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ICmic
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
with guaranteed monotonic behavior. These DACs are available in both a tiny 6-pin SOT-23 package and an 8pin MSOP package. They include a 1.25V reference for ease of use and flexibility. The reference output is available on a separate pin, in the 8-pin package version, and can be used to drive external loads. The operating supply range is 2.7V to 5.5V. The input interface is an easy to use three-wire SPI/QSPI compatible interface. The DAC has a double buffered digitalkinput.
FEATURES * 12/10/8-Bit Monotonic DACs in 6 lead SOT-23 Package * Wide Output Voltage Swing * Micro-Power * On Board 1.25V Reference * Serial Interface with three-wire SPI/QSPI and Microwire Interface Compatible * 8s Full-Scale Settling Time APPLICATIONS * Battery-Powered Applications * Industrial Process Control * Digital Gain and Offset Adjustment OVERVIEW The ICM7361, ICM7341 and ICM7321 are 12-Bit, 10-Bit and 8-Bit wide output voltage swing DACs respectively,
BLOCK DIAGRAM
VDD ICM 7361/7341/7321
REFOUT
(MSOP-8 Package Only)
Reference
Input and DAC Latch
12/10/8 -Bit DAC
x2
VOUT
SDI
Input Control Logic, Registers and Latches Power-OnReset SCK CS GND
PACKAGE SOT-23 8-Pin MSOP
VOUT 1 GND 2 VDD 3
6 CS 5 SCK 4 SDI
VDD 1 REFOUT 2 NC 3 VOUT 4
8 GND 7 SDI 6 SCK 5 CS
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
1
ICmic
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
PIN DESCRIPTION (MSOP-8 Package)
Pin No 1 2 3 4 VDD
Symbol Supply Voltage Reference Output (1.25V) No Connect DAC Output
Description
REFOUT NC VOUT CS SCK SDI GND
5 6 7 8
Chip Select (TTL or CMOS) Serial Clock Input (TTL or CMOS) Serial Data Input (TTL or CMOS) Ground
PIN DESCRIPTION (SOT-23 Package)
Pin No 1 2 3 VOUT
Symbol DAC Output Ground Supply Voltage
Description
GND VDD
4 5
SDI SCK
Serial Data Input (TTL or CMOS) Serial Clock Input (TTL or CMOS)
6
CS
Chip Select (TTL or CMOS)
ABSOLUTE MAXIMUM RATING
Symbol VDD IIN VIN_ VIN_REF TSTG TSOL Supply Voltage Input Current
Parameter
Value -0.3 to 7.0 +/- 25.0 -0.3 to 7.0 -0.3 to 7.0 -65 to +150 300 V
Unit
mA V V
o o
Digital Input Voltage (SCK, SDI, CS) Reference Input Voltage Storage Temperature Soldering Temperature
C C
Note: Stress greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
2
ICmic
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
ORDERING INFORMATION
Part ICM7361M ICM7341M ICM7321M
Temperature Range -40 oC to 85 oC -40 oC to 85 oC -40 oC to 85 oC
Package 8-Pin MSOP 8-Pin MSOP 8-Pin MSOP
ORDERING INFORMATION
Part ICM7361T ICM7341T ICM7321T
o
Temperature Range -40 C to 85 C -40 oC to 85 oC -40 oC to 85 oC
o
Package SOT-23 SOT-23 SOT-23
DC ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V ; VOUT unloaded; all specifications TMIN to TMAX unless otherwise noted) Symbol Parameter Test Conditions Min Typ Max Unit
DC PERFORMANCE ICM7361 N Resolution DNL Differential Nonlinearity INL Integral Nonlinearity ICM7341 N Resolution DNL Differential Nonlinearity INL Integral Nonlinearity ICM7321 N Resolution DNL Differential Nonlinearity INL Integral Nonlinearity GE Gain Error OE Offset Error POWER REQUIREMENTS VDD Supply Voltage IDD Supply Current
12 (Notes 1 & 3) (Notes 1 & 3) 10 (Notes 1 & 3) (Notes 1 & 3) 8 (Notes 1 & 3) (Notes 1 & 3) 0.05 0.25 +1.0 +0.75 +0.5 +25 2.7 (Note 4) 0.2 5.5 0.5 0.1 1.0 +1.0 +3.0 0.4 4.0 +1.0 +12.0
Bits LSB LSB Bits LSB LSB Bits LSB LSB % of FS mV V mA
Symbol
Parameter
Test Conditions
Min
Typ
Max
Unit
OUTPUT CHARACTERISTICS Output Voltage Range VOSC Short Circuit Current ROUT Amp Output Impedance Output Line Regulation LOGIC INPUTS VIH Digital Input High VIL Digital Input Low Digital Input Leakage
(Note 3) At Mid-scale (Note 2) At 0-scale (Note 2) VDD =2.7 to 5.5 V (Note 2) (Note 2)
0 60 1.0 100 0.4 2.4
VDD 150 5.0 200 3.0
V mA mV/V V V
0.8 5
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
3
ICmic
REFERENCE VREFOUT
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
Reference Output Reference Output Line Regulation
1.2 VDD =2.7 to 5.5 V
1.25 0.8
1.3 4.0
V mV/V
AC ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V; VOUT unloaded; all specifications TMIN to TMAX unless otherwise noted) Symbol SR Parameter Slew Rate Settling Time Mid-scale Transition Glitch Energy Full-scale settling Test Conditions Min 2 8 Typ Max Unit V/s s
40
nV-S
Note 1: Note 2: Note 3: Note 4:
Linearity is defined from code 64 to 4095 (ICM7361) Linearity is defined from code 16 to 1023 (ICM7341) Linearity is defined from code 4 to 255 (ICM7321) Guaranteed by design; not tested in production See Applications Information All digital inputs are either at GND or VDD
TIMING CHARACTERISTICS (VDD = 2.7V to 5.5V; all specifications TMIN to TMAX unless otherwise noted) Symbol t1 t2 t3 t4 t5 Parameter SCK Cycle Time Data Setup Time Data Hold Time SCK Falling edge to CS Rising Edge CS Falling Edge to SCK Rising Edge (Note 2) t6 CS Pulse Width 20 ns Test Conditions (Note 2) (Note 2) (Note 2) (Note 2) (Note 2) 15 ns Min 30 10 10 0 Typ Max ns ns ns ns Unit
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
4
ICmic
SCK
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
t1
t3 t2
SDI
C3
C2
MSB
t5
Input Word for DAC N
t4
CS
t6
Figure 1: Serial Interface Timing Diagram
CONTENTS OF INPUT SHIFT REGISTER ICM7361 (12-Bit DAC) MSB C3 C2 C1 C0
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
LSB D0
Figure 2: Contents of ICM7361 Input Shift Register ICM7341 (10-Bit DAC) MSB C3 C2 C1 C0
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
X
LSB X
Figure 3: Contents of ICM7341 Input Shift Register ICM7321 (8-Bit DAC) MSB C3 C2 C1 C0
D7
D6
D5
D4
D3
D2
D1
D0
X
X
X
LSB X
Figure 4: Contents of ICM7321 Input Shift Register
C3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
C2 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1
C1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1
C0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
DATA Data Data Data X X X X X X X X X X X X X
FUNCTION Load Input Latch Update DAC Load Input Latch and Update DAC No Operation No Operation No Operation No Operation No Operation No Operation No Operation No Operation No Operation No Operation No Operation No Operation No Operation
Table 1: Serial Interface Control Command
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
5
ICmic
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
then decoded and the DAC is updated or loaded depending on the control word (see Table 1). The DAC has a double-buffered input with an input latch and a DAC latch. The DAC output will swing to its new value when data is loaded into the DAC latch. The user has three options: loading only the input latch, updating the DAC with data previously loaded into the input latch or loading the input latch and updating the DAC at the same time with a new code. Power-On Reset There is a power-on reset on board that will clear the contents of all the latches to all 0s on power-up and the DAC voltage output will go to ground.
DETAILED DESCRIPTION The ICM7361 is a 12-bit voltage output DAC. The ICM7341 is the 10-bit version of this family and the ICM7321 is the 8-bit version. This family of DACs has guaranteed monotonic behavior. There is a 1.25V onboard reference and an operating supply range of 2.7V to 5.5V. Reference Output There is an internal bandgap reference of 1.25V on these parts and there is a gain of two in the output amplifiers which means they swing from ground at code 0 to 2.5V at full-scale : Vout = 2 x (1.25 xD)/2n Where D=digital input (decimal) and n= number of bits, i.e. 12 for ICM7361, 10 for ICM7341 and 8 for ICM7321. The reference output is nominally 1.25V and is brought out to a separate pin, REFOUT (8-pin MSOP package only) and can be used to drive external loads. However, it is still internally connected to the DAC reference input. The outputs will nominally swing from 0 to 2.5V. Output Amplifier The DAC has an output amplifier with a wide output voltage swing. The actual swing of the output amplifier will be limited by offset error and gain error. See the Applications Information Section for a more detailed discussion. The amplifier is configured in a gain of 2 with internal gain resistors of about 50 k. The output swing will be from 0V to 2.5V at full-scale. The output amplifier can drive a load of 2.0 k to VDD or GND in parallel with a 500 pF load capacitance. The output amplifier has a full-scale typical settling time of 8 s and it dissipates about 100 A with a 3V supply voltage. Serial Interface and Input Logic This DAC family uses a standard 3-wire connection compatible with SPI/QSPI interfaces. Data is loaded in 16bit words which consist of 4 address and control bits (MSBs) followed by 12 bits of data (see table 1). The ICM7341 has the last two LSBs as don't cares and the ICM7321 has the last 4 LSBs as don't cares. The DAC is double buffered with an input latch and a DAC latch. All the digital inputs are CMOS/TTL compatible. The current dissipation of the device however, will be higher when the inputs are driven at TTL levels. Data is clocked in on the rising edge of SCK which has a Schmitt trigger internally to allow for noise immunity on the SCK pin. This specially eases the use for opto-coupled interfaces. The CS pin must be low when data is being clocked into the part. After the 16th clock pulse the CS pin must be pulled high (level-triggered) for the data to be transferred to an input bank of latches. The CS pin also disables the SCK pin internally when pulled high and the SCK pin must be low before the CS pin is pulled back low. As the CS pin is pulled high the shift register contents are transferred to a bank of 16 latches. The 4 bit control word (C3~C0) is
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
6
ICmic
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
input is loaded into the DAC the output will eventually rise above ground. This is why the linearity is specified for a starting code greater than zero. Figure 6 illustrates how a gain error or positive offset error will affect the output when it is close to VDD. A positive gain error or positive offset will cause the output to be limited to the positive supply voltage resulting in a dead-band of codes close to full-scale.
APPLICATIONS INFORMATION Power Supply Bypassing and Layout Considerations As in any precision circuit, careful consideration has to be given to layout of the supply and ground. The return path from the GND to the supply ground should be short with low impedance. Using a ground plane would be ideal. The supply should have some bypassing on it. A 10 F tantalum capacitor in parallel with a 0.1 F ceramic with a low ESR can be used. Ideally these would be placed as close as possible to the device. Avoid crossing digital and analog signals, specially the reference, or running them close to each other. Output Swing Limitations The ideal rail-to-rail DAC would swing from GND to VDD however, offset and gain error limit this ability. Figure 5 illustrates how a negative offset error will affect the output. The output will limit close to ground since this is single supply part, resulting in a dead-band area. As a larger
DEADBAND
NEGATIVE OFFSET
OFFSET AND GAIN ERROR
Figure 5: Effect of Negative Offset
VDD
DEADBAND
POSITIVE OFFSET
Figure 6: Effect of Gain Error and Positive Offset
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
7
ICmic
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
PACKAGE INFORMATION 8-Pin MSOP Package
SOT-23 Package
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
8
ICmic
IC MICROSYSTEMS
ICM7361/7341/7321
SINGLE 12/10/8-BIT VOLTAGE-OUTPUT DACS
ORDERING INFORMATION
ICM73X1 P G
Device 6 - ICM7361 4 - ICM7341 2 - ICM7321 G = RoHS Compliant Lead-Free package. Blank = Standard package. Non lead-free. Package M = 8-Lead MSOP S = 6-Lead SOT-23
Rev. A8
ICmic reserves the right to change the specifications without prior notice.
9

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