Datasheet

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LTC2655

2655f

BLOCK DIAGRAM

FEATURES DESCRIPTION

Quad I

C 16-/12-Bit

Rail-to-Rail DACs with

10ppm/°C Max Reference

The LTC

2655 is a family of Quad I

C 16-/12-Bit Rail-to-

Rail DACs with integrated 10ppm/°C max reference. The

DACs have built-in high performance, rail-to-rail, output

buffers and are guaranteed monotonic. The LTC2655-L

has a full-scale output of 2.5V with the integrated refer-

ence and operates from a single 2.7V to 5.5V supply.

The LTC2655-H has a full-scale output of 4.096V with

the integrated reference and operates from a 4.5V to

5.5V supply. Each DAC can also operate with an external

reference, which sets the full-scale output to 2 times the

external reference voltage.

The parts use the 2-wire I

C compatible serial interface.

The LTC2655 operates in both the standard mode (maxi-

mum clock rate of 100kHz) and the fast mode (maximum

clock rate of 400kHz). The LTC2655 incorporates a

power-on reset circuit that is controlled by the PORSEL

pin. If PORSEL is tied to GND the DACs power-on reset to

zero-scale. If PORSEL is tied to V

, the DACs power-on

reset to mid-scale.

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents including 5396245, 6891433 and 7671770.

INL Curve

APPLICATIONS

Integrated Reference 10ppm/°C Max

Maximum INL Error: ±4LSB at 16 Bits

Guaranteed Monotonic Over Temperature

Selectable Internal or External Reference

2.7V to 5.5V Supply Range (LTC2655-L)

Integrated Reference Buffers

Ultralow Crosstalk Between DACs (<1nV•s)

Power-On-Reset to Zero-Scale/Mid-Scale

Asynchronous DAC Update Pin

Tiny 20-Lead 4mm × 4mm QFN and

16-Lead Narrow SSOP packages

Mobile Communications

Process Control and Industrial Automation

Instrumentation

Automatic Test Equipment

Automotive

2655 BD

GND

OUTA

OUTB

SCL

CA2

LDAC

REFLO

CA1

CA0

REFIN/OUT

REFCOMP

OUTD

OUTC

PORSEL

SDA

INTERNAL REFERENCE

DAC A

POWER-ON

RESET

DAC B

DAC D

DAC C

32-BIT SHIFT REGISTER

2-WIRE INTERFACE

REGISTERREGISTER

CODE

128

INL (LSB)

–2

–1

–3

–4

32768 4915216384

2655 TA01b

65535

= 5V

Summary of content (28 pages)

PAGE 1
LTC2655 Quad I2C 16-/12-Bit Rail-to-Rail DACs with 10ppm/°C Max Reference DESCRIPTION FEATURES n n n n n n n n n n The LTC®2655 is a family of Quad I2C 16-/12-Bit Rail-toRail DACs with integrated 10ppm/°C max reference. The DACs have built-in high performance, rail-to-rail, output buffers and are guaranteed monotonic. The LTC2655-L has a full-scale output of 2.5V with the integrated reference and operates from a single 2.7V to 5.5V supply. The LTC2655-H has a full-scale output of 4.
PAGE 2
LTC2655 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) Supply Voltage (VCC) ................................... –0.3V to 6V SCL, SDA, LDAC, REFLO .............................. –0.3V to 6V VOUTA to VOUTD ................–0.3V to Min (VCC + 0.3V, 6V) REFIN/OUT, REFCOMP .....–0.3V to Min (VCC + 0.3V, 6V) PORSEL, CA0, CA1, CA2 ..–0.3V to Min (VCC + 0.3V, 6V) Operating Temperature Range LTC2655C ................................................ 0°C to 70°C LTC2655I .............................................
PAGE 3
LTC2655 ORDER INFORMATION LTC2655 B C UF –L 16 #TR PBF LEAD FREE DESIGNATOR TAPE AND REEL TR = Tape and Reel RESOLUTION 16 = 16-Bit 12 = 12-Bit FULL-SCALE VOLTAGE, INTERNAL REFERENCE MODE L = 2.5V H = 4.
PAGE 4
LTC2655 PRODUCT SELECTION GUIDE TEMPERATURE RANGE MAXIMUM INL 16-Lead Narrow SSOP 0°C to 70°C ±4 16-Lead Narrow SSOP –40°C to 85°C ±4 20-Lead (4mm × 4mm) Plastic QFN 0°C to 70°C ±4 20-Lead (4mm × 4mm) Plastic QFN –40°C to 85°C ±4 16-Lead Narrow SSOP 0°C to 70°C ±4 655H16 16-Lead Narrow SSOP –40°C to 85°C ±4 LTC2655BCUF-H16#TRPBF 55H16 20-Lead (4mm × 4mm) Plastic QFN 0°C to 70°C ±4 LTC2655BIUF-H16#TRPBF 55H16 20-Lead (4mm × 4mm) Plastic QFN –40°C to 85°C ±4 LTC2655CGN-L12#TRPBF
PAGE 5
LTC2655 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VCC = 2.7V to 5.5V, VOUT unloaded unless otherwise speciﬁed. LTC2655B-L16/ LTC2655-L12 (Internal Reference=1.25V) LTC2655-12 SYMBOL PARAMETER CONDITIONS MIN TYP LTC2655B-16 MAX MIN TYP MAX UNITS DC Performance Resolution l 12 12 16 Bits Monotonicity (Note 3) l DNL Differential Nonlinearity (Note 3) l ±0.1 ±0.5 ±0.
PAGE 6
LTC2655 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VCC = 2.7V to 5.5V, VOUT unloaded unless otherwise speciﬁed. LTC2655B-L16/LTC2655-L12 (Internal Reference = 1.25V) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 1.248 1.25 1.
PAGE 7
LTC2655 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VCC = 4.5V to 5.5V, VOUT unloaded unless otherwise speciﬁed. LTC2655B-H16/LTC2655-H12 (Internal Reference = 2.048V) LTC2655-12 SYMBOL PARAMETER CONDITIONS MIN TYP LTC2655B-16 MAX MIN TYP MAX UNITS DC Performance Resolution DNL INL l 12 12 16 Monotonicity (Note 3) l Differential Nonlinearity (Note 3) l ±0.
PAGE 8
LTC2655 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VCC = 4.5V to 5.5V, VOUT unloaded unless otherwise speciﬁed. LTC2655B-H16/LTC2655-H12 (Internal Reference = 2.048V) SYMBOL PARAMETER CONDITIONS MIN TYP MAX 2.044 UNITS Reference Reference Output Voltage 2.048 2.
PAGE 9
LTC2655 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VCC = 2.7V to 5.5V (LTC2655B-L16/LTC2655-L12), VCC = 4.5V to 5.5V (LTC2655B-H16, LTC2655-H12), VOUT unloaded unless otherwise speciﬁed. LTC2655B-L16/LTC2655-L12/LTC2655B-H16/LTC2655-H12 SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS AC Performance ts Settling Time ( Note 10) ±0.024%(±1LSB at 12 Bits) ±0.0015%(±1LSB at 16 Bits) 3.9 9.
PAGE 10
LTC2655 ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: All voltages are with respect to GND. Note 3: Linearity and monotonicity are deﬁned from code kL to code 2N–1, where N is the resolution and kL is the lower end code for which no output limiting occurs. For VREF = 2.
PAGE 11
LTC2655 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. LTC2655-L16 Integral Nonlinearity (INL) 4 Differential Nonlinearity (DNL) 1.0 VCC = 3V VCC = 3V 3 0.5 1 DNL (LSB) INL (LSB) 2 0 –1 –2 0 –0.5 –3 –4 128 16384 32768 CODE –1.0 128 65535 49152 16384 32768 CODE 49152 2655 G01 4 2655 G02 REFIN/OUT Output Voltage vs Temperature DNL vs Temperature INL vs Temperature 1.0 VCC = 3V 1.253 VCC = 3V 3 1.252 1.251 0 –1 DNL(POS) VREF (V) 1 –2 VCC = 3V 0.
PAGE 12
LTC2655 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. LTC2655-H16 Integral Nonlinearity (INL) 4 Differential Nonlinearity (DNL) 1.0 VCC = 5V VCC = 5V 3 0.5 1 DNL (LSB) INL (LSB) 2 0 –1 –2 0 –0.5 –3 –4 128 16384 32768 CODE –1.0 128 65535 49152 16384 32768 CODE 49152 2655 G08 INL vs Temperature 4 2655 G09 Reference Output Voltage vs Temperature DNL vs Temperature 1.0 VCC = 3V 2.054 VCC = 3V 3 0.5 2.050 0 –1 DNL(POS) VREF (V) 1 –2 VCC = 5V 2.
PAGE 13
LTC2655 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. LTC2655-12 1.0 VCC = 5V VREF = 2.048V DNL (LSB) INL (LSB) VCC = 3V VREF = 1.25V SCL 3V/DIV 0.5 0.5 0 4.0μs 0 VOUT 1mV/DIV –0.5 –0.5 –1.0 Settling to ±1LSB Falling Differential Nonlinearity (INL) Integral Nonlinearity (INL) 1.0 –1.0 8 1024 2048 CODE 3072 4095 3/4 TO 1/4 SCALE STEP VCC = 3V, VFS = 2.
PAGE 14
LTC2655 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. LTC2655 Gain Error vs Reference Input Offset Error vs Reference Input LTC2655-16 48 VCC = 5.5V GAIN ERROR OF 4 CHANNELS 1.0 32 0.5 0 –0.5 350 300 0 –16 –32 –1.5 –48 50 1 1.5 2 REFERENCE VOLTAGE (V) 4.5 5.5 5 ICC Shutdown vs Temperature VCC = 5V (LTC2655-H) 2.0 VCC = 3V (LTC2655-L) 2.5 2.0 1.5 1.
PAGE 15
LTC2655 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. LTC2655 DAC to DAC Crosstalk (Dynamic) ONE DAC SWITCH 0-FS 1V/DIV Power-On Reset Glitch VCC 2V/DIV ZERO-SCALE VOUT 10mV/DIV VOUT 0.5mV/DIV LTC2655-L16, VCC = 5V, 0.4nV•s TYP CREFCOMP = CREFOUT = 0.
PAGE 16
LTC2655 PIN FUNCTIONS (GN/UF) REFLO (Pin 1/Pin 20): Reference Low. The voltage at this pin sets the zero-scale voltage of all DACs. This pin should be tied to GND. VOUTA to VOUTD (Pins 2,4,13,14/Pins 1, 3, 13, 14): DAC Analog Voltage Outputs. The output range is 0V to 2 times the voltage at the REFIN/OUT pin. REFCOMP (Pin 3/Pin 2): Internal Reference Compensation. For low noise and reference stability, tie 0.1μF capacitor to GND. Connect to GND to use an external reference at start-up.
PAGE 17
LTC2655 BLOCK DIAGRAM REFCOMP REFIN/OUT INTERNAL REFERENCE GND VCC REGISTER REGISTER REGISTER DAC B REGISTER REGISTER CA0 DAC D REGISTER VOUTB DAC A REGISTER VOUTA REGISTER REFLO DAC C CA1 32-BIT SHIFT REGISTER CA2 SCL POWER-ON RESET VOUTD VOUTC PORSEL SDA 2-WIRE INTERFACE LDAC 2655 BD 2655f 17
PAGE 18
LTC2655 TEST CIRCUITS Test Circuit 1 100Ω CAn VIH(CAn)/VIL(CAn) 2655 TC01 Test Circuit 2 VDD RINH/RINL/RINF 2655 TC02 GND TIMING DIAGRAM SDA tf tLOW tSU(DAT) tr tf tHD(STA) tSP tr tBUF SCL S tHD(STA) tHD(DAT) tHIGH tSU(STA) S tSU(STO) P S 2655 F01 ALL VOLTAGE LEVELS REFER TO VIH(MIN) AND VIL(MAX) LEVELS 9TH CLOCK OF 3RD DATA BYTE SCL t1 LDAC Figure 1 2655f 18
PAGE 19
LTC2655 OPERATION The LTC2655 is a family of quad voltage output DACs in 20-lead 4mm × 4mm QFN and in 16-lead narrow SSOP packages. Each DAC can operate rail-to-rail in external reference mode, or with its full-scale voltage set by an integrated reference. Four combinations of accuracy (16-bit and 12-bit), and full-scale voltage (2.5V or 4.096V) are available. The LTC2655 is controlled using a 2-wire I2C compatible interface.
PAGE 20
LTC2655 OPERATION necessary if the bus capacitance is greater than 200pF. The LTC2655 is a receive-only (slave) device. The master can write to the LTC2655. The LTC2655 does not respond to a read command from the master. The START (S) and STOP (P) Conditions When the bus is not in use, both SCL and SDA must be high. A bus master signals the beginning of a communication to a slave device by transmitting a START condition (see Figure 1).
PAGE 21
LTC2655 OPERATION Write Word Protocol Power-Down Mode The master initiates communication with the LTC2655 with a START condition and a 7-bit slave address followed by the Write bit (W) = 0. The LTC2655 acknowledges by pulling the SDA pin low at the 9th clock if the 7-bit slave address matches the address of the part (set by CA0, CA1 and CA2) or the global address. The master then transmits three bytes of write data.
PAGE 22
LTC2655 OPERATION In this case, the power-up delay time is approximately 14μs. The power-up of the integrated reference depends on the command that powered it down. If the reference is powered down using the Select External Reference command (0111b), then it can only be powered back up by sending the Select Internal Reference command (0110b).
PAGE 23
LTC2655 OPERATION Board Layout Rail-to-Rail Output Considerations The excellent load regulation and DC crosstalk performance of these devices is achieved in part by keeping signal and power grounds separate. In any rail-to-rail voltage output device, the output is limited to voltages within the supply range. The PC board should have separate areas for the analog and digital sections of the circuit.
PAGE 24
2 1 SCL VOUT SA5 SA6 SA5 3 SA4 4 SA3 SA3 5 SA2 SA2 6 SA1 SA1 SLAVE ADDRESS SA4 7 SA0 SA0 8 WR 1 C3 2 C2 C2 3 C1 C1 4 C0 C0 5 A3 A3 COMMAND 6 A2 A2 7 A1 A1 8 A0 A0 9 ACK 1 D15 2 D14 3 D13 4 5 D11 MS DATA D12 6 D10 7 D9 8 D8 9 ACK 1 D7 2 D6 Figure 2.
PAGE 25
LTC2655 OPERATION POSITIVE FSE VREF = VCC VREF = VCC OUTPUT VOLTAGE OUTPUT VOLTAGE INPUT CODE (c) OUTPUT VOLTAGE 0 65, 535 (a) 0V NEGATIVE OFFSET 32, 768 INPUT CODE INPUT CODE (b) 2655 F03 Figure 3. Effects of Rail-to-Rail Operation On a DAC Transfer Curve.
PAGE 26
LTC2655 PACKAGE DESCRIPTION GN Package 16-Lead Plastic SSOP (Reference LTC DWG # 05-08-1641) .189 – .196* (4.801 – 4.978) .045 ±.005 16 15 14 13 12 11 10 9 .254 MIN .009 (0.229) REF .150 – .165 .229 – .244 (5.817 – 6.198) .0165 ± .0015 .150 – .157** (3.810 – 3.988) .0250 BSC RECOMMENDED SOLDER PAD LAYOUT 1 .015 ± .004 × 45° (0.38 ± 0.10) .007 – .0098 (0.178 – 0.249) .0532 – .0688 (1.35 – 1.75) 2 3 4 5 6 7 8 .004 – .0098 (0.102 – 0.249) 0° – 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1.
PAGE 27
LTC2655 PACKAGE DESCRIPTION UF Package 20-Lead (4mm × 4mm) Plastic QFN (Reference LTC DWG # 05-08-1710 Rev A) 0.70 ±0.05 4.50 ± 0.05 3.10 ± 0.05 2.00 REF 2.45 ± 0.05 2.45 ± 0.05 PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 4.00 ± 0.10 0.75 ± 0.05 R = 0.05 TYP R = 0.115 TYP 19 20 0.40 ± 0.10 PIN 1 TOP MARK (NOTE 6) 4.00 ± 0.10 PIN 1 NOTCH R = 0.20 TYP OR 0.35 × 45° CHAMFER BOTTOM VIEW—EXPOSED PAD 1 2.00 REF 2.
PAGE 28
LTC2655 TYPICAL APPLICATION ±5V Bipolar Output DAC +5V C2 0.1μF 3 C1 +5V 0.1μF C3 0.