Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsInterface ICsInterface IC - I/O extensions EEPROM, POR I²C 400 kHz TSSOP 16

General Description

The DS4520 is a 9-bit nonvolatile (NV) I/O expander with

64 bytes of NV user memory controlled by an I

C-

compatible serial interface. The DS4520 offers users a

digitally programmable alternative to hardware jumpers

and mechanical switches that are being used to control

digital logic nodes. Furthermore, the digital state of each

pin can be read through the serial interface. Each I/O

pin is independently configurable. The outputs are open

drain with selectable pullups. Each output has the ability

to sink up to 12mA. Since the device is NV, it powers up

in the desired state allowing it to control digital logic

inputs immediately on power-up without having to wait

for the host CPU to initiate control.

Applications

RAM-Based FPGA Bank Switching for

Multiple Profiles

Selecting Between Boot Flash

Setting ASIC Configurations/Profiles

Servers

Network Storage

Routers

Telecom Equipment

PC Peripherals

Features

♦ Programmable Replacement for Mechanical

Jumpers and Switches

♦ Nine NV Input/Output Pins

♦ 64-Byte NV User Memory (EEPROM)

♦ I

C-Compatible Serial Interface

♦ Up to 8 Devices Can be Multidropped on the

Same I

C Bus

♦ Open-Drain Outputs with Configurable Pullups

♦ Outputs Capable of Sinking 12mA

♦ Low Power Consumption

♦ Wide Operating Voltage (2.7V to 5.5V)

♦ Operating Temperature Range: -40°C to +85°C

DS4520

9-Bit I

C Nonvolatile

I/O Expander Plus Memory

______________________________________________ Maxim Integrated Products 1

I/O_0

GND

I/O_8

I/O_7

I/O_6

I/O_5

SCL

SDA

TOP VIEW

I/O_1

I/O_2

I/O_3

I/O_4

DS4520

Pin Configuration

SCL

I/O_0

I/O_1

I/O_2

I/O_3

I/O_4

I/O_5

I/O_6

I/O_7

I/O_8

SDA

GND

FROM

SYSTEM

CONTROLLER

FPGA

CLOCK

GENERATOR

CPU

SPEED

SELECT

4.7kΩ

0.1μF

DS4520

Typical Operating Circuit

Rev 0; 6/04

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Add “/T&R” for tape and reel orders.

Ordering Information

PART TEMP RANGE PIN-PACKAGE

DS4520E -40°C to +85°C 16 TSSOP

Summary of content (10 pages)

PAGE 1
Rev 0; 6/04 9-Bit I2C Nonvolatile I/O Expander Plus Memory The DS4520 is a 9-bit nonvolatile (NV) I/O expander with 64 bytes of NV user memory controlled by an I 2 Ccompatible serial interface. The DS4520 offers users a digitally programmable alternative to hardware jumpers and mechanical switches that are being used to control digital logic nodes. Furthermore, the digital state of each pin can be read through the serial interface. Each I/O pin is independently configurable.
PAGE 2
DS4520 9-Bit I2C Nonvolatile I/O Expander Plus Memory ABSOLUTE MAXIMUM RATINGS Voltage on VCC, SDA, and SCL Pins Relative to Ground.............................................-0.5V to +6.0V Voltage on A0, A1, A2, and I/O_n [n = 0 to 8] Relative to Ground....-0.5V to (VCC + 0.5V) not to exceed +6.0V Operating Temperature Range ...........................-40°C to +85°C EEPROM Programming Temperature Range .........0°C to +70°C Storage Temperature Range .............................
PAGE 3
9-Bit I2C Nonvolatile I/O Expander Plus Memory DS4520 AC ELECTRICAL CHARACTERISTICS (See Figure 2) (VCC = +2.7V to +5.5V; TA = -40°C to +85°C, unless otherwise noted. Timing referenced to VIL(MAX) and VIH(MIN).) PARAMETER SYMBOL CONDITIONS TYP UNITS 400 kHz fSCL Bus Free Time Between Stop and Start Conditions tBUF 1.3 µs tHD:STA 0.6 µs tLOW 1.3 µs Low Period of SCL High Period of SCL 0 MAX SCL Clock Frequency Hold Time (Repeated) Start Condition (Note 5) MIN tHIGH 0.
PAGE 4
Typical Operating Characteristics (VCC = +5.0V, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE 1.0 I/O0–I/O7 CONTROL BITS = 0 I/O0–I/O7 PULLUPS DISABLED VCC = SDA = SCL = 5V 2.0 SUPPLY CURRENT (µA) 1.5 0.5 1.5 1.0 0.5 0 0 3.0 3.5 4.0 4.5 5.0 -40 -20 0 20 40 60 SUPPLY VOLTAGE (V) TEMPERATURE (°C) SUPPLY CURRENT vs. SCL FREQUENCY I/O OUTPUT VOLTAGE vs.
PAGE 5
9-Bit I2C Nonvolatile I/O Expander Plus Memory PIN NAME 1 I/O_0 Input/Output 0. Bidirectional I/O pin. FUNCTION 2 I/O_1 Input/Output 1. Bidirectional I/O pin. 3 I/O_2 Input/Output 2. Bidirectional I/O pin. 4 I/O_3 Input/Output 3. Bidirectional I/O pin. 5 I/O_4 Input/Output 4. Bidirectional I/O pin. 6 A0 I2C Address Input. Inputs A0, A1, and A2 determine the I2C slave address of the device. 7 A1 I2C Address Input. Inputs A0, A1, and A2 determine the I2C slave address of the device.
PAGE 6
DS4520 9-Bit I2C Nonvolatile I/O Expander Plus Memory Detailed Description The DS4520 contains nine bidirectional, NV, input/output (I/O) pins, and a 64-byte EEPROM user memory. The I/O pins and user memory are accessible through an I2C-compatible serial bus. Programmable NV I/O Pins Each programmable I/O pin consists of an input and an open-collector output with a selectable internal pullup resistor. To enable the pullups for each I/O pin, write to the Pullup Enable Registers (F0h and F1h).
PAGE 7
9-Bit I2C Nonvolatile I/O Expander Plus Memory NAME TYPE 00h to 3Fh EEPROM 40 to E7h — Reserved Undefined address space for future expansion. Reads and writes to this space have no effect on the device. — E8 to EFh EEPROM Reserved — — F0h Pullup Enable 0 Pullup enable for I/O_0 to I/O_7. I/O_0 is the LSB and I/O_7 is the MSB. Set the corresponding bit to enable the pullup; clear the bit to disable the pullup. 00h F1h Pullup Enable 1 Pullup enable for I/O_8. I/O_8 is the LSB.
PAGE 8
DS4520 9-Bit I2C Nonvolatile I/O Expander Plus Memory Bit Read: At the end a write operation, the master must release the SDA bus line for the proper amount of setup time before the next rising edge of SCL during a bit read (see Figure 2). The device shifts out each bit of data on SDA at the falling edge of the previous SCL pulse and the data bit is valid at the rising edge of the current SCL pulse. Remember that the master generates all SCL clock pulses including when it is reading bits from the slave.
PAGE 9
-Bit I2C Nonvolatile I/O Expander Plus Memory Acknowledge Polling: Any time an EEPROM page is written, the DS4520 requires the EEPROM write time (tW) after the stop condition to write the contents of the page to EEPROM. During the EEPROM write time, the device does not acknowledge its slave address because it is busy. It is possible to take advantage of this phenomenon by repeatedly addressing the DS4520, which allows communication to continue as soon as the device is ready.
PAGE 10
DS4520 9-Bit I2C Nonvolatile I/O Expander Plus Memory TYPICAL I2C WRITE TRANSACTION MSB START 1 LSB 0 1 0 A2 A1 A0 R/W MSB SLAVE ACK b7 LSB b6 READ/ WRITE SLAVE ADDRESS* b5 b4 b3 b2 b1 b0 MSB SLAVE ACK b7 LSB b6 b5 b4 REGISTER ADDRESS b3 b2 b1 b0 SLAVE ACK STOP DATA *THE SLAVE ADDRESS IS DETERMINED BY ADDRESS PINS A0, A1, AND A2.