Linear Technology LTC1275BCS, LTC1275BCN, LTC1275ACS, LTC1275ACN, LTC1273ACS Datasheet

LTC1273

LTC1275/LTC1276

12-Bit, 300ksps Sampling

A/D Converters with Reference

FEATURES

■Single Supply 5V or ±5V Operation

■300ksps Sample Rate

■75mW (Typ) Power Dissipation

■On-Chip 25ppm/°C Reference

■Internal Synchronized Clock; No Clock Required

■High Impedance Analog Input

■70dB S/(N + D) and 77dB THD at Nyquist

■±1/2LSB INL and ±3/4LSB DNL Max (A Grade)

■ESD Protected On All Pins

■24-Pin Narrow DIP and SOL Packages

■Variety of Input Ranges:

0V to 5V (LTC1273)

±2.5V (LTC1275)

±5V (LTC1276)

APPLICATIOUS

■High Speed Data Acquisition

■Digital Signal Processing

■Multiplexed Data Acquisition Systems

■Audio and Telecom Processing

■Spectrum Analysis

DESCRIPTIOU

The LTC1273/LTC1275/LTC1276 are 300ksps, sampling 12-bit A/D converters that draw only 75mW from single 5V or ±5V supplies. These easy-to-use devices come complete with 600ns sample-and-holds, precision references and internally trimmed clocks. Unipolar and bipolar conversion modes provide flexibility for various applications. They are built with LTBiCMOSTM switched capacitor technology.

These devices have 25ppm/°C (max) internal references. The LTC1273 converts 0V to 5V unipolar inputs from a single 5V supply. The LTC1275/LTC1276 convert ±2.5V and ±5V respectively from ±5V supplies. Maximum DC specifications include ±1/2LSB INL, ±3/4LSB DNL and 25ppm/°C full scale drift over temperature. Outstanding AC performance includes 70dB S/(N + D) and 77dB THD at the Nyquist input frequency of 150kHz.

The internal clock is trimmed for 2.7μs maximum conversion time. The clock automatically synchronizes to each sample command eliminating problems with asynchronous clock noise found in competitive devices. A high speed parallel interface eases connections to FIFOs, DSPs and microprocessors.

LTBiCMOSTM is a trademark of Linear Technology Corporation

TYPICAL APPLICATIOU

Single 5V Supply, 300ksps, 12-Bit Sampling A/D Converter		Effective Bits and Signal to (Noise + Distortion)
LTC1273	5V	vs Input Frequency

		ANALOG INPUT	1	AIN	VDD	24				12			74
2.42V							+			11			68
		(0V TO 5V)	2			23		0.1μF
VREF		+	3	VREF	NC	22	10μF			10	NYQUIST		62
OUTPUT				AGND	BUSY
	10μF	0.1μF	4			21				9	FREQUENCY		56
				D11	CS
							μP CONTROL		BITS	8			50	S/(N
			5	D10	RD	20	LINES			7
			6	D9	HBEN	19			EFFECTIVE	6				(dB)D) +
			8	D7	NC	17
			7	D8	NC	18				5
			9	D6	D0/8	16				4
										3
		8- OR 12-BIT	10	D5	D1/9	15
										2
		PARALLEL BUS	11	D4	D2/10	14
										1	fSAMPLE = 300kHz
			12	DGND	D3/11	13
										0
											100k	1M	2M
										10k
											INPUT FREQUENCY (Hz)
												LTC1273/75/76 • TA02
							LTC1273/75/76 • TA01

1

LTC1273

LTC1275/LTC1276

ABSOLUTE

WAXIWUW

RATI GS	(Notes 1 and 2)
U

Supply Voltage (VDD) ..............................................		12V	Digital Output Voltage (Note 3)
Negative Supply Voltage (VSS)			LTC1273 ....................................	– 0.3V to VDD + 0.3V
LTC1275/LTC1276..................................		– 6V to GND	LTC1275/LTC1276 ..............	VSS – 0.3V to VDD + 0.3V
Total Supply Voltage (VDD to VSS)		12V	Power Dissipation .............................................		500mW
LTC1275/LTC1276...............................................			Operating Temperature Range
Analog Input Voltage (Note 3)			LTC1273AC, LTC1273BC, LTC1275AC		0°C to 70°C
LTC1273 ....................................		– 0.3V to VDD + 0.3V	LTC1275BC, LTC1276AC, LTC1276BC
LTC1275/LTC1276..............	VSS – 0.3V to VDD + 0.3V		Storage Temperature Range ................		– 65°C to 150°C
Digital Input Voltage (Note 4)			Lead Temperature (Soldering, 10 sec).................		300°C
LTC1273 ................................................		– 0.3V to 12V
LTC1275/LTC1276.........................		VSS – 0.3V to 12V

PACKAGE/ORDER IUFORWATIOU

			TOP VIEW
AIN					VDD
		1		24
VREF					NC
		2		23
AGND		3		22		BUSY
D11		4		21		CS
D10		5		20		RD
D9		6		19	HBEN
D8		7		18	NC
D7		8		17	NC
D6
		9		16	D0/8
D5					D1/9
		10		15
D4
		11		14	D2/10
DGND					D3/11
		12		13

N PACKAGE	S PACKAGE
24-LEAD PLASTIC DIP	24-LEAD PLASTIC SOL

TJMAX = 110°C, θJA = 100°C/W (N)

TJMAX = 110°C, θJA = 130°C/W (S)

ORDER

PART NUMBER

LTC1273ACN

LTC1273BCN

LTC1273ACS

LTC1273BCS

(For MIL Grade:

Contact Factory)

			TOP VIEW
AIN					VDD
		1		24
VREF					VSS
		2		23
AGND		3		22		BUSY
D11		4		21		CS
D10		5		20		RD
D9		6		19	HBEN
D8		7		18	NC
D7		8		17	NC
D6
		9		16	D0/8
D5					D1/9
		10		15
D4
		11		14	D2/10
DGND					D3/11
		12		13

N PACKAGE	S PACKAGE
24-LEAD PLASTIC DIP	24-LEAD PLASTIC SOL

TJMAX = 110°C, θJA = 100°C/W (N)

TJMAX = 110°C, θJA = 130°C/W (S)

ORDER

PART NUMBER

LTC1275ACN

LTC1275BCN

LTC1275ACS

LTC1275BCS

LTC1276ACN

LTC1276BCN

LTC1276ACS

LTC1276BCS

(For MIL Grade:

Contact Factory)

CO	VERTER	CHARACTERISTICS			With Internal Reference (Notes 5 and 6)
U
					LTC1273A/LTC1275A/LTC1276A			LTC1273B/LTC1275B/LTC1276B
PARAMETER			CONDITIONS		MIN	TYP	MAX	MIN	TYP	MAX	UNITS
Resolution (No Missing Codes)				●	12			12			Bits
Integral Linearity Error			(Note 7)				±1/2			±1	LSB
			Commercial	●			±1/2			±1	LSB
			Military	●			±3/4			±1	LSB
Differential Linearity Error			Commercial	●			±3/4			±1	LSB
			Military	●			±1			±1	LSB
Offset Error			(Note 8)				±3			±4	LSB
				●			±4			±6	LSB
Full Scale Error							±10			±15	LSB
Full Scale Tempco			IOUT(REFERENCE) = 0	●		±5	±25		±10	±45	ppm/°C

2

LTC1273

LTC1275/LTC1276

DY	A		IC	ACCURACY	(Note 5)
U		W
							LTC1273A/LTC1275A/LTC1276A
							LTC1273B/LTC1275B/LTC1276B
SYMBOL		PARAMETER				CONDITIONS	MIN	TYP	MAX	UNITS
S/(N + D)		Signal-to-Noise Plus Distortion Ratio				50kHz/150kHz Input Signal		72/70		dB
THD		Total Harmonic Distortion				50kHz/150kHz Input Signal		– 83/– 74		dB
		Up to 5th Harmonic
		Peak Harmonic or Spurious Noise				50kHz/150kHz Input Signal		– 85/– 76		dB
IMD		Intermodulation Distortion				fIN1 = 29.37kHz, fIN2 = 32.446kHz		– 80		dB
		Full Power Bandwidth						4.5		MHz
		Full Linear Bandwidth (S/(N + D) ³ 68dB)						200		kHz

AUALOG I

U

PUT

(Note 5)

							LTC1273A/LTC1275A/LTC1276A
							LTC1273B/LTC1275B/LTC1276B
SYMBOL	PARAMETER	CONDITIONS					MIN	TYP	MAX	UNITS
VIN	Analog Input Range (Note 9)	4.95V			£ VDD £ 5.25V (LTC1273)	●		0 to 5		V
			4.75V		£ VDD £ 5.25V, – 5.25V £ VSS £ – 2.45V (LTC1275)	●		±2.5		V
			4.95V		£ VDD £ 5.25V, – 5.25V £ VSS £ – 4.95V (LTC1276)	●		±5		V
IIN	Analog Input Leakage Current								±1	mA
			CS	= High		●
CIN	Analog Input Capacitance		Between Conversions (Sample Mode)					50		pF
			During Conversions (Hold Mode)					5		pF
tACQ	Sample-and-Hold		Commercial			●			600	ns
	Acquisition Time		Military			●			1000	ns

IUTERUAL REFEREUCE CHARACTERISTICS (Note 5)

			LTC1273A/LTC1275A/LTC1276A			LTC1273B/LTC1275B/LTC1276B
PARAMETER	CONDITIONS		MIN	TYP	MAX	MIN	TYP	MAX	UNITS
VREF Output Voltage	IOUT = 0		2.400	2.420	2.440	2.400	2.420	2.440	V
VREF Output Tempco	IOUT = 0	●		±5	±25		±10	±45	ppm/°C
VREF Line Regulation	4.95V £ VDD £ 5.25V			0.01			0.01		LSB/V
	– 5.25V £ VSS £ – 4.95V			0.01			0.01		LSB/V
VREF Load Regulation	0V £ |IOUT| £ 1mA			2			2		LSB/mA

DIGITAL IUPUTS AUD DIGITAL OUTPUTS (Note 5)

				LTC1273A/LTC1275A/LTC1276A
				LTC1273B/LTC1275B/LTC1276B
SYMBOL	PARAMETER	CONDITIONS		MIN	TYP	MAX	UNITS
VIH	High Level Input Voltage	VDD = 5.25V	●	2.4			V
VIL	Low Level Input Voltage	VDD = 4.95V	●			0.8	V
IIN	Digital Input Current	VIN = 0V to VDD	●			±10	mA
CIN	Digital Input Capacitance				5		pF
VOH	High Level Output Voltage	VDD = 4.95V
		IO = – 10mA			4.7		V
		IO = – 200mA	●	4.0			V

3

LTC1273

LTC1275/LTC1276

DIGITAL IUPUTS AUD DIGITAL OUTPUTS (Note 5)

								LTC1273A/LTC1275A/LTC1276A
								LTC1273B/LTC1275B/LTC1276B
SYMBOL	PARAMETER	CONDITIONS						MIN	TYP	MAX	UNITS
VOL	Low Level Output Voltage	VDD = 4.95V
			IO = 160μA						0.05		V
			IO = 1.6mA				●		0.10	0.4	V
										±10	μA
IOZ	High Z Output Leakage D11-D0/8	VOUT = 0V to VDD,			CS	High	●
COZ	High Z Output Capacitance D11-D0/8			High (Note 9 )						15	pF
			CS				●
ISOURCE	Output Source Current	VOUT = 0V							– 10		mA
ISINK	Output Sink Current	VOUT = VDD							10		mA

POWER REQUIREWEUTS (Note 5)

				LTC1273A/LTC1275A/LTC1276A
				LTC1273B/LTC1275B/LTC1276B
SYMBOL	PARAMETER	CONDITIONS		MIN	TYP	MAX	UNITS
VDD	Positive Supply Voltage	LTC1273/LTC1276 (Notes 10, 11)		4.95		5.25	V
		LTC1275 (Note 10)		4.75		5.25	V
VSS	Negative Supply Voltage	LTC1275 (Note 10)		– 2.45		– 5.25	V
		LTC1276 (Notes 10, 11)		– 4.95		– 5.25	V
IDD	Positive Supply Current		●		15	25	mA
ISS	Negative Supply Current	LTC1275/LTC1276	●		0.065	0.200	mA
PD	Power Dissipation				75		mW

TIWIUG CHARACTERISTICS See Timing Characteristics Figures (Note 5)

LTC1273A/LTC1275A/LTC1276A

LTC1273B/LTC1275B/LTC1276B

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

fSAMPLE(MAX)

Maximum Sampling Frequency

(Note 10)

Commercial

●

300

kHz

Military

●

250

kHz

tCONV

Conversion Time

Commercial

●

2.7

μs

Military

●

3.0

μs

t1

to

Setup Time

0

ns

CS

RD

●

t2

to

Delay

CL = 50pF

80

190

ns

RD

BUSY

Commercial

●

230

ns

Military

●

270

ns

t3

Data Access Time After

↓

CL = 20pF

40

90

ns

RD

Commercial

●

110

ns

Military

●

120

ns

CL = 100pF

50

125

ns

Commercial

●

150

ns

Military

●

170

ns

t4

Pulse Width

t3

ns

RD

●

t5

CS

to

RD

Hold Time

●

0

ns

t6

Data Setup Time After

−

40

70

ns

BUSY

Commercial

●

90

ns

Military

●

100

ns

4

LTC1273

LTC1275/LTC1276

TIWIUG CHARACTERISTICS See Timing Characteristics Figures (Note 5)

LTC1273A/LTC1275A/LTC1276A

LTC1273B/LTC1275B/LTC1276B

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

t7

Bus Relinquish Time

20

30

75

ns

Commercial

●

20

85

ns

Military

●

20

90

ns

t8

HBEN to

Setup Time

0

ns

RD

●

t9

HBEN to

RD

Hold Time

●

0

ns

t10

Delay Between

Operations

40

ns

RD

●

t11

Delay Between Conversions

(Note 10)

500

ns

Commercial

●

600

ns

Military

●

1000

ns

t12

Aperture Delay of Sample-and-Hold

25

ns

The ● indicates specifications which apply over the full operating temperature range; all other limits and typicals TA = 25°C.

Note 1: Absolute maximum ratings are those values beyond which the life of a device may be impaired.

Note 2: All voltage values are with respect to ground with DGND and AGND wired together (unless otherwise noted).

Note 3: When these pin voltages are taken below VSS (ground for LTC1273) or above VDD, they will be clamped by internal diodes. This product can handle input currents greater than 60mA below VSS (ground for LTC1273) or above VDD without latch-up.

Note 4: When these pin voltages are taken below VSS (ground for LTC1273) they will be clamped by internal diodes. This product can handle input currents greater than 60mA below VSS (ground for LTC1273) without latch-up. These pins are not clamped to VDD.

Note 5: VDD = 5V (VSS = – 5V for LTC1275/LTC1276), 300kHz at 70°C and 250kHz at 125°C, tr = tf = 5ns unless otherwise specified.

Note 6: Linearity, offset and full scale specifications apply for unipolar and bipolar modes.

Note 7: Integral nonlinearity is defined as the deviation of a code from a straight line passing through the actual endpoints of the transfer curve. The deviation is measured from the center of the quantization band.

Note 8: Bipolar offset (LTC1275/LTC1276) is the different voltage measured from – 0.5LSB when the LTC1275/LTC1276 output code flickers between 0000 0000 0000 and 1111 1111 1111.

Note 9: Guaranteed by design, not subject to test. Note 10: Recommended operating conditions.

Note11: AIN must not exceed VDD or fall below VSS by more than 50mV for specified accuracy. Therefore the minimum supply voltage for the LTC1273 is +4.95V. The minimum supplies for the LTC1275 are +4.75V and – 2.45V and the minimum supplies for the LTC1276 are ±4.95V.

TIWIUG CHARACTERISTICS (Note 5)

Slow Memory Mode, Parallel Read Timing Diagram

ROM Mode, Parallel Read Timing Diagram

	CS			CS
	t1	t5	t1	t1	t5	t1	t5
	RD			RD	t4		t4
						t11
	t2		t10	t2
		tCONV	t11		tCONV	t2	tCONV
	BUSY			BUSY
			t7
	t3	t6		t3	t7	t3	t7

DATA

OLD DATA

NEW DATA

DATA

OLD DATA

NEW DATA

DB11 TO DB0

DB11 TO DB0

DB11 TO DB0

DB11 TO DB0

HOLD

t12

HOLD

t12

t12

TRACK

TRACK

LTC1273/75/76 • TA03

LTC1273/75/76 • TA04

5

LTC1273

LTC1275/LTC1276

TIWIUG CHARACTERISTICS (Note 5)

Slow Memory Mode, Two Byte Read Timing Diagram

HBEN
	t8			t9	t8	t9
CS
	t1			t5	t1	t5
RD						t4
	t2			t10	t11	t10
		tCONV
BUSY
	t3		t6	t7	t3	t7
DATA		OLD DATA		NEW DATA		NEW DATA
		DB7 TO DB0		DB7 TO DB0		DB11 TO DB8
HOLD	t12					t12
TRACK						LTC1273/75/76 • TA05

ROM Mode, Two Byte Read Timing Diagram

HBEN

t8

CS

t1

RD

t2

BUSY

t3

DATA

t12

HOLD

t9

t5

t4

tCONV

t7

OLD DATA

DB7 TO DB0

TRACK

t8

t1

t3

t9	t8		t9
t5	t1		t5
t4			t4
t11	t10	t2
t7		t3	t7
NEW DATA			NEW DATA
DB11 TO DB8			DB7 TO DB0
		t12

LTC1273/75/76 • TA06

6

LTC1273

LTC1275/LTC1276

TYPICAL PERFORWAUCE CHARACTERISTICS

			Integral Nonlinearity																														Differential Nonlinearity
	1.0																														1.0
(LSB)	0.5																													(LSB)	0.5
ERRORINL	0																													ERRORDNL	0
	–0.5																														–0.5
	–1.0																														–1.0
		0			512		1024 1536 2048 2560 3072 3584 4096																									0		512				1024 1536 2048 2560 3072 3584 4096
															CODE																														CODE
																					LTC1273/75/76 • TPC01																																	LTC1273/75/76 • TPC02
			ENOBs and S/(N + D)																																Signal-to-Noise Ratio (Without
			vs Input Frequency																																Harmonics) vs Input Frequency
	12																												74			80
	11																												68			70
NUMBEREFFECTIVEOF BITS	10																												62		NOISE-TO-SIGNALRATIO (dB)
																													(dB)D)+S/(N
	9																												56			60
	8																												50			50
	7
	6																															40
	5																															30
	4
																																20
	3
	2																															10
	1
				fSAMPLE = 300kHz																																fSAMPLE = 300kHz
	0																															0
													100k												1M			2M						1k									10k								100k											1M
	10k
								INPUT FREQUENCY (Hz)																																		INPUT FREQUENCY (Hz)
																				LTC1273/75/76 • TPC04																																			LTC1273/75/76 • TPC05

Supply Current vs Temperature

		25
	(mA)	20
	CURRENT	15
	SUPPLY	10
		5
		0

–50 –25 0 25 50 75 100 125 TEMPERATURE (°C)

LTC1273/75/76 • TPC03

Distortion vs Input Frequency

FUNDAMENTAL)

0

–10

f

SAMPLE = 300kHz

–20

THD

2nd HARMONIC

THE

–30

3rd

HARMONIC

–40

BELOW

–60

(dB

–50

–70

AMPLITUDE

–80

–90

–100

1k 10k 100k 1M 10M INPUT FREQUENCY (Hz)

LTC1273/75/76 • TPC06

Power Supply Feedthrough

(dB)

vs Ripple Frequency (LTC1273)

0

FEEDTHROUGH

–40

f

SAMPLE = 300kHz

–20

SUPPLY

VDD

–60

(VRIPPLE = 1mV)

POWEROF

–80

AMPLITUDE

–100

DGND

(VRIPPLE = 0.1V)

–120

1k

10k

100k

1M

RIPPLE FREQUENCY (Hz)

LTC1273/75/76 • TPC07

Power Supply Feedthrough

(dB)

vs Ripple Frequency (LTC1275/76)

0

FEEDTHROUGH

–40

f

SAMPLE = 300kHz

DGND

(V

RIPPLE

=

0.1V)

–20

VDD (VRIPPLE = 1mV)

SUPPLY

VSS (VRIPPLE = 10mV)

–60

POWEROF

–80

AMPLITUDE

–100

1k

10k

100k

1M

–120

RIPPLE FREQUENCY (Hz)

LTC1273/75/76 • TPC08

7

LTC1273

LTC1275/LTC1276

TYPICAL PERFORWAUCE CHARACTERISTICS

Intermodulation Distortion Plot

	0
							fSAMPLE = 300kHz
	–20						fIN1 = 29.37kHz
							fIN2 = 32.446kHz
(dB)	–40
AMPLITUDE	–80
	–60
	–100
	–120

0 20 40 60 80 100 120 140 160 FREQUENCY (kHz)

LTC1273/75/76 • F05

Acquisition Time

vs Source Impedance

		4500
		4000
	(ns)	3500
		3000
	TIME
		2500
	ACQUISITION
		2000
		1500

1000

500

0

10

100

1k

10k

RSOURCE (Ω)

LTC1273/75/76 • TPC10

SIGNAL/(NOISE + DISTORTION) (dB)

S/(N + D) vs Input Frequency and Amplitude

80 fSAMPLE = 300kHz

70

VIN = 0dB

60

VIN = –20dB

50

40

30

20
		VIN = –60dB
10
0

1k 10k 100k 1M 10M INPUT FREQUENCY (Hz)

LTC1273/75/76 • TPC11

Spurious Free Dynamic Range	Reference Voltage
vs Input Frequency	vs Load Current

SPURIOUS FREE DYNAMIC RANGE (dB)

0	fSAMPLE = 300kHz				2.435
–10
					2.430
–20
				(V)
–30
				VOLTAGE	2.425
–40
–50				REFERENCE	2.420
–60					2.415
–70
–80					2.410
–90
–100					2.405	–4	–3 –2 –1	0	1	2
10k	100k	1M	10M		–5
	INPUT FREQUENCY (Hz)						LOAD CURRENT (mA)

LTC1273/75/76 • TPC12	LTC1273/75/76 • TPC13

PIU FUUCTIOUS

AIN (Pin 1): Analog Input. 0V to 5V (LTC1273), ±2.5V (LTC1275) or ±5V (LTC1276).

VREF (Pin 2): +2.42V Reference Output. Bypass to AGND (10μF tantalum in parallel with 0.1μF ceramic).

AGND (Pin 3): Analog Ground.

D11-D4 (Pins 4 to 11): Three-State Data Outputs.

DGND (Pin 12): Digital Ground.

D3/11-D0/8 (Pins 13 to 16): Three-State Data Outputs.

NC (Pins 17 and 18): No Connection.

HBEN (Pin 19): High Byte Enable Input. This pin is used to multiplex the internal 12-bit conversion result into the lower bit outputs (D7-D0/8). See Table 1. HBEN also disables conversion start when HIGH.

RD (Pin 20): READ Input. This active low signal starts a conversion when CS and HBEN are low. RD also enables the output drivers when CS is low.

CS (Pin 21): The CHIP SELECT Input must be low for the ADC to recognize RD and HBEN inputs.

BUSY (Pin 22): The BUSY Output shows the converter status. It is low when a conversion is in progress.

8