NSC LM2612BTLX, LM2612BTL, LM2612BBLX, LM2612BBL, LM2612ATLX Datasheet

December 2002

LM2612BL

400mA Sub-miniature, Programmable, Step-Down DC-DC Converter for Ultra Low-Voltage Circuits

General Description

The LM2612 step-down DC-DC converter is optimized for powering ultra-low voltage circuits from a single Lithium-Ion cell. It provides up to 400mA (300mA for B grade), over an input voltage range of 2.8V to 5.5V. Pin programmable output voltages of 1.05V, 1.3V, 1.5V or 1.8V allow adjustment for MPU voltage options without board redesign or external feedback resistors.

The device has three pin-selectable modes for maximizing battery life in mobile phones and similar portable applications. Low-noise PWM mode offers 600kHz fixed-frequency operation to reduce interference in RF and data acquisition applications during full-power operation. In PWM mode, internal synchronous rectification provides high efficiency (91% typ. at 1.8VOUT). A SYNC input allows synchronizing the switching frequency in a range of 500kHz to 1MHz to avoid noise from intermodulation with system frequencies. Low-current hysteretic PFM mode reduces quiescent current to 160 µA (typ.) during system standby. Shutdown mode turns the device off and reduces battery consumption to 0.02µA (typ.). Additional features include soft start and current overload protection.

The LM2612 is available in a 10 pin micro SMD packge. This package uses National’s wafer level chip-scale micro SMD technology and offers the smallest possible size. Only three small external surface-mount components, an inductor and two ceramic capacitors are required.

Key Specifications

nOperates from a single LiION cell (2.8V to 5.5V)

nInternal synchronous rectification for high PWM mode efficiency

nPin programmable output voltage (1.05V, 1.3V, 1.5V and 1.8V)

n400mA maximum load capability (300mA for B grade)

n±2% PWM mode DC output voltage precision

n5mV typ PWM mode output voltage ripple

n160 µA typ PFM mode quiescent current

n0.02µA typ shutdown mode current

n600kHz PWM mode switching frequency

nSYNC input for PWM mode frequency synchronization from 500kHz to 1MHz

Features

nSub-miniature 10-pin micro SMD package

nOnly three tiny surface-mount external components required

nUses small ceramic capacitors

nInternal soft start

nCurrent overload protection

nNo external compensation required

nThermal shutdown protection

Applications

nMobile Phones

nHand-Held Radios

nBattery Powered Devices

Typical Application Circuit

20041802

Ultra for Converter DC-DC Down-Step Programmable, miniature,-Sub 400mA LM2612BL

Circuits Voltage-Low

© 2002 National Semiconductor Corporation

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LM2612BL

Connection Diagrams

micro SMD package

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TOP VIEW	BOTTOM VIEW

Ordering Information

Order Number		Package Type	NSC Package	Supplied As
			Marking(*)
10-Pin micro SMD
LM2612ABL		BLP106WB	XYTT IS41A	250 Units, Tape and Reel
LM2612BBL			XYTT IS41B	250 Units, Tape and Reel
		10-bump Wafer Level Chip Scale
LM2612ABLX			XYTT IS41A	3000 Units, Tape and Reel
		(micro SMD)
LM2612BBLX			XYTT IS41B	3000 Units, Tape and Reel
(*) XY - denotes the date code marking (2 digit) in production
TT - refers to die run/lot traceability for production
I - pin one indication
S - Product line designator
Note the Package Marking may change over the course of production time without notice

Order Number		Package Type	NSC Package	Supplied As
			Marking(*)
10-Pin micro SMD
LM2612ATL		TLP106WA	XYTT IS41A	250 Units, Tape and Reel
LM2612BTL			XYTT IS41B	250 Units, Tape and Reel
		10-bump Wafer Level Chip Scale
LM2612ATLX			XYTT IS41A	3000 Units, Tape and Reel
		(micro SMD)
LM2612BTLX			XYTT IS41B	3000 Units, Tape and Reel
(*) XY - denotes the date code marking (2 digit) in production
TT - refers to die run/lot traceability for production
I - pin one indication
S - Product line designator

Note the Package Marking may change over the course of production time without notice

Pin Description

Pin Number	Pin Name	Function
A1	FB	Feedback Analog Input. Connect to the output at the output filter capacitor (Figure 1)
B1	VID1	Output Voltage Control Inputs. Set the output voltage using these digital inputs (see Table
		1). The output defaults to 1.5V if these pins are unconnected.
C1	VID0
D1	SYNC/MODE	Synchronization Input. Use this digital input for frequency synchronization or modulation
		control. Set:
		SYNC/MODE = high for low-noise 600kHz PWM mode
		SYNC/MODE = low for low-current PFM mode
		SYNC/MODE = 500kHz - 1MHz external clock for synchronization to an external clock in
		PWM mode. See Synchronization and Operating Modes in the Device Information section.
D2	EN	Enable Input. For shutdown, set low to SGND.(See Shutdown Mode in the Device
		Information section.)
D3	PGND	Power Ground

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Pin Description (Continued)

Pin Number	Pin Name	Function
C3	SW	Switching Node connection to the internal PFET switch and NFET synchronous rectifier.
B3	PVIN	Power Supply Input to the internal PFET switch. Connect to the input filter capacitor
		(Figure 1).
A3	VDD	Analog Supply Input. If board layout is not optimum, an optional 0.1µF ceramic capacitor
		is suggested (Figure 1)
A2	SGND	Analog and Control Ground

(*) Note that the pin numbering scheme for the Micro SMD package was revised in April, 2002 to conform to JEDEC standard. Only the pin numbers were revised. No changes to the physical location of the inputs/outputs were made. For reference purpose, the obselete numbering had FB as pin 1, VID1 as pin 2, VID0 as pin 3, SYNC as pin 4, EN as pin 5, PGND as pin 6, SW as pin 7, PVIN as pin 8, VDD as pin 9 and SGND as pin 10.

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LM2612BL

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

PVIN, VDD, to SGND	−0.2V to +6V
PGND to SGND	−0.2V to +0.2V
EN, SYNC/MODE, VID0, VID1 to
SGND	−0.2V to +6V
FB, SW	(GND −0.2V) to
	(VDD +0.2V)
Storage Temperature Range	−45˚C to +150˚C

Lead temperature
(Soldering, 10 sec.)	260˚C
Junction Temperature (Note 2)	−25˚C to 125˚C
Minimum ESD Rating
Human body model, C = 100pF, R =
1.5 kΩ	±2kV
Thermal Resistance (θJA)
LM2612ABL/LM2612ATL &
LM2612BBL/LM2612BTL(Note 3)	140˚C/W

Electrical Characteristics

Specifications with standard typeface are for TA = TJ = 25˚C, and those in bold face type apply over the full Operating Temperature Range (TA = TJ = −25˚C to +85˚C). Unless otherwise specified, PVIN = VDD = EN = SYNC = 3.6V, VID0 = VID1 = 0V.

	Symbol	Parameter	Conditions	Min	Typ	Max	Units
	VIN	Input Voltage Range (Note	PVIN = VDD = VID1 = VIN,	2.8		5.5	V
		4)	VID0 = 0V
			VID0 = VIN, VID1 = VIN	1.029	1.05	1.071
	VFB	Feedback Voltage	VID0 = VIN, VID1 = 0V	1.274	1.30	1.326	V
		(Note 5)	VID0 = 0V, VID1 = 0V	1.470	1.50	1.530
			VID0 = 0V, VID1 = VIN	1.764	1.8	1.836
	VHYST	PFM Comparator Hysteresis	PFM Mode (SYNC = 0V)
		Voltage			25		mV
		(Note 6)
	ISHDN	Shutdown Supply Current	EN = 0V		0.02	3	µA
	IQ1	DC Bias Current into VDD	No switching, PFM mode		160	195
			(SYNC/MODE = 0V)
							µA
	IQ2		No switching, PWM mode		605	725
			(SYNC/MODE = VIN)
	RDSON (P)	Pin-Pin Resistance for P			395	550	mΩ
		FET
	RDSON (N)	Pin-Pin Resistance for N			325	500	mΩ
		FET
	RDSON , TC	FET Resistance			0.5		%/C
		Temperature Coefficient
	Ilim	Switch Peak Current Limit	LM2612ABL/LM2612ATL	510	710	850	mA
		(Note 7)	LM2612BBL/LM2612BTL	400	710	980
	VEN_H	EN Positive Going			0.95	1.3	V
		Threshold Voltage
	VEN_L	EN Negative Going		0.4	0.80		V
		Threshold Voltage
	VSYNC_H	SYNC/MODE Positive			0.95	1.3	V
		Going Threshold Voltage
	VSYNC_L	SYNC/MODE Negative		0.4	0.84		V
		Going Threshold Voltage
	VID_H	VID0, VID1 Positive Going			0.92	1.3	V
		Threshold Voltage
	VID_L	VID0, VID1 Negative Going		0.4	0.83		V
		Threshold Voltage
	IVID	VID1, VID0 Pull Down	VID1, VID0 = 3.6V		1.8	3.0	µA
		Current

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Electrical Characteristics (Continued)

Specifications with standard typeface are for TA = TJ = 25˚C, and those in bold face type apply over the full Operating Temperature Range (TA = TJ = −25˚C to +85˚C). Unless otherwise specified, PVIN = VDD = EN = SYNC = 3.6V, VID0 = VID1 = 0V.

Symbol	Parameter	Conditions	Min	Typ	Max	Units
fsync	SYNC/MODE Clock
	Frequency Range		500		1000	kHz
	(Note 8)
FOSC	Internal Oscillator	LM2612ABL/ATL, PWM Mode	468	600	732
	Frequency	(SYNC = VIN)
						kHz
		LM2612BBL/BTL, PWM Mode	450	600	750
		(SYNC = VIN)
Tmin	Minimum ON-Time of P FET			200		nS
	Switch in PWM Mode

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended to be functional, but parameter specifications may not be guaranteed. For guaranteed specifications and associated test conditions, see the Min and Max limits and Conditions in the Electrical Characteristics table. Electrical Characteristics table limits are guaranteed by production testing, design or correlation using standard Statistical Quality Control methods. Typical (Typ) specifications are mean or average values from characterization at 25˚C and are not guaranteed.

Note 2: Thermal shutdown will occur if the junction temperature exceeds the 150˚C maximum junction temperature of the device.

Note 3: Thermal resistance specified with 2 layer PCB(0.5/0.5 oz. cu).

Note 4: The LM2612 is designed for applications where turn-on after system power-up is controlled by the system processor and internal UVLO (Under Voltage LockOut) circuitry is unnecessary. The LM2612 has no UVLO circuitry and should be kept in shutdown by holding the EN pin low until the input voltage exceeds 2.8V. Although the LM2612 exhibits safe behavior while enabled at low input voltages, this is not guaranteed.

Note 5: The feedback voltage is trimmed at the 1.5V output setting. The other output voltages result from the pin selection of the internal DAC’s divider ratios. The precision for the feedback voltages is ±2%.

Note 6: : The hysteresis voltage is the minimum voltage swing on FB that causes the internal feedback and control circuitry to turn the internal PFET switch on and then off during PFM mode.

Note 7: Current limit is built-in, fixed, and not adjustable. If the current limit is reached while the output is pulled below about 0.7V, the internal PFET switch turns off for 2.5 µs to allow the inductor current to diminish.

Note 8: SYNC driven with an external clock switching between VIN and GND. When an external clock is present at SYNC, the IC is forced to PWM mode at the external clock frequency. The LM2612 synchronizes to the rising edge of the external clock.

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LM2612BL

Typical Operating Characteristics LM2612ABL/ATL, Circuit of Figure 1, VIN = 3.6V, TA = 25˚C, L1 = 10 µH, unless otherwise noted.

Quiescent Supply Current vs Temperature

Quiescent Supply Current vs Supply Voltage

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Shutdown Quiescent Current vs Temperature

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Output Voltage vs Temperature (PFM Mode)

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Output Voltage vs Temperature (PWM Mode)

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Output Voltage vs Supply Voltage (VOUT = 1.5V, PWM Mode)

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