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LTC2637

2637fb

Octal 12-/10-/8-Bit I

C V

OUT

DACs with 10ppm/°C Reference

FEATURES

APPLICATIONS

DESCRIPTION

The LTC

2637 is a family of octal 12-, 10-, and 8-bit

voltage-output DACs with an integrated, high-accuracy,

low-drift 10ppm/°C reference in 14-lead DFN and 16-lead

MSOP packages. It has a rail-to-rail output buffer and is

guaranteed monotonic. The LTC2637-L has a full-scale

output of 2.5V, and operates from a single 2.7V to 5.5V

supply. The LTC2637-H has a full-scale output of 4.096V,

and operates from a 4.5V to 5.5V supply. Each DAC can

also operate with an external reference, which sets the DAC

full-scale output to the external reference voltage.

These DACs communicate via a 2-wire I

C-compatible

serial interface. The LTC2637 operates in both the standard

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

of 400kHz). The LTC2637 incorporates a power-on reset

circuit. Options are available for reset to zero-scale or

reset to mid-scale in internal reference mode, or reset to

mid-scale in external reference mode after power-up.

Integrated Precision Reference:

2.5V Full-Scale 10ppm/°C (LTC2637-L)

4.096V Full-Scale 10ppm/°C (LTC2637-H)

Maximum INL Error: 2.5LSB (LTC2637-12)

Low Noise: 0.75mV

P-P

0.1Hz to 200KHz

Guaranteed Monotonic Over –40°C to 125°C

Temperature Range

Selectable Internal or External Reference

2.7V to 5.5V Supply Range (LTC2637-L)

Ultralow Crosstalk Between DACs (<3nV•s)

Low Power: 100µA per DAC at 3V (LTC2637-L)

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

Double-Buffered Data Latches

Tiny 14-Lead 4mm × 3mm DFN and 16-Lead MSOP

Packages

Mobile Communications

Process Control and Industrial Automation

Automatic Test Equipment

Portable Equipment

Automotive

Optical Networking

BLOCK DIAGRAM

Integral Nonlinearity (LTC2637-LZ12)

2637 BD

GND

OUTA

OUTB

OUTC

OUTD

CAO

(CA1)

(CA2)

REF

OUTH

OUTG

OUTF

OUTE

SCL

INTERNAL REFERENCE

SWITCH

DAC A

DECODE

POWER-ON RESET

REF

DAC B

DAC C

DAC D

DAC H

DAC G

DAC F

DAC E

ADDRESS

DECODE

( ) MSOP PACKAGE ONLY

REGISTERREGISTERREGISTER

REGISTERREGISTERREGISTERREGISTER

SDA

C INTERFACE

CODE

INL (LSB)

–1

–2

1024 3072

2637 TA01

40952048

= 3V

INTERNAL REF.

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

ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property

of their respective owners. Protected by U.S. Patents including 5396245, 5859606, 6891433,

6937178, 7414561.

Summary of content (28 pages)

PAGE 1
LTC2637 Octal 12-/10-/8-Bit I2C VOUT DACs with 10ppm/°C Reference DESCRIPTION FEATURES n n n n n n n n n n n The LTC®2637 is a family of octal 12-, 10-, and 8-bit voltage-output DACs with an integrated, high-accuracy, low-drift 10ppm/°C reference in 14-lead DFN and 16-lead MSOP packages. It has a rail-to-rail output buffer and is guaranteed monotonic. The LTC2637-L has a full-scale output of 2.5V, and operates from a single 2.7V to 5.5V supply. The LTC2637-H has a full-scale output of 4.
PAGE 2
LTC2637 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) Supply Voltage (VCC) ................................... –0.3V to 6V SCL, SDA ..................................................... –0.3V to 6V VOUTA - VOUTH, CA0, CA1, CA2...................–0.3V to Min(VCC + 0.3V, 6V) REF ...................................–0.3V to Min(VCC + 0.3V, 6V) Operating Temperature Range LTC2637C ................................................ 0°C to 70°C LTC2637I .............................................
PAGE 3
LTC2637 ORDER INFORMATION LTC2637 C DE –L Z 12 #TR PBF LEAD FREE DESIGNATOR TAPE AND REEL TR = 2500-Piece Tape and Reel RESOLUTION 12 = 12-Bit 10 = 10-Bit 8 = 8-Bit POWER-ON RESET MI = Reset to Mid-Scale in Internal Reference Mode MX = Reset to Mid-Scale in External Reference Mode Z = Reset to Zero-Scale in Internal Reference Mode FULL-SCALE VOLTAGE, INTERNAL REFERENCE MODE L = 2.5V H = 4.
PAGE 4
LTC2637 PRODUCT SELECTION GUIDE PART MARKING* POWER-ON RESET TO CODE POWER-ON REFERENCE MODE RESOLUTION VCC PART NUMBER DFN MSOP VFS WITH INTERNAL REFERENCE MAXIMUM INL LTC2637-LMI12 7LMI2 7LMI12 2.5V • (4095/4096) Mid-Scale Internal 12-Bit 2.7V to 5.5V LTC2637-LMI10 7LMI1 7LMI10 2.5V • (1023/1024) Mid-Scale Internal 10-Bit 2.7V to 5.5V ±1LSB LTC2637-LMI8 7LMI8 37LMI8 2.5V • (255/256) Mid-Scale Internal 8-Bit 2.7V to 5.5V ±0.5LSB LTC2637-LMX12 7LMX2 7LMX12 2.
PAGE 5
LTC2637 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. LTC2637-LMI12/ LTC2637-LMI10/ LTC2637-LMI8/ LTC2637-LMX12/ LTC2637-LMX10/ LTC2637-LMX8/ LTC2637-LZ12/ LTC2637-LZ10/ LTC2637-LZ8 (VFS = 2.
PAGE 6
LTC2637 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. LTC2637-LMI12/ LTC2637-LMI10/ LTC2637-LMI8/ LTC2637-LMX12/ LTC2637-LMX10/ LTC2637-LMX8/ LTC2637-LZ12/ LTC2637-LZ10/ LTC2637-LZ8 (VFS = 2.
PAGE 7
LTC2637 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. LTC2637-LMI12/ LTC2637-LMI10/ LTC2637-LMI8/ LTC2637-LMX12/ LTC2637-LMX10/ LTC2637-LMX8/ LTC2637-LZ12/ LTC2637-LZ10/ LTC2637-LZ8 (VFS = 2.5V) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS AC Performance tS Settling Time VCC = 3V (Note 9) ±0.39% (±1LSB at 8 Bits) ±0.
PAGE 8
LTC2637 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. LTC2637-HMI12/ LTC2637-HMI10/ LTC2637-HMI8/ LTC2637-HMX12/ LTC2637-HMX10/ LTC2637-HMX8/ LTC2637-HZ12/ LTC2637-HZ10/ LTC2637-HZ8 (VFS =4.
PAGE 9
LTC2637 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. LTC2637-HMI12/ LTC2637-HMI10/ LTC2637-HMI8/ LTC2637-HMX12/ LTC2637-HMX10/ LTC2637-HMX8/ LTC2637-HZ12/ LTC2637-HZ10/ LTC2637-HZ8 (VFS =4.096V) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Output Impedance 0.
PAGE 10
LTC2637 TIMING CHARACTERISTICS The l denotes speciﬁcations that apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VCC =4.5V to 5.5V. (See Figure 1) (Note 13). LTC2637-HMI12/ LTC2637-HMI10/ LTC2637-HMI8/ LTC2637-HMX12/ LTC2637-HMX10/ LTC2637-HMX8/ LTC2637-HZ12/ LTC2637-HZ10/ LTC2637-HZ8 (VFS =4.096V) SYMBOL PARAMETER fSCL SCL Clock Frequency CONDITIONS l MIN 0 TYP MAX UNITS 400 kHz tHD(STA) Hold Time (Repeated) Start Condition l 0.
PAGE 11
LTC2637 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. LTC2637-L12 (Internal Reference, VFS = 2.5V) Integral Nonlinearity (INL) Differential Nonlinearity (DNL) 1.0 1.0 VCC = 3V VCC = 3V 0.5 DNL (LSB) INL (LSB) 0.5 0 –0.5 –1.0 0 –0.5 1024 0 2048 CODE 3072 –1.0 4095 1024 0 3072 2048 CODE 4095 2637 G01 INL vs Temperature Reference Output Voltage vs Temperature DNL vs Temperature 1.0 1.0 VCC = 3V INL (POS) VCC = 3V 0.5 INL (NEG) –0.5 1.
PAGE 12
LTC2637 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. LTC2637-H12 (Internal Reference, VFS = 4.096V) Integral Nonlinearity (INL) Differential Nonlinearity (DNL) 1.0 1.0 VCC = 5V VCC = 5V 0.5 DNL (LSB) INL (LSB) 0.5 0 –0.5 –1.0 0 –0.5 1024 0 2048 CODE 3072 –1.0 4095 0 1024 3072 2048 CODE 4095 2637 G08 INL vs Temperature Reference Output Voltage vs Temperature DNL vs Temperature 1.0 2.068 1.0 VCC = 5V INL (POS) 2.058 INL (NEG) –0.
PAGE 13
LTC2637 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. LTC2637-10 Integral Nonlinearity (INL) Differential Nonlinearity (DNL) 1.0 1.0 VCC = 3V VFS = 2.5V INTERNAL REF. VCC = 3V VFS = 2.5V INTERNAL REF. 0.5 DNL (LSB) INL (LSB) 0.5 0 –0.5 –1.0 0 –0.5 256 0 768 512 CODE –1.0 1023 256 0 768 512 CODE 2637 G15 1023 2637 G16 LTC2637-8 Integral Nonlinearity (INL) Differential Nonlinearity (DNL) 0.50 0.50 VCC = 3V VFS = 2.5V INTERNAL REF. VCC = 3V VFS = 2.
PAGE 14
LTC2637 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. LTC2637 Large-Signal Response Mid-Scale Glitch Impulse Power-On Reset Glitch LTC2637-L 9TH CLOCK OF 3RD DATA BYTE SCL 5V/DIV VCC 2V/DIV VOUT 0.5V/DIV LTC2637-H12 VCC = 5V, 3nV•s TYP VOUT 5mV/DIV ZERO-SCALE VOUT 5mV/DIV LTC2637-L12 VCC = 3V, 2.
PAGE 15
LTC2637 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. LTC2637 Gain Error vs. Temperature Noise Voltage vs. Frequency 500 NOISE VOLTAGE (nV/√Hz) GAIN ERROR (%FSR) 1.0 0.5 0 –0.5 400 VCC = 5V CODE = MID-SCALE INTERNAL REF. 300 LTC2637-H 200 LTC2637-L 100 –1.0 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 0 100 1k 100k 10k FREQUENCY (Hz) 2637 G31 2637 G32 0.1Hz to 10Hz Voltage Noise Gain Error vs Reference Input 1.0 VCC = 5V, VFS = 2.
PAGE 16
LTC2637 PIN FUNCTIONS (DFN/MSOP) VCC (Pin 1/Pin 1): Supply Voltage Input. 2.7V ≤ VCC ≤ 5.5V (LTC2637-L) or 4.5V ≤ VCC ≤ 5.5V (LTC2637-H). Bypass to GND with a 0.1μF capacitor. VOUTA to VOUTH (Pins 2–5, 10–13/Pins 2–5, 12–15): DAC Analog Voltage Outputs. CAO (Pin 6/Pin 7): Chip Address Bit 0. Tie this pin to VCC, GND or leave it ﬂoating to select an I2C slave address for the part (See Tables 1 and 2). SCL (Pin 7/Pin 8): Serial Clock Input Pin.
PAGE 17
LTC2637 BLOCK DIAGRAM SWITCH INTERNAL REFERENCE REF VREF GND REGISTER REGISTER DAC A REGISTER VOUTA REGISTER VCC DAC H REGISTER REGISTER DAC B REGISTER REGISTER VOUTB DAC G REGISTER REGISTER DAC C REGISTER REGISTER VOUTC DAC F VOUTF VREF REGISTER REGISTER DAC D REGISTER VOUTD REGISTER VREF DAC E VOUTE POWER-ON RESET CAO (CA2) VOUTG VREF VREF (CA1) VOUTH VREF VREF DECODE I2C ADDRESS DECODE SCL SDA I2C INTERFACE 2637 BD ( ) MSOP PACKAGE ONLY TEST CIRCUITS Tes
PAGE 18
SCL START A5 2 A6 1 3 A4 4 A3 5 A2 SLAVE ADDRESS 6 A1 tf 7 A0 SCL SDA tHD(STA) tHD(DAT) tr tHIGH tSU(DAT) tf tSU(STA) 8 W 9 ACK 1 C3 2 C2 3 C1 5 A3 6 A2 7 A1 8 A0 9 ACK 1 2 3 4 5 2ND DATA BYTE tHD(STA) Figure 2. Typical LTC2637 Write Transaction 4 C0 1ST DATA BYTE Sr Figure 1.
PAGE 19
LTC2637 OPERATION The LTC2637 is a family of octal voltage output DACs in 14-lead DFN and 16-lead MSOP packages. Each DAC can operate rail-to-rail using an external reference, or with its full-scale voltage set by an integrated reference. Eighteen combinations of accuracy (12-, 10-, and 8-bit), power-on reset value (zero-scale, mid-scale in internal reference mode, or mid-scale in external reference mode), and fullscale voltage (2.5V or 4.096V) are available.
PAGE 20
LTC2637 OPERATION Acknowledge The Acknowledge (ACK) signal is used for handshaking between the master and the slave. An ACK (active LOW) generated by the slave lets the master know that the latest byte of information was properly received. The ACK related clock pulse is generated by the master. The master releases the SDA line (HIGH) during the ACK clock pulse.
PAGE 21
LTC2637 OPERATION Write Word Protocol The master initiates communication with the LTC2637 with a START condition and a 7-bit slave address followed by the Write bit (W) = 0. The LTC2637 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 or CA2) or the global address. The master then transmits three bytes of data.
PAGE 22
LTC2637 OPERATION Write Word Protocol for LTC2637 S SLAVE ADDRESS W ACK 1ST DATA BYTE ACK 2ND DATA BYTE ACK 3RD DATA BYTE ACK INPUT WORD Input Word (LTC2637-12) C3 C2 C1 C0 A3 A2 P A1 A1 D11 D10 D9 1ST DATA BYTE D8 D7 D6 D5 D4 D3 D2 D1 2ND DATA BYTE D0 X X X X X X X X 3RD DATA BYTE Input Word (LTC2637-10) C3 C2 C1 C0 A3 A2 A1 A0 D9 D8 1ST DATA BYTE D7 D6 D5 D4 D3 D2 D1 D0 X 2ND DATA BYTE X X X 3RD DATA BYTE Input Word (LTC2637-8) C3 C2 C1 C0 A3 A2 1ST D
PAGE 23
LTC2637 OPERATION command 0111b. In addition, all the DAC channels and the integrated reference together can be put into powerdown mode using Power Down Chip command 0101b. When the integrated reference and all DAC channels are in power-down mode, the REF pin becomes high impedance (typically > 1GΩ). For all power-down commands the 16-bit data word is ignored. Normal operation resumes after executing any command that includes a DAC update, (as shown in Table 1).
PAGE 24
LTC2637 OPERATION analog section of the ground plane. The resistance from the LTC2637 GND pin to the ground plane should be as low as possible. Resistance here will add directly to the effective DC output impedance of the device (typically 0.1Ω). Note that the LTC2637 is no more susceptible to this effect than any other parts of this type; on the contrary, it allows layout-based performance improvements to shine rather than limiting attainable performance with excessive internal resistance.
PAGE 25
LTC2637 TYPICAL APPLICATION LTC2637 DACs Adjust LTC2755-16 Offsets, Ampliﬁed with LT1991 PGA to ±5V 5V 15 15V 0.1μF VDD LTC2755 0.1μF 8 7 + 5 4 – IOUT1A 59 2 – IOUT2A 2 3 + DAC A 6 0.1μF 8 1/2 LT1469 OUTA 4 0.1μF DAC D 5V 11 REF 0.1μF –15V –15V + – OUTD 15V 1 RVOSA 58 62 REFA + – 0.1μF 63 RCOM1 1/2 LT1469 LTC6240 15V RFBA 60 61 ROFSA 64 RIN1 2 VCC 1 0.1μF LTC2637MS-LMI12 DAC A DAC H DAC B DAC G 15 LT1634-1.25 LT1634-1.25 3 30k 1 P1 2 P3 3 P9 0.
PAGE 26
LTC2637 PACKAGE DESCRIPTION DE Package 14-Lead (4mm × 3mm) Plastic DFN (Reference LTC DWG # 05-08-1708 Rev B) R = 0.115 TYP 4.00 p 0.10 (2 SIDES) R = 0.05 TYP 0.70 p 0.05 3.30 p 0.05 3.60 p 0.05 2.20 p 0.05 14 3.30 p 0.10 3.00 p 0.10 (2 SIDES) 1.70 p 0.05 0.40 p 0.10 8 1.70 p 0.10 PIN 1 NOTCH R = 0.20 OR 0.35 s 45o CHAMFER PIN 1 PACKAGE TOP MARK OUTLINE (SEE NOTE 6) (DE14) DFN 0806 REV B 7 0.25 p 0.05 0.50 BSC 1 0.25 p 0.05 0.50 BSC 0.75 p 0.05 0.200 REF 3.00 REF 3.00 REF 0.00 – 0.
PAGE 27
LTC2637 REVISION HISTORY REV DATE DESCRIPTION PAGE NUMBER A 10/09 Update LTC2637-12 Maximum Limits B 06/10 5, 6, 8 Added details to Note 3 10 Revised Typical Application circuit 25 Added Typical Application drawing and revised Related Parts 28 2637fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use.
PAGE 28
LTC2637 TYPICAL APPLICATION LTC2637 DACs Adjust LTC2755-16 Offsets, Ampliﬁed with LT1991 PGA to ±5V 5V 15 15V 0.1μF VDD LTC2755 0.1μF 8 7 + IOUT1A 59 5 4 – 2 DAC A IOUT2A 2 6 – 8 0.1μF 1/2 LT1469 3 + 15V 1 OUTA 5V 4 11 0.1μF RVOSA 58 62 REFA + – 0.1μF 63 RCOM1 1/2 LT1469 LTC6240 15V RFBA 60 61 ROFSA 64 RIN1 0.1μF –15V –15V + – OUTD DAC D REF 2 VCC 1 0.1μF LTC2637MS-LMI12 DAC A DAC H DAC B DAC G 15 LT1634-1.25 LT1634-1.25 3 30k 1 P1 2 P3 3 P9 0.