LINEAR TECHNOLOGY LTC2970, LTC2970-1 Technical data

FEATURES

LTC2970/LTC2970-1

Dual I2C Power

Supply Monitor and

Margining Controller

U

DESCRIPTIO

■

Less Than ±0.5% Total Unadjusted Error 14-Bit ΔΣ

ADC with On-Chip Reference

■

Dual, 8-Bit IDACs with 1x Voltage Buffers

■

Linear, Voltage Servo Adjusts Supply Voltages by

Ramping IDAC Outputs Up/Down

■

I2C™ Bus Interface (SMBus Compatible)

■

Extensive, User Conﬁ gurable Fault Monitoring

■

On-Chip Temperature Sensor

■

Available in 24-Lead 4mm × 5mm QFN Package

U

APPLICATIO S

■

Dual Power Supply Voltage Servo

■

Monitoring Supply Voltage and Current

■

Programmable Power Supplies

■

Programmable Reference

The LTC®2970 is a dual power supply monitor and

2

margining controller with an SMBus compatible I

C bus

interface. A low-drift, on-chip reference and 14-bit ΔΣ A/D converter allow precise measurements of supply voltages, load currents or internal die temperature. Fault manage-

⎯A⎯L⎯E⎯R⎯

ment allows

T to be asserted for conﬁ gurable over and under voltage fault conditions. Two voltage buffered, 8-bit IDACs allow highly accurate programming of DC/DC converter output voltages. The IDACs can be conﬁ gured to automatically servo the power supplies to the desired voltages using the ADC. The LTC2970-1 adds a tracking feature that can be used to turn multiple power supplies on or off in a controlled manner.

The bus address is set to 1 of 9 possible combinations by pin strapping the ASEL0 and ASEL1 pins. The LTC2970/ LTC2970-1 are packaged in the 24-lead, 4mm × 5mm QFN package.

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

U

TYPICAL APPLICATIO

Dual Power Supply Monitor and Controller (One of Two Channels Shown)

8V TO 15V

12V

IN

V

IN

DC/DC

CONVERTER

RUN/SS

SGND

GND

OUT

1/2 LTC2970

I+

I–

FB

LOAD

V

IN0_BM

V

IN0_BP

V

OUT0

V

IN0_AP

I

OUT0

V

IN0_AM

GND

ASEL0 ASEL1

V

GPIO_CFG

ALERT

SCL

SDA

GPIO_0

REF

ADC Total Unadjusted Error

vs Temperature

0.50

0.1μF

DD

0.1μF

2

C BUS

I

SMBUS

()

COMPATIBLE

0.1μF

29701 TA01

15 PARTS MOUNTED ON PCB

0.25

0

ERROR (%)

–0.25

–0.50

–25 0 50

–50

25

TEMPERATURE (°C)

ADC VIN = 5V

75

29701 TA01b

100

29701fc

1

LTC2970/LTC2970-1

WW

W

U

ABSOLUTE AXI U RATI GS

(Notes 1 and 2)

Supply Voltages:

......................................................... –0.3V to 6V

V

DD

.................................................... –0.3V to 15V

12V

IN

Digital Input/Output Voltages:

ASEL0, ASEL1 ............................ –0.3V to V

SDA, SCL, GPIO_CFG,

⎯A⎯L⎯E⎯R⎯

T, GPIO_0, GPIO_1 .......................... –0.3V to 6V

Analog Voltages:

V

IN0_AP

V

IN0_BM

V

IN1_BP

I

OUT0

, I

, V

OUT1

IN0_AM

IN1_AP

IN1_BM

, V , V , V

IN0_BP IN1_AM

, V

OUT0

,

.............. –0.3V to 6V

OUT1

, REF ......................... –0.3V to V

RGND .................................................... –0.3V to 0.3V

Operating Temperature Range:

LTC2970C ................................................ 0°C to 70°C

LTC2970I ............................................. –40°C to 85°C

Storage Temperature Range ...................–65°C to 125°C

Lead Temperature (Soldering, 10 sec) .................. 300°C

+ 0.3V

DD

+ 0.3V

DD

PIN CONFIGURATION

TOP VIEW

RGND

REF

ASEL0

ASEL1

24 23 22 21 20

1

V

IN0_AP

V

2

IN0_AM

V

3

IN0_BP

4

V

IN0_BM

V

5

IN1_AP

6

V

IN1_AM

7

V

IN1_BP

24-LEAD (4mm × 5mm) PLASTIC QFN

T

EXPOSED PAD (PIN 25) IS GND MUST BE SOLDERED TO PCB

JMAX

25

8 9

10 11 12

IN

DD

V

OUT0VOUT1

12V

IN1_BM

V

UFD PACKAGE

= 125°C, θJA = 37°C/W

V

GPIO_CFG

19

SDA

18

SCL

17

ALERT

16

GPIO_0

15

GPIO_1

14

I

13

I

OUT0

OUT1

ORDER INFORMATION

LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE

LTC2970CUFD#PBF LTC2970CUFD#TRPBF 2970 24-Lead (4mm × 5mm) Plastic DFN 0°C to 70°C

LTC2970CUFD-1#PBF LTC2970CUFD-1#TRPBF 29701 24-Lead (4mm × 5mm) Plastic DFN 0°C to 70°C

LTC2970IUFD#PBF LTC2970IUFD#TRPBF 2970 24-Lead (4mm × 5mm) Plastic DFN –40°C to 85°C

LTC2970IUFD-1#PBF LTC2970IUFD-1#TRPBF 29701 24-Lead (4mm × 5mm) Plastic DFN –40°C to 85°C

Consult LTC Marketing for parts speciﬁ ed with wider operating temperature ranges. *The temperature grade is identiﬁ ed by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/

For more information on tape and reel speciﬁ cations, go to: http://www.linear.com/tapeandreel/

2

29701fc

LTC2970/LTC2970-1

The ● denotes the speciﬁ cations which apply over the full operating

ELECTRICAL CHARACTERISTICS

temperature range, otherwise speciﬁ cations are at T C

= 100nF and C

VDD

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Power-Supply Characteristics

I

V

V12

DD

LKO

DD

12VIN Supply Current V

VDD Supply Current VDD = 5V, V

VDD Undervoltage Lockout VDD Ramping-Down, V

V

DD

Supply Input Operating Range

Regulator Output Voltage 8V ≤ V

Regulator Output Voltage Temperature Coefﬁ cient

Regulator Output Voltage Load Regulation

Regulator Line Regulation 8V ≤ V

Regulator Output Short-Circuit Current V

V

12VIN

12VIN Supply Operating Range

Voltage Reference Characteristics

V

REF

Reference Output Voltage 1.229 V

Reference Voltage Temperature Coefﬁ cient

Reference Overdrive Voltage Input Range

ADC Characteristics

N_ADC Resolution N_ADC = 8.192V/16384 500 μV/LSB

TUE_ADC Total Unadjusted Error V

INL_ADC Integral Nonlinearity (Note 4)

DNL_ADC Differential Nonlinearity (Note 7)

V

IN_ADC

V

OS_ADC

Input Voltage Range

Offset Error

Offset Error Drift 0.19 μV/°C

GAIN_ADC Gain Error Full-Scale V

Gain Error Drift 3 ppm/°C

T

CONV_ADC

C

IN_ADC

F

IN_ADC

I

LEAK_ADC

Conversion Time 33.3 ms

Input Sampling Capacitance 3pF

Input Sampling Frequency 61.4 kHz

Input Leakage Current 0V < VIN < 6V

IDAC Output Current Characteristics

N_I

OUT

INL_I

OUT

DNL_I

I

FS-IOUT

I

DRIFT-IOUT

I

OS-IOUT

Resolution (Guaranteed Monotonic) 8 Bits

Integral Nonlinearity V

Differential Nonlinearity V

OUT

Full-Scale Output Current V

Output Current Drift DAC Code = 'hff 32 ppm/°C

Offset Current DAC Code = 'h00

= 100nF.

REF

Undervoltage Lockout Hysteresis 118 mV

= 25°C. V

A

= 12V, VDD Floating

12VIN

–1mA ≤ I

12VIN

= 12V, VDD = 0V

12VIN

= 3V, VIN = V

IN

< VDD – 1.5V

IOUTn

< VDD – 1.5V

IOUTn

< VDD – 1.5V, DAC Code = 'hff

IOUTn

12VIN

= V

12VIN

DD

≤ 15V, –1mA ≤ I

≤ 0 160 ppm/mA

VDD

≤ 15V, I

VDD

INn_xP

= 6V

IN

= 12V, VDD and REF pins ﬂ oating unless otherwise indicated,

●

12VIN

= V

VDD

DD

≤ 0

●

3.7 4.14 4.4 V

●

4.5 5.75 V

●

4.75 4.95 5.25 V

= 0mA 80 ppm/V

●

–5 –34 –63 mA

●

815V

●

11.5V

– V

INn_xM

(Note 3)

●

–4.5 2 4.5 LSB

●

06V

●

–1000 –316 1000 μV

●

–236 –255 –276 μA

●

4.24 7.5 mA

3.7 5 mA

10 ppm/°C

2 ppm/°C

±0.5 %

±0.5 LSB

±0.4 %

±0.1 μA

±1 LSB

±0.1 μA

29701fc

3

LTC2970/LTC2970-1

The ● denotes the speciﬁ cations which apply over the full operating

ELECTRICAL CHARACTERISTICS

temperature range, otherwise speciﬁ cations are at T

= 100nF and C

C

VDD

= 100nF.

REF

= 25°C. V

A

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

Voltage Buffered IDAC Output Characteristics

INL_V

DNL_V

V

OS-VOUT

V

OUT

Integral Nonlinearity R

Differential Nonlinearity R

OUT

Offset Voltage VOS = V

Output Voltage Drift No Load on V

Load Regulation 0.1V < V

Leakage Current V

Short-Circuit Current Low V

Short-Circuit Current High V

= 10kΩ, No Load on V

IOUTn

= 10kΩ, No Load on V

IOUTn

– V

OUTn

< VDD – 1.5V, I

OUTn

0.1V < V

OUTn

< VDD – 1.5V, I

OUTn

High-Z, 0V ≤ V

Shorted to GND

Shorted to V

Soft Connect Comparator Characteristics (CMP0, CMP1)

V

OS

Offset Voltage ±3 mV

Temperature Sensor Characteristics

TMP Gain 0.25 °C/LSB

Voltage Divider Characteristics

12V

IN

GAIN_12V

Gain

IN

Digital Inputs SCL, SDA, GPIO_CFG, GPIO_0, GPIO_1

V

IH

Input High Threshold Voltage SDA, SCL

GPIO_CFG, GPIO_0, GIPO_1

V

IL

Input Low Threshold Voltage SDA, SCL

GPIO_CFG, GPIO_0, GIPO_1

V

I

LEAK

C

HYST

IN

Input Hysteresis 0.08 V

Input Leakage Current 0V ≤ VIN ≤ 6V

Input Capacitance 10 pF

Three State Inputs ASEL[1:0]

V

IH_ASEL

V

IL_ASEL

I

IN,HL

I

IN,Z

Open Drain Outputs SDA, GPIO_CFG, GPIO_0, GPIO_1,

V

OL

I

OH

Input High Threshold Voltage

Input Low Threshold Voltage

High, Low Input Current ASEL[1:0] = 0, V

High Z Input Current

⎯A⎯L⎯E⎯R⎯

T

Output Low Voltage I

SINK

= 3mA

Input Leakage Current 0V ≤ VIN ≤ 6V

= 12V, VDD and REF pins ﬂ oating unless otherwise indicated,

12VIN

●

1.6 ±10 mV

, No Load on V

IOUTn

OUTn

(Note 5)

OUTn

0.17 μV/°C

Source = 1mA –57 ppm/mA

VOUTn

Sink = 1mA 100 ppm/mA

VOUTn

●

0.329 0.333 0.335 V/V

●

1.5 V

●

1.0 V

●

0.5 V

●

±2 μA

●

1 ±100 nA

VDD – 0.5 V

DD

OUTn

≤ V

DD

±1 LSB

–50 mA

50 mA

2.1 V

1.6 V

±1 μA

±20 μA

0.4 V

±1 μA

4

29701fc

LTC2970/LTC2970-1

The ● denotes the speciﬁ cations which apply over the full operating

ELECTRICAL CHARACTERISTICS

temperature range, otherwise speciﬁ cations are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

2

C Interface Timing Characteristics

I

f

SCL

t

LOW

t

HIGH

t

BUF

t

HD,STA

t

SU,STA

t

SU,STO

t

HD,DAT

t

SU,DAT

t

SP

t

SETUP_GPIO

t

HOLD_GPIO

t

OUT_GPIO

Internal Timers

t

TIMEOUT_SMB

t

SETUP_ADC

t

TIMEOUT_

SYNC

t

HOLD_TRACK

Serial Clock Frequency (Note 6)

Serial Clock Low Period (Note 6)

Serial Clock High Period (Note 6)

Bus Free Time Between Stop and Start (Note 6)

Start Condition Hold Time (Note 6)

Start Condition Setup Time (Note 6)

Stop Condition Setup Time (Note 6)

Data Hold Time (LTC2970 Receiving Data) Data Hold Time (LTC2970 Transmitting Data)

Data Setup Time (LTC2970 Receiving Data) (Note 6)

Pulse Width of Spike Suppressed (Note 6)

GPIO_0 and GPIO_1 Setup Time GPIO_0 and GPIO_1 input setup time

GPIO_0 and GPIO_1 Hold Time GPIO_0 and GPIO_1 input hold time

GPIO_0 and GPIO_1 Output Time GPIO_0 and GPIO_1 output delay after

Stuck BUS Timer The LTC2970 will release the I2C bus and

ADC Channel Setup Time After selecting a new ADC channel, the

Tracking SYNC Failure Timer LTC2970-1 Only: The LTC2970-1 will

Tracking IDAC Disconnect Delay LTC2970-1 Only: After the tracking

= 25°C.

A

(Note 6)

prior to the 26th rising SCL of an IO()

2

I

C read. These inputs must be valid and stable by this time to be returned in the IO() read result. (Note 6)

after the 26th rising SCL of an IO() I read. These inputs must be held until this amount of time has elapsed to be returned in the IO() read result. (Note 6)

the 35th rising SCL of an I

2

C write. These outputs will become high impedance or begin driving low by this time. (Note 6)

terminate the current command if the command is not completed before this amount of time has elapsed.

LTC2970 will wait this amount of time to allow the analog input to settle before beginning an ADC conversion.

abort a pending SYNC() command if a tracking command is not received before this amount of time has elapsed.

algorithm asserts CPIO_CFG low, the LTC2970-1 will delay disconnecting the IDACs from the power supply feedback nodes by this amount of time. Used while tracking power supplies on.

●

10 400 kHz

●

1.3 μs

●

0.6 μs

●

1.3 μs

●

600 ns

●

600 ns

●

600 ns

●

0

300 900

●

100 ns

●

2.5 μs

●

2

C

2.5 μs

●

98 ns

2.5 μs

ns ns

24 32 39 ms

304 μs

255 ms

32 ms

29701fc

5

LTC2970/LTC2970-1

The ● denotes the speciﬁ cations which apply over the full operating

ELECTRICAL CHARACTERISTICS

temperature range, otherwise speciﬁ cations are at T

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

t

SETUP_TRACK

t

DEC_TRACK

Tracking IDAC Disconnect Delay LTC2970-1 Only: After the tracking

Tracking IDAC Decrement Rate LTC2970-1 Only: The LTC2970-1 changes

= 25°C.

A

algorithm asserts CPIO_CFG high, the LTC2970-1 will wait this amount of time before starting to decrement Chn_a_ delay_track[9:0]. Used while tracking power supplies off.

Chn_a_delay_track[9:0] at this rate.

32 ms

88 μs/LSB

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 currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to ground unless otherwise speciﬁ ed.

Note 3: TUE (%) is deﬁ ned as:

%

INL V LSB V

+

+500

μ

V

IN

OS

•Gain Error

100

(• / )

TIMING DIAGRAM

The I2C Bus Speciﬁ cation

SDA

t

SU;DAT

t

f

SCL

t

f

t

LOW

t

r

Note 4: Integral nonlinearity (INL) is deﬁ ned as the deviation of a code from a straight line passing through the actual endpoints (0V and 6V) of the transfer curve. The deviation is measured from the center of the quantization band.

Note 5: Nonlinearity is deﬁ ned from the ﬁ rst code that is greater than or equal to the maximum offset speciﬁ cation to code 255 (full-scale).

Note 6: Maximum capacitive load, C clock risetime (t (20 + 0.1 • C

) and falltime (tf) are: (20 + 0.1 • CB)(ns) < tr < 300ns and

r

)(ns) < tf < 300ns. CB = capacitance of one bus line in pF.

B

SCL and SDA external pull-up voltage, V

, for SCL and SDA is 400pF. Data and

B

, is 3V < VIO < 5.5V.

IO

Note 7: This speciﬁ cation is guaranteed by design.

t

HD;STA

t

SP

t

r

BUF

6

START

CONDITION

t

HD;STA

t

HD;DAT

t

HIGH

t

SU;STA

REPEATED START

CONDITION

t

SU;STO

STOP

CONDITION

START

CONDITION

29701 TD

29701fc

0

UW

TYPICAL PERFOR A CE CHARACTERISTICS

ADC Total Unadjusted Error vs Temperature ADC INL ADC DNL

0.050

0.025

0

–0.025

–0.050

–0.075

ERROR (%)

–0.100

–0.125

–0.150

–0.175

BASED ON AVERAGE OF 15 PARTS ASSEMBLED ON 1/8" THICK PCB

3.3V

ADC VIN = 5V

0

–50

–25

25 10

TEMPERATURE (oC)

1V

1.8V

2.5V

50

75

29701 G01

2.5

2.0

1.5

1.0

0.5

ERROR (LSBs)

0

–0.5

–1.0

0

12

INPUT VOLTAGE (V)

46

35

LTC2970/LTC2970-1

1.00

0.75

0.50

0.25

0

–0.25

ERROR (LSBs)

–0.50

–0.75

–1.00

29701 G02

12 4

0

INPUT VOLTAGE (V)

3

5

6

29701 G03

ADC Zero Code Center Offset Voltage vs Temperature

–305

–310

–315

(MV)

–320

OS

V

–325

–330

–335

–50

–25

ADC Noise Histogram

10,000,000

1,000,000

NUMBER OF READINGS

VIN = 0V

100000

10,000

1000

100

10

02550

TEMPERATURE (oC)

75 100

29701 G04

ADC Rejection vs Frequency at V

IN

0

–10

–20

–30

–40

–50

–60

REJECTION (dB)

–70

–80

–90

–100

1

10

100

FREQUENCY AT VIN (Hz)

Voltage Buffered IDAC INL

0.50

CHANNELS 0 AND 1 SHOWN

= R

IOUT1

= 10k7

R

IOUT0

0.25

0

ERROR (LSBs)

–0.25

1000

10000

29701 G05

ADC Rejection vs Frequency at V

IN

0

–10

–20

–30

–40

–50

–60

REJECTION (dB)

–70

–80

–90

–100

5000

0

15000 20000

10000

FREQUENCY AT VIN (Hz)

Voltage Buffered IDAC DNL

0.50

CHANNELS 0 AND 1 SHOWN

= R

R

IOUT0

0.25

0

ERROR (LSBs)

–0.25

IOUT1

= 10k7

25000

30000

29701 G06

1

–1 0 2

–2

OUTPUT CODE (LSBs)

1

29701 G07

–0.50

50

0

100

DAC CODE

150

200

29701 G08

250

–0.50

50

0

100

DAC CODE

150

200

250

29701 G09

29701fc

7

LTC2970/LTC2970-1

0

UW

TYPICAL PERFOR A CE CHARACTERISTICS

IDAC Output Current vs Temperature

257.4

IDAC CODE = 'hff

= 13kΩ

R

IOUT

257.2

257.0

256.8

256.6

OUTPUT CURRENT (μA)

256.4

256.2

–50

02550

–25

TEMPERATURE (°C)

Voltage Buffered IDAC Load Regulation Sinking

0.35

V

= 0.1V

IOUT

0.30

0.25

0.20

0.15

0.10

OUTPUT VOLTAGE (V)

75 10

29701 G10

90oC

25oC

–45oC

V

Offset Voltage

OUTn

vs Temperature

1.620

IDAC CODE = 'h00

1.615

1.610

1.605

1.600

OFFSET VOLTAGE (mV)

1.595

1.590

–50

02550

–25

TEMPERATURE (oC)

Voltage Buffered IDAC Transient Response to 1LSB DAC Code Change

100k7 SERIES RESISTANCE ON V R

= 10k7

IOUT

CODE 'h7f

10mV PER DIVISION

75 100

29701 G11

OUTn

CODE 'h80

Voltage Buffered IDAC Load Regulation Sourcing

3.500

3.498

3.496

3.494

OUTPUT VOLTAGE (V)

3.492

V

= 3.5V

IOUTn

3.490 –2

0

–4

CURRENT (mA)

Voltage Buffered IDAC SoftConnect Transient Response

100k7 SERIES RESISTANCE ON V R

= 10k7

IOUT

CODE 'h80

HIGH-Z

10mV PER DIVISION

–6

CONNECTED

–8

OUTn

25oC

–45oC

90oC

–10

29701 G12

0.05

0

246 10

0

CURRENT (mA)

Voltage Buffered IDAC Transient Response During Transition from On State to High-Z State

100k7 SERIES RESISTANCE ON V R

= 10k7

IOUT

HIGH-Z

CONNECTED

10mV PER DIVISION

10Ms PER DIVISION

OUTn

8

5Ms PER DIVISION

Regulator Output Voltage

= 12V

= 0A

50 100

–25 0

25 75

TEMPERATURE (oC)

29701 G15

29701 G18

29701fc

29701 G13

29701 G16

1Ms PER DIVISION

Temperature Sensor Error vs Temperature

1.5

1.0

0.5

0

ERROR (oC)

–0.5

–1.0

–1.5

–50

02550

–25

TEMPERATURE (oC)

29701 G14

75 100

29701 G17

V vs Temperature

4.945

V I

VDD

4.944

4.943

4.942

(V)

DD

V

4.941

4.940

4.939

4.938

–50

DD

12VIN

8

UW

TYPICAL PERFOR A CE CHARACTERISTICS

VDD Regulator Load Regulation

0

–100

–200

–300

(ppm)

–400

DD

ΔV

–500

–600

–700

V

= 12V

12VIN

–800

–1 –2 –4

0

CURRENT (mA)

–45°C

25°C90°C

–3

29701 G19

(ppm)

DD

–100

ΔV

–200

–300

–400

–500

–5

Regulator Line Regulation

V

DD

400

NO LOAD ON V

300

200

100

0

25°C

8

–45°C

9

90°C

DD

10 15

10

V

12VIN

(V)

12

13 14

UUU

PI FU CTIO S

LTC2970/LTC2970-1

VDD Regulator Short-Circuit Current vs Temperature

–25

V

= 12V

12VIN

= 0V

V

DD

–30

–35

SHORT-CIRCUIT CURRENT (mA)

–40

–50

–25 0 25 50

TEMPERATURE (°C)

29701 G20

75 100

29701 G21

V

(Pin 1): Positive CH0_A ADC Multiplexer Input.

IN0_AP

The output of the differential, 7:1 multiplexer connects to the input of the ADC. CH0_A can be conﬁ gured to servo IDAC0.

V

(Pin 2): Negative CH0_A ADC Multiplexer Input.

IN0_AM

The output of the differential, 7:1 multiplexer connects to the input of the ADC. CH0_A can be conﬁ gured to servo IDAC0.

V

(Pin 3): Positive CH0_B ADC Multiplexer Input. The

IN0_BP

output of the differential, 7:1 multiplexer connects to the input of the ADC. CH0_B is a voltage monitor input only.

V

(Pin 4): Negative CH0_B ADC Multiplexer Input.

IN0_BM

The output of the differential, 7:1 multiplexer connects to the input of the ADC. CH0_B is a voltage monitor input only.

V

(Pin 5): Positive CH1_A ADC Multiplexer Input.

IN1_AP

The output of the differential, 7:1 multiplexer connects to the input of the ADC. CH1_A can be conﬁ gured to servo IDAC1.

V

(Pin 6): Negative CH1_A ADC Multiplexer Input.

IN1_AM

The output of the differential, 7:1 multiplexer connects to the input of the ADC. CH1_A can be conﬁ gured to servo IDAC1.

V

(Pin 7): Positive CH1_B ADC Multiplexer Input. The

IN1_BP

output of the differential, 7:1 multiplexer connects to the input of the ADC. CH1_B is a voltage monitor input only.

V

(Pin 8): Negative CH1_B ADC Multiplexer Input.

IN1_BM

The output of the differential, 7:1 multiplexer connects to the input of the ADC. CH1_B is a voltage monitor input only.

(Pin 9): VDD Power Supply, Voltage Monitor Input,

V

DD

and Internal 5V Regulator Output. The supply input range is 4.5V to 5.75V. The V to the ADC through an internal mux. Bypass the V to device ground with a 100nF capacitor (C input voltage supply is available, ﬂ oat the V power the LTC2970 from the 12V

(Pin 10): 12V Power Supply and Voltage Monitor

12V

IN

Input. An internal regulator generates 5V from 12V input range for 12V

pin voltage can be connected

DD

). If no 5V

VDD

pin and

DD

pin.

IN

. The

IN

is 8V to 15V. Bypass this pin with a

IN

100nF capacitor. The regulator’s output is connected to the

pin. The 12VIN pin voltage can also be monitored by

V

DD

the ADC through a 3:1 attenuator and the internal mux. If no 12V supply input is available, tie the 12V

to the VDD

IN

pin and operate from 4.5V to 5.75V.

(Pin 11): CH0 Voltage Output. Buffered version of

V

OUT0

IDAC0 output voltage.

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9

LTC2970/LTC2970-1

UUU

PI FU CTIO S

V

(Pin 12): CH1 Voltage Output. Buffered version of

OUT1

IDAC1 output voltage.

(Pin 13): IDAC1 Current Output. Connect a resistor

I

OUT1

between this pin and the point-of-load ground for channel

1. The IDAC sources between 0 and 255μA.

(Pin 14): IDAC0 Current Output. Connect a resistor

I

OUT0

between this pin and the point-of-load ground for channel

0. The IDAC sources between 0 and 255μA.

GPIO_1 (Pin 15): General Purpose Input or Open Drain Digital Output. GPIO_1 can be conﬁ gured as the IDAC Fault or Faults output, a digital input, or an open-drain digital output.

GPIO_0 (Pin 16): General Purpose Input or Open Drain Digital Output. GPIO_0 can be conﬁ gured as the voltage monitor power-good or power-good bar output, a digital input, or a programmable open-drain output. Power good is the NOR of all instantaneous OV and UV faults; it does not include IDAC faults.

⎯A⎯L⎯E⎯R⎯

T (Pin 17): Open Drain Digital Output. Connect the

⎯A⎯L⎯E⎯R⎯

SMBALERT signal to this pin. either IDAC0 or IDAC1 rails out (optional), or when one of the monitored voltages ventures outside its UV and OV thresholds (also optional).

SCL (Pin 18): Serial Bus Clock Input.

T is asserted low when

SDA (Pin 19): Serial Bus Data Input and Output.

GPIO_CFG (Pin 20): GPIO Conﬁ guration Digital Input and

Open Drain Output. Pulling GPIO_CFG high will cause the GPIO_0 and GPIO_1 open-drain outputs to automatically assert low after a power-on reset. If GPIO_CFG is pulled low, then GPIO_0 and GPIO_1 do not assert low after power-up.

ASEL1 (Pin 21): Slave Address Select Bit 1. Tie this pin to the V location (see Table 2).

ASEL0 (Pin 22): Slave Address Select Bit 0. Tie this pin to the V location (see Table 2).

REF (Pin 23): Internal Reference Output or ADC Reference Overdrive Input. The voltage at this pin determines the full-scale input voltage of the delta-sigma ADC (V

SCALE

decouples the reference output from this pin. Bypass this pin to RGND with a 100nF capacitor (C

RGND (Pin 24): Reference Ground. Connect to device ground.

GND (Pin 25): Device Ground. Must be soldered to ground.

pin, ground, or ﬂ oat in order to select the address

DD

pin, ground, or ﬂ oat in order to select the address

DD

= 6.65 • V

, typically). An internal 3.5k resistor

REF

).

REF

FULL-

10

29701fc

BLOCK DIAGRA

LTC2970/LTC2970-1

W

IN0_AP

IN0_AM

IN0_BP

IN0_BM

IN1_AP

IN1_AM

IN1_BP

IN1_BM

1012V

IN

9V

DD

25GND

2R

R

12V

P

12V

M

V

DDP

V

DDM

5V REGULATOR

V

OUT

IN

IDAC0 8 BITS

V

DD

+

V

DD

VBUF0

0μA TO 255μA

+

CMP0

–

14 I

11 V

OUT0

–

TEMP

SENSOR

1V

2V

3V

4V

5V

6V

7V

8V

23REF

24RGND

18SCL

19SDA

(400kHz, SMBUS COMPATIBLE)

22ASEL0

21ASEL1

16GPIO_0

DAC SOFT CONNECT FUNCTION

15GPIO_1

17ALERT

20GPIO_CFG

MANAGE FAULT REPORTING

TRACKING CONTROL (LT2970-1)

TSNSP

TSNSM

CH0_AP

CH0_AM

CH0_BP

CH0_BM

CH1_AP

CH1_AM

CH1_BP

CH1_BM

7:1 MUX

I2C BUS INTERFACE

SERVO CONTROLLER

SERVO FUNCTION

MONITOR FUNCTION

WATCH DOG

POR

+

DELTA-SIGMA

–

6.65X (TYP)

OSCILLATOR

14-BIT

A/D

POR

ADC

CLOCKS

3.5k

7

2

UVLO

V

DD

REFERENCE

1.229V (TYP)

20Ω

CLOCK

GENERATION

IDAC1 8 BITS

+

VBUF1

–

RAM

ADC_Results MONITOR LIMITS SERVO TARGETS

REGISTERS

I/O CONFIGURATION IDAC0 IDAC1 ADC MONITOR FAULT ENABLE INSTANTANEOUS FAULTS LATCHED FAULTS

0μA TO 255μA

+

CMP1

–

13 I

OUT1

12 V

OUT1

18

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11

LINEAR TECHNOLOGY LTC2970, LTC2970-1 Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual