ISL29020IROZ-T7 Datasheet ISL29020IROZ-EVALZ, ISL29020IROZ-T7A, ISL29020IROZ-T7 | P4-P6

FN6505.1

August 20, 2009

FIGURE 1. I

C READ TIMING DIAGRAM SAMPLE

START

A A

A6 A5 A4 A3 A2 A1 A0 W

A R7 R6 R5 R4 R3 R2 R1 R0 A A6 A5 A4 A3 A2 A1 A0 W A

A A AD7D6D5D4D3D2D1D0

1357

123456 9 2 4 6

STOP START

SDA DRIVEN BY MASTER

DEVICE ADDRESS

SDA DRIVEN BY ISL29020

DATA BYTE0REGISTER ADDRESSDEVICE ADDRESSI

C DATA

SDA DRIVEN BY MASTER

2468

924689

78135789

C SDA IN

C SDA OUT

C CLK

FIGURE 2. I

C WRITE TIMING DIAGRAM SAMPLE

START W A A

A6 A5 A4 A3 A2 A1 A0 W

A R7 R6 R5 R4 R3 R2 R1 R0 A B7 B6 B5 B4 B3 B2 B1 B0 A

12615948

STOP

SDA DRIVEN BY MASTER

FUNCTIONSREGISTER ADDRESSDEVICE ADDRESS

SDA DRIVEN BY MASTER

C DATA

C SDA IN

C SDA OUT

C CLK IN

345 789 234 678 123 567 9

FIGURE 3. I

C SYNC_I

C TIMING DIAGRAM SAMPLE

A 6 A5 A4 A3 A2 A1 A0 W A R7R6R5R4R3R2R1R0 A

15 4

START W ASTOPREGISTER ADDRESSDEVICE ADDRESS AREGISTER ADDRESSREGISTER ADDRESSI

C DATA

C SDA IN

C SDA OUT

C CLK IN

SDA DRIVEN BY MASTER SDA DRIVEN BY MASTER A

234 6789123 56789

ISL29020

FN6505.1

August 20, 2009

There are three 8-bit registers in the ISL29020. Table 1 summarizes their functions.

Command Register (00 hex)

The Read/Write command register has five functions:

1. Enable: Bit 7. This bit enables the ISL29020 with logic 1

and powers down ISL29020 with logic 0.

2. Measurement Mode: Bit 6. This bit controls the two

measurement modes of the device. A logic 0 puts the

device in the one-time measurement mode in which the

device is automatically shut-down after each

measurement. A logic 1 puts the device in the continuous

measurement mode in which data is collected

continuously.

3. Light Sensing: Bit 5. This bit programs the device to do the

ambient light or the infrared (IR) light sensing. A logic 0,

requests for the ambient light sensing and a logic 1

requests for the IR sensing.

4. Timing Mode and Resolution: Bits 4, 3 and 2. These three

bits determine whether the integration time is done

internally or externally, and the number of bits for ADC. In

Internal Timing Mode, integration time is determined by

an internal oscillator (f

OSC

) and the n-bit (n = 4, 8, 12, 16)

counter inside the ADC. In External Timing Mode, the

integration time is determined by the time between two

consecutive sync_I

C pulse commands.

With Bit 4 set to 0, the device is configured to run in the

Internal-Timing mode. For example, the command register

content should be 1xx000xx to request 16-bit ADC in the

internal-timing mode.

With Bit 4 set to 1, the device is configured to run in the

External-Timing mode. For the external timing, the command

1xx101xx needs to be sent to request the Timer data, the

number of clock cycles counted within the duration between

the two sync pulses (refer to Table 2). The Timer count is

read from register 01h (LSB) and 02h (MSB). The command

1xx100xx needs to be sent to request the ADC conversion.

The ADC data is also read from register 01h (LSB) and 02h

(MSB).

Bits 3 and 2 determine the number of clock cycles per

conversion in the Internal-Timing mode. Changing the

number of clock cycles does more than just change the

resolution of the device. It also changes the integration

time, which the ADC uses to sample the photodiode

current signal for a measurement.

TABLE 1. REGISTER SET

ADDR REG NAME

BIT

DEFAULT765 4 3210

00h COMMAND EN MODE LIGHT RES2 RES1 RES0 RANGE1 RANGE0 00h

01h DATA

LSB

D7 D6 D5 D4 D3 D2 D1 D0 00h

02h DATA

MSB

D15 D14 D13 D12 D11 D10 D9 D8 00h

TABLE 2. WRITE ONLY REGISTERS

ADDRESS NAME FUNCTIONS/DESCRIPTION

b1xxx_xxxx sync_I

C Writing a logic 1 to this address bit

ends the current ADC-integration

and starts another. Used only with

External Timing Mode.

TABLE 3. ENABLE

BIT 7 OPERATION

0 Power-down the device

1 Enable the device

TABLE 4. MEASUREMENT MODE

BIT 6 OPERATION

0 One-time measurement

1 Continuous measurement

TABLE 5. LIGHT SENSING

BIT 5 OPERATION

0 Ambient light sensing

1 Infrared light sensing

TABLE 6. TIMING MODE AND RESOLUTION

BITS 4:3:2 MODE

0:0:0 Internal Timing, 16-bit ADC data output

0:0:1 Internal Timing, 12-bit ADC data output

0:1:0 Internal Timing, 8-bit ADC data output

0:1:1 Internal Timing, 4-bit ADC data output

1:0:0 External Timing, ADC data output

1:0:1 External Timing, Timer data output

1:1:0 Reserved

1:1:1 Reserved

ISL29020

FN6505.1

August 20, 2009

5. Range: Bits 1 and 0. The Full Scale Range (FSR) can be

adjusted via I

C using Bits 1 and 0. Table 8 lists the

possible values of FSR for the 500kΩ R

EXT

resistor.

Data Registers (01 hex and 02 hex)

The device has two 8-bit read-only registers to hold a 16-bit

data from ADC or Timer. The most significant byte is

accessed at 02 hex, and the least significant byte is

accessed at 01 hex. The registers are refreshed after every

conversion cycle.

Calculating Lux

The ISL29020’s ADC output codes, DATA, are directly

proportional to lux in the ambient light sensing, as shown in

Equation 1.

Here, E

cal

is the calculated lux reading. The constant α is

determined by the Full Scale Range and the ADC’s

maximum output counts. The constant can also be viewed

as the sensitivity: the smallest lux measurement the device

can measure, as shown in Equation 2.

Here, Range(k) is defined in Table 8. Count

max

is the

maximum output counts from the ADC.

The transfer function used for each timing mode becomes:

INTERNAL TIMING MODE

Here, n = 4, 8, 12 or 16. This is the number of ADC bits

programmed in the command register. 2

represents the

maximum number of counts possible from the ADC output in

Internal-Timing mode. Data is the ADC output stored in the

data registers (01 hex and 02 hex).

EXTERNAL TIMING MODE

Here, Timer sets up the ADC’s maximum count reading and

it is the number of clock cycles accrued in the integration

time (set by sync_I

C pulses) in External-Timing mode. It is

stored in the data registers 01h and 02h when the command

is coded as 1xx101xx. Data is the ADC output. In this mode,

the command has to be sent out again with code 1xx100xx

to request the ADC output data from registers 01h and 02h.

External Scaling Resistor R

EXT

for f

OSC

and

Range

The ISL29020 uses an external resistor R

EXT

to fix its

internal oscillator frequency, f

OSC

and the light sensing

range, Range. f

OSC

and Range are inversely proportional to

EXT

. For user simplicity, the proportionality constant is

referenced to 500kΩ:

Integration Time or Conversion Time

Integration time is the period during which the device’s

analog-to-digital ADC converter samples the photodiode

current signal for a measurement. Integration time, in other

words, is the time to complete the conversion of analog

photodiode current into a digital signal (number of counts).

Integration time affects the measurement resolution. For

better resolution, use a longer integration time. For short and

fast conversions, use a shorter integration time.

The ISL29020 offers user flexibility in the integration time to

balance resolution, speed and noise rejection. Integration time

can be set internally or externally by programming the bit 4 of

the command register 00(hex).

INTEGRATION TIME IN INTERNAL-TIMING MODE

Most applications will use the Internal-Timing mode. In this

mode, f

OSC

and ADC n-bits resolution determine the

integration time, t

int,

as shown in Equation 7.

where n is the number of bits of resolution and n = 4, 8, 12 or

16. 2

, therefore, is the number of clock cycles. n can be

programmed at the command register 00(hex) bits 3 and 2.

TABLE 7. RESOLUTION/WIDTH

BITS 3:2 NUMBER OF CLOCK CYCLES

0:0 2

= 65,536

0:1 2

= 4,096

1:0 2

= 256

1:1 2

= 16

TABLE 8. RANGE/FSR LUX

BITS

1:0 k RANGE(k)

FSR (LUX) @

ALS SENSING

FSR (LUX) @ IR

SENSING

0:0 1 Range1 1,000 Refer to page 2

0:1 2 Range2 4,000 Refer to page 2

1:0 3 Range3 16,000 Refer to page 2

1:1 4 Range4 64,000 Refer to page 2

TABLE 9. DATA REGISTERS

ADDRESS

(hex) CONTENTS

01 Least-significant byte of most recent ADC or Timer data.

02 Most-significant byte of most recent ADC or Timer data.

cal

α DATA×=

(EQ. 1)

Range k()

Count

max

----------------------------

(EQ. 2)

(EQ. 3)

Range k()

---------------------------

DATA×=

(EQ. 4)

Range k()

Timer

---------------------------

DATA×=

(EQ. 5)

Range

500kΩ

EXT

------------------

Range k()×=

(EQ. 6)

OSC

500kΩ

EXT

------------------

725× kHz=

int

OSC

--------------

× 2

EXT

725kHz 500kΩ×

----------------------------------------------

×==

(EQ. 7)

ISL29020

P1-P3 P4-P6 P7-P9 P10-P11

ISL29020IROZ-T7

Mfr. #:

Buy ISL29020IROZ-T7

Manufacturer:

Renesas / Intersil

Description:

Optical Sensors Light to Digital Converters ISL29020IROZ LW PWR DIGTL OUTPUT LT SNSR

Lifecycle:

New from this manufacturer.

Delivery:

DHL FedEx Ups TNT EMS

Payment:

T/T Paypal Visa MoneyGram Western Union

ISL29020IROZ-T7

ISL29020IROZ-T7

Products related to this Datasheet