Regulator Inductor)
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LTC1470/LTC1471
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APPLICATIONS INFORMATION
winding is rectified by diode D2, added to the main 5V output
and applied to the input of the LT1313. (Note that the
auxiliary winding must be phased properly as shown in
Figure 3.)
When the 12V output is activated by a TTL high on either VPP
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.
Continuous mode operation is only invoked when the LT1313
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.
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.
Auxiliary Power from the LTC1142 3.3V Output
For low-battery count applications (< 6.5V) it is necessary to
modify the circuit of Figure 3. As the input voltage falls, the
5V duty cycle increases to the point where there is simply not
enough time to transfer energy from the 5V primary winding
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
and the VPP pins require 3.3V or 5V. In this circuit, however,
Q3 and Q4 force the LTC1142 3.3V regulator into continuous
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.)
Burst Mode is a trademark of Linear Technology Corporation.
VIN
5.4V TO 11V
VIN
PDRIVE
24
+
23
C1
68µF
D2
MBRS1100
Q1
15V AUX
SUPPLY
1/2 LTC1142
(3.3V REG)
NDRIVE
6
Q2
C2
1000pF
D4
18V
28
+
HC86
+
C5
68µF
R4
0.033Ω
R2
100Ω
R3
12k
AENVPP0
AENVPP1
3.37:1
100Ω
1
SENSE +
SENSE –
D3
MBRS130T3 T1*
15µH
R1
3.3V
OUTPUT
C3
220µF
Q3
2N7002
HC86
BENVPP0
BENVPP1
Q4
2N7002
*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
U
TYPICAL APPLICATIONS
Dual Slot 3.3V/5V PCMCIA Controller with SafeSlot Current Limit
(Systems with No 12V Power Requirements)
3.3V
0.1µF
A3VIN A3VIN B3VIN B3VIN
5V
0.1µF
A5VIN
BOUT
B5VIN
BOUT
CL-PD6710
VCC
(OFF/3.3V/5V)
+
LTC1471
A_VCC _3
AEN0
A_VCC _5
AEN1
B_VCC _3
BEN0
B_VCC _5
BEN1
1µF
TANT
VCC
PCMCIA
CARD SLOT
10k
VCC
AOUT
(OFF/3.3V/5V)
GND
GND
AOUT
+
1µF
TANT
VCC
PCMCIA
CARD SLOT
10k
1470/71 TA02
Single Slot PCMCIA Controller with SafeSlot Current Limit
Protection Using LT1312 Single VPP Regulator/Driver
VLOGIC
13V TO 20V*
51k
VCC
VPP_PGM
VS
EN0
VPPOUT
VPP2
PCMCIA
CARD SLOT
VCC
SENSE
VALID
VPP_VALID
1µF
LT1312
EN1
VPP_VCC
VPP1
+
GND
CIRRUS LOGIC
CL-PD6710
3.3V
0.1µF
3VIN
5VIN
5V
3VIN
10k
0.1µF
LTC1470
VCC _5
EN0
VCC _3
EN1
0UT
0UT
GND
* FROM OVERWINDING ON 3.3V OR 5V INDUCTOR IN SYSTEM POWER SUPPLY.
SEE FIGURES 3, 4 FOR FURTHER DETAIL
10
+
1µF
TANT
1470/71 TA03
LTC1470/LTC1471
U
TYPICAL APPLICATIONS
Dual Slot PCMCIA Controller with SafeSlot Current Limit
Protection Using LT1313 Dual VPP Regulator/Driver
VLOGIC
13V TO 20V*
0.1µF
51k
A_VPP_PGM
AEN0
A_VPP_VCC
VPP1
BVS
AVS
AVPPOUT
VPP2
PCMCIA
CARD SLOT
#1
+
1µF
AEN1
AVALID
VCC
ASENSE
VPP1
LT1313
B_VPP_PGM
BVPPOUT
BEN0
VPP2
PCMCIA
CARD SLOT
#2
+
1µF
B_VPP_VCC
BEN1
VPP_VALID
BVALID
VCC
BSENSE
GND
GND
CL-PD6720
3.3V
0.1µF
A3VIN A3VIN B3VIN B3VIN
5V
0.1µF
A5VIN
BOUT
B5VIN
BOUT
(OFF/3.3V/5V)
+
LTC1471
A_VCC _3V
AEN0
A_VCC _5V
AEN1
B_VCC _3V
BEN0
B_VCC _5V
BEN1
1µF
TANT
10k
AOUT
(OFF/3.3V/5V)
GND
GND
AOUT
+
1µF
TANT
10k
* FROM OVERWINDING ON 3.3V OR 5V INDUCTOR IN SYSTEM POWER SUPPLY.
SEE FIGURES 3, 4 FOR FURTHER DETAILS
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 circuits as described herein will not infringe on existing patent rights.
1470/71 TA04
11
LTC1470/LTC1471
U
PACKAGE DESCRIPTION
Dimensions in inches (millimeters) unless otherwise noted.
S8 Package
8-Lead Plastic SOIC
0.010 – 0.020
× 45°
(0.254 – 0.508)
6
5
0.004 – 0.010
(0.101 – 0.254)
0°– 8° TYP
0.016 – 0.050
0.406 – 1.270
7
8
0.053 – 0.069
(1.346 – 1.752)
0.008 – 0.010
(0.203 – 0.254)
0.189 – 0.197*
(4.801 – 5.004)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).
0.150 – 0.157*
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
1
3
2
4
SO8 0294
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)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
2
3
4
5
6
7
8
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0° – 8° TYP
0.016 – 0.050
0.406 – 1.270
0.014 – 0.019
(0.355 – 0.483)
0.050
(1.270)
TYP
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.
12
Linear Technology Corporation
LT/GP 0495 10K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977
 LINEAR TECHNOLOGY CORPORATION 1995