MIC2560 Micrel Semiconductor, MIC2560 Datasheet - Page 7

• Manufacturer Part Number: MIC2560
• Description: PCMCIA Card Socket VCC and VPP Switching Matrix
• Manufacturer: Micrel Semiconductor

Figure 4. MIC2560 Typical PCMCIA memory card application with dual V
driven together.
However, many cost sensitive designs (especially notebook/
palmtop computers) connect V
is not required. This circuit is shown in Figure 4.
When a memory card is initially inserted, it should receive
V
determined by a combination of mechanical socket “keys”
and voltage sense pins. The card sends a handshaking data
stream to the controller, which then determines whether or
not this card requires V
V
level, the controller commands this change by disabling V
waiting at least 100ms, and then re-enabling the other V
voltage.
If no card is inserted or the system is in sleep mode, the
controller outputs a (V
which shuts down V
impedance output shutdown (sleep) mode, where current
consumption drops to nearly zero, with only tiny CMOS
leakage currents flowing.
During Flash memory programming with standard (+12V)
Flash memories, the PCMCIA controller outputs a (1,0) to the
EN0, EN1 control pins of the MIC2560, which connects
V
switches allow using small bypass capacitors (in some cases,
none at all) on the V
filtering action performed by a large filter capacitor on the
input supply voltage to V
filter capacitor is sufficient). The V
to 12.0V typically takes 250 s. After programming is com-
pleted, the controller outputs a (EN1, EN0) = (0,1) to the
MIC2560, which then reduces V
read verification. Break-before-make switching action re-
duces switching transients and lowers maximum current
spikes through the switch from the output capacitor. The flag
comparator prevents having high voltage on the V
capacitor from contaminating the V
low voltage V
November 1999
MIC2560
CC
CC
PP
. If the card is compatible with and desires a different V
IN to V
— either 3.3V
PP OUT
PP
switches until V
. The low ON resistance of the MIC2560
CC
CC OUT
0.3V or 5.0V 5%. The initial voltage is
CC3
. This also places the switch into a high
PP
PP
IN, V
and if the card is designed for dual
IN (usually the main power supply
and V
CC5
PP1
PP OUT
Controller
Card Slot
PP OUT
System
Supply
PCMCIA
Power
PP OUT
PP OUT
IN) = (0,0) to the MIC2560,
CC
to V
inputs, by disabling the
PP2
drops below the V
3.3V
to the V
12V
transition from V
pins, with the main
5V
and the MIC2557
CC
level for
PP OUT
CC
CC
CC
CC
CC
,
EN0
EN1
V CC5_EN
V CC3_EN
7
V PP IN
level selected. The lockout delay time varies with the load
current and the capacitor on V
and nominal I
Internal drive and bias voltage is derived from V
device control logic is powered from V
threshold voltages are compatible with common PCMCIA
controllers using either 3.3V or 5V supplies. No pull-up
resistors are required at the control inputs of the MIC2560.
Output Current and Protection
MIC2560 output switches are capable of more current than
needed in PC Card applications (1A) and meet or exceed all
PCMCIA specifications. For system and card protection,
output currents are internally limited. For full system protec-
tion, long term (millisecond or longer) output short circuits
invoke overtemperature shutdown, protecting the MIC2560,
the system power supplies, the card socket pins, and the
memory card. Overtemperature shutdown typically occurs at
a die temperature of 115 C.
Single V
For PC Card slots requiring only a single V
V
(i.e., Pins 1, 3, and 15 are all connected to system V
Either the V
enable the card slot V
preferred because of its lower ON resistance.
Suspend Mode
An additional feature in the MIC2560 is a pseudo power-down
mode, Suspend Mode, which allows operation without a V
IN supply. In Suspend Mode, the MIC2560 supplies 3.3V to
V
PCMCIA controller. This mode allows the system designer
the ability to turn OFF the V
when it is not specifically required. The PCMCIA card re-
ceives V
switch resistance rises to approximately 4.5 .
MIC2560
CC3 IN
CC
V CC3 IN
OUT whenever a V
V CC5 IN
and V
CC
at reduced capacity during Suspend Mode, as the
CC
CC5
PP OUT
CC
CC5 IN
Operation
(5.0V or 3.3V). Note that V
switch or the V
V PP1
V PP2
V CC
, the delay is approximately 250 s.
together and to the system V
Card Slot
PCMCIA
CC
CC
PP
; generally the V
output of 3.3V is enabled by the
supply generator to save power
PP OUT
CC3
. With a 0.1 F capacitor
switch may be used to
CC3
PP1
IN. Input logic
CC3
PP
and V
CC
IN. Internal
CC
, connect
switch is
MIC2560
PP2
supply
Micrel
CC
are
PP
).