Datasheet MIC2557BM Datasheet (MICREL)

Page 1

MIC2557 Micrel

MIC2557

PCMCIA Card Socket VPP Switching Matrix

General Description

The MIC2557 switches the four voltages required by PCMCIA (Personal Computer Memory Card International Association) card VPP Pins. The MIC2557 provides selectable 0V, 3.3V,

5.0V, or 12.0V (±5%) from the system power supply to V or V

. Output voltage is selected by two digital inputs.

PP2

PP1

Output current ranges up to 120mA. Four control states, VPP, VCC, high impedance, and active logic low are available. An auxiliary control input determines whether the high impedance (open) state or low logic state is asserted.

In either quiescent mode or full operation, the device draws very little current, typically less than 1µA.

The MIC2557 is available in an 8-pin SOIC and an 8-pin plastic DIP.

Applications

• PCMCIA VPP Pin Voltage Switch

• Power Supply Management

• Power Analog Switch

Features

• Complete PCMCIA VPP Switch Matrix in a Single IC

• No External Components Required

• Digital Selection of 0V, VCC, VPP, or High Imped– ance Output

• No V

PP OUT

Overshoot or Switching Transients

• Break-Before-Make Switching

• Low Power Consumption

• 120mA VPP (12V) Output Current

• Optional Active Source Clamp for Zero Volt Condition

• 3.3V or 5V Supply Operation

• 8-Pin SOIC Package

Ordering Information

Part Number Temperature Range Package

MIC2557BM –40°C to +85°C 8-pin SOIC MIC2557BM T&R –40°C to +85°C 8-SOIC Tape & Reel* * 2,500 Parts per reel.

Typical Application

+3.3V or +5V

PP(n) OUT

0.1µF

EN1 EN0 Hi-Z/Low V

0 0 0 0V, (Sink current) 0 0 1 Hi-Z (No Connect) 01 x VCC (3.3V or 5.0V) 10 x V 1 1 x Hi-Z (No Connect)

1µF 1µF

PP IN

+12V +5V

MIC2557

PP OUT

Pin Configuration

0.1µF

Hi-Z/ Low Control EN0 EN1

OUT

GND EN1

MIC2557

3 4

8 7 6 5

DD Hi-Z/Low EN0

Simplified Block Diagram

EN0 EN1

Hi-Z/Low

Decoder,

Driver &

Bias Control

PP IN

High

Impedance or

Pull Down

Select

PP OUT

For a dual PCMCIA Card Socket VPP Switching Matrix, see the MIC2558.

For a VPP and VCC Switching Matrix, see the MIC2560.

2-4 1997

Page 2

MIC2557 Micrel

Absolute Maximum Ratings (Notes 1 and 2)

Power Dissipation, T

SOIC 800 mW

Derating Factors (To Ambient)

SOIC 4 mW/°C Storage Temperature –65°C to +150°C Operating Temperature (Die) 125°C Operating Temperature (Ambient) –40°C to +85°C Lead Temperature (5 sec) 260°C Supply Voltage, V

Logic Input Voltages –0.3V to V Output Current

PP OUT

= 12V 600mA = V

AMBIENT

PP IN

≤ 25°C

15V

7.5V

250mA

Logic Block Diagram

EN1

EN0

PP IN

PP OUT

HiZ/ LOW

1997 2-5

GND

Page 3

MIC2557 Micrel

Electrical Characteristics: (Over operating temperature range with V

= VCC= 5V, V

= 12 V unless otherwise specified.)

PP IN

Symbol Parameter Conditions Min Typ Max Units

INPUT

VIN (Max) Input Voltage Range –5 V I

Logic 1 Input Voltage VDD = 3.3V or 5.0V 2.2 V Logic 0 Input Voltage VDD = 3.3V or 5.0V 0.8 V

Input Current 0 V < VIN < V

±1 µA

OUTPUT

, Hi-Z High Impedance Output EN0 = EN1 = 0, HiZ = 1 1 10 µA

OUT

Clamp Low Output Voltage EN0 = EN1 = HiZ = 0, I

Leakage Current 0 ≤ V

PP OUT

≤ 12V

Clamp Low Output Resistance Resistance to Ground. I

= 1.6mA 0.4 V

SINK

= 2mA 130 250 Ω

SINK

EN0 = EN1 =0,HiZ=0

Switch Resistance, I

= V

PP OUT

= –10 mA (Sourcing) 2.5 5 Ω

PP OUT

Switch Resistance, I

= V

PP OUT

PP IN

SWITCHING TIME (See Figure 1) t

Delay + Rise Time V

Delay + Fall Time V

Output Turn-On Delay V

Output Turn-Off Delay V

POWER SUPPLY

VDD Supply Current – 1 µA

VCC Supply Current I

= –100 mA (Sourcing) 0.5 1 Ω

PP OUT

= 0V to 5V (Notes 3, 5) 15 50 µs

PP OUT

= 5V to 12V (Notes 3, 5) 12 50 µs

PP OUT

= 12V to 5V (Notes 3, 5) 25 75 µs

PP OUT

= 5V to 0V (Notes 3, 5) 45 100 µs

PP OUT

= Hi-Z to 5V (Notes 4, 5) 10 50 µs

PP OUT

= 5V to Hi-Z (Notes 4, 5) 75 200 ns

PP OUT

= 0 – 1 µA

PP OUT

IPP Supply Current V

= 0 V – 10 µA

PP OUT

or V

. I

PPOUT

= 0.

10 40 µA

PP OUT

= V

2-6 1997

Page 4

MIC2557 Micrel

Electrical Characteristics, (continued)

Symbol Parameter Conditions Min Typ Max Units

POWER SUPPLY, continued

Operating Input Voltage 6V

VDDOperating Input Voltage 2.8 6 V

PP IN

Operating Input Voltage 8.0 14.5 V

NOTE 1: Functional operation above the absolute maximum stress ratings is not implied. NOTE 2: Static-sensitive device. Store only in conductive containers. Handling personnel and equipment should be grounded to

prevent damage from static discharge.

NOTE 3: With RL = 2.9kΩ and C

= 0.1µF on V

OUT

PP OUT

NOTE 4: RL = 2.9kΩ. RL is connected to VCC during t5 , and is connected to ground during t6. NOTE 5: Rise and fall times are measured to 90% of the difference between initial and final values.

Hi-Z/Low

EN0

EN1

PP OUT

12V

5VV

Figure 1. Timing Diagram

1997 2-7

Page 5

MIC2557 Micrel

Applications Information

12V

EN0

EN1

EN0

EN1

VCC Switch

PP INVCC

MIC2557

PP INVCC

MIC2557

PP1

PCMCIA

Card Slot

PP2

PCMCIA VPP control is easily accomplished using the MIC2557 voltage selector/switch IC. Two control bits determine output voltage and standby/operate mode condition. Output voltages of 0V (defined as less than 0.4V), V

(3.3V or 5V), VPP, or a high impedance state, are available. When either the high impedance or low voltage conditions are selected, the device switches into "sleep" mode, and draws only nanoamperes of leakage current.

The MIC2557 is a low-resistance power MOSFET switching matrix that operates from the computer system main power supply. Device power is obtained from VDD, which may be either 3.3V or 5V, and FET drive is obtained from V

PP IN

(usually +12V). Internal break-before-make switches determine the output voltage and device mode.

System

Power

Supply

Supply Bypassing

For best results, bypass V 1µF capacitors. V

PP OUT

and V

at their inputs with

PP IN

should have a 0.01µF to 0.1µF capacitor for noise reduction and electrostatic discharge (ESD) damage prevention. Larger values of output capacitor will create large current spikes during transitions, requiring larger bypass capacitors on the VCC and V

System

Power

Supply

PCMCIA

Card Slot

Controller

3.3V

12V

Select and

Switch

EN0

PP IN

Switch

MIC2557

PP IN

MIC2557

PP IN

MIC2557

PP IN

MIC2557

EN1

EN0

EN1

VCC Select and

EN0

EN1

EN0 EN1

PP IN

pins.

PP1

PP2

PP1

PP2

PCMCIA

Card Slot

PCMCIA

Card Slot

PCMCIA

Card Slot

Controller

EN0

EN1

EN0 EN1

PP INVCC

MIC2557

PP INVCC

MIC2557

PP1

PCMCIA

Card Slot

PP2

Figure 3. MIC2557 Typical two slot PCMCIA applica-

tion with single 5.0V VCC.

PCMCIA Implementation

The Personal Computer Memory Card International Association (PCMCIA) specification requires two VPP supply pins per PCMCIA slot. VPP is primarily used for programming Flash (EEPROM) memory cards. The two VPP supply pins may be programmed to different voltages. Fully implementing PCMCIA specifications requires two MIC2557, and a controller. Figure 2 shows this full configuration, supporting both 5.0V and 3.3V VCC operation. Figure 3 is a simplified design with fixed VCC = 5V. Palmtop computers, where size and battery life are tantamount, can sometimes use a compromise implementation, with V

PP1

tied to V

(see Figure

PP2

4). When a memory card is initially inserted, it should receive

VCC, usually 5.0V ±5%. The card sends a handshaking data stream to the controller, which then determines whether or not this card requires VPP and if the card is designed for 5.0V or 3.3V VCC. If the card uses 3.3V VCC, the controller commands this change, which is reflected on the VCC pins of both the PCMCIA slot and the MIC2557.

Figure 2. MIC2557 Typical two slot PCMCIA applica-

tion with dual VCC (5.0V or 3.3V).

During Flash memory programming, the PCMCIA controller outputs a (1,0) to the MIC2557, which connects V

PP IN

2-8 1997

Page 6

MIC2557 Micrel

System

Power

Supply

PCMCIA

Card Slot

Controller

3.3V

3.3V to 12V DC–DC

Converter

EN0

EN1

PP INVCCVDD

MIC2557

Switch

PP1

PCMCIA

Card Slot

PP2

Figure 4. MIC2557 Palmtop application. Note that the V

PP1

and V

pins are combined. Although this does

PP2

not fully satisfy PCMCIA specifications, it simplifies the circuitry and is acceptable in certain applications.

PP OUT

requires only a small bypass capacitor on V

. The low ON resistance of the MIC2557 switch

PP OUT

, with the main filtering action performed by a large filter capacitor on V

PP IN

. The V

PP OUT

transition from VCC to 12.0V typically takes 25µS. After programming is completed, the controller outputs a (0,1) to the MIC2557, which then reduces V

PP OUT

to the VCC level. Break-before-make switching action reduces switching transients and lowers maximum current spikes through the switch from the output capacitor.

If no card is inserted, or the system is in sleep mode, the controller outputs either a (0,0) or a (1,1) to the MIC2557. Either input places the switch into its shutdown mode, where only a small leakage current flows.

The HiZ/Low input controls the optional logic low output clamp. With HiZ/Low in the high state and ENO = EN1 = 0, V

PP OUT

Low in the low state and EN0 = EN1 = 0, V

enters a high impedance (open) state. With HiZ/

PP OUT

is clamped to ground, providing a logic low signal. The clamp does not require DC bias current for operation.

MOSFET drive and bias voltage is derived from V

PP IN

Internal device control logic is powered from VDD, which should be connected to the same supply voltage as the PCMCIA controller (normally either 3.3V or 5V).

Output Current

MIC2557 output switches are capable of far more current than usually needed in PCMCIA applications. PCMCIA V

output current is limited primarily by switch resistance voltage drop (I x R) and the requirement that V more than 5% below nominal. V short circuits to ground if V

PP OUT

and VCC are current limited

PP IN

PP OUT

cannot drop

will survive output

by the regulator that supplies these voltages.

1997 2-9