AD7924BRUZ-REEL7 Analog Devices Inc, AD7924BRUZ-REEL7 Datasheet - Page 19

• Manufacturer Part Number: AD7924BRUZ-REEL7
• Description: IC,Data Acquisition System,4-CHANNEL,12-BIT,TSSOP,16PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of AD7924BRUZ-REEL7

• Number Of Bits: 12
• Sampling Rate (per Second): 1M
• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 13.5mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP (0.173", 4.40mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-AD79X4CBZ - BOARD EVALUATION FOR AD79X4CBZ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DOUT
Powering Up the AD7904/AD7914/AD7924
When supplies are first applied to the AD7904/AD7914/AD7924,
the ADC may power up in any of the operating modes of the
part. To ensure the part is placed into the required operating
mode the user should perform a dummy cycle operation as
outlined in Figures 14a through 14c.
The dummy conversion operation must be performed to place the
part into the desired mode of operation. To ensure the part is in
normal mode, this dummy cycle operation can be performed with
the DIN line tied HIGH, i.e., PM1, PM0 = 1,1 (depending on
other required settings in the control register) but the minimum
power-up time of 1 µs must be allowed from the rising edge
of CS, where the control register is updated, before attempting
the first valid conversion. This is to allow for the possibility that
the part initially powered up in shutdown. If the desired mode
of operation is Full Shutdown, then again only one dummy cycle
is required after supplies are applied. In this dummy cycle the
user simply sets the power management bits, PM1, PM0 = 1,0
and upon the rising edge of CS at the end of that serial transfer
the part will enter full shutdown.
REV. 0
SCLK
DOUT
DIN
SCLK
CS
PART IS IN FULL
SHUTDOWN
DIN
CS
CHANNEL IDENTIFIER BITS + CONVERSION RESULT
CONTROL REGISTER IS LOADED ON THE
FIRST 12 CLOCKS, PM1
1
CONTROL REGISTER IS LOADED ON THE
FIRST 12 CLOCKS. PM1 = 1, PM0 = 1
DATA IN TO CONTROL REGISTER
1
DATA IN TO CONTROL REGISTER
0, PM0
12
PART ENTERS
SHUTDOWN ON CS
RISING EDGE AS
PM1
1
0, PM0
16
Figure 13. Auto Shutdown Mode Operation
PART BEGINS TO POWER UP ON
CS RISING EDGE AS PM1 = PM0 = 1
Figure 12. Full Shutdown Mode Operation
1
PART BEGINS
TO POWER
UP ON CS
FALLING EDGE
CONTROL REGISTER CONTENTS SHOULD
NOT CHANGE, WRITE BIT
1
14
DUMMY CONVERSION
16
INVALID DATA
–19–
t
If the desired mode of operation is Auto Shutdown after sup-
plies are applied, then two dummy cycles will be required, the
first with DIN tied high and the second dummy cycle to set the
power management bits PM1 and PM0 = 0,1. On the second
CS rising edge after the supplies are applied, the Control Regis-
ter will contain the correct information and the part will enter
Auto Shutdown mode as programmed. If power consumption is
of critical concern, then in the first dummy cycle the user may
set PM1, PM0 = 1,0, i.e., Full Shutdown, and then place the
part into Auto Shutdown in the second dummy cycle. For illus-
tration purposes, Figure 14c is shown with DIN tied high on the
first dummy cycle in this case.
Figures 14a, 14b, and 14c each show the required dummy cycle(s)
after supplies are applied in the case of Normal mode, Full
Shutdown mode, or Auto Shutdown mode, respectively, being
the desired mode of operation.
12
0
12
THE PART IS FULLY POWERED UP
ONCE
1
TO KEEP THE PART IN NORMAL MODE, LOAD
PM1 = PM0 = 1 IN CONTROL REGISTER
t
16
POWER UP
CHANNEL IDENTIFIER BITS + CONVERSION RESULT
HAS ELAPSED
PART IS FULLY
POWERED UP
AD7904/AD7914/AD7924
DATA IN TO CONTROL REGISTER
CHANNEL IDENTIFIER BITS + CONVERSION RESULT
TO KEEP PART IN THIS MODE, LOAD PM1
IN CONTROL REGISTER OR SET WRITE BIT = 0
1
DATA IN TO CONTROL REGISTER
12
PART ENTERS
SHUTDOWN ON CS
RISING EDGE AS
PM1
14
0, PM0
16
16
0, PM0
1
1