ST STOD1317B User Manual

STOD1317B

170 mA 13 V, high efficiency boost converter + LDO

Features

■Operating input voltage range from 2.6 V to 4.8 V

■±1% output voltage tolerance

■Low output ripple

■True-shutdown

■Short-circuit protection

■Digital low power function

■Very high efficiency at light load thanks to pulse skipping operation

■Very fast line and load transients

■1.2 MHz switching frequency

■1 µA max. quiescent current

■DFN12L (3 x 3 x 0.8 mm)

Applications

■Single rail AMOLED display

■Cellular phones

■Battery powered equipment

DFN12L (3 x 3 mm)

integrated and contribute to achieving high efficiency. The true-shutdown feature allows physical disconnection of the battery from the load when the device is in shutdown mode. The control technique is able to maintain efficiency higher than 85% at light loads and higher than 80% at full load. The device includes soft-start control, inrush current limiter, thermal shutdown and inductor peak current limit. The STOD1317B is packaged in DFN12L 3 x 3 x 0.8 mm height.

Description

The STOD1317B is a fixed frequency, high efficiency, boost DC-DC converter with cascaded LDO able to provide output voltages ranging from 6 V to 13 V starting with an input voltage from 2.6 V to 4.8 V. The device is designed to supply loads that are very sensitive to output ripple such as AMOLED display panels. A dedicated LDO is able to suppress any ripple and noise coming out from the DC-DC converter. The LDO works with a constant drop in order to maintain high efficiency

in the whole operating range. The low RDSon N- channel and P-channel MOSFET switches are

Table 1.	Device summary
Order code			Marking	Package	Packaging
STOD1317BPUR			1317B	DFN12L (3 x 3mm)	3000 parts per reel
December 2011			Doc ID 022607 Rev 1		1/22
					www.st.com

Contents	STOD1317B

Contents

1	Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 3
2	Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5
3	Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		6
4	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		7
5	Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . .		9
6	Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		11
	6.1	BOOST multiple mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11

6.1.1 Pulse skipping operation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1.2 Discontinuous conduction mode: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1.3 Continuous conduction mode: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

	6.2	Enable pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
	6.3	Soft-start and inrush current limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
	6.4	Undervoltage lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
	6.5	Overtemperature protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
	6.6	Digital low power function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	13
7	Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		14
	7.1	External passive components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	14

7.1.1 Inductor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1.2 Input and output capacitor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7.2 Recommended PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

8	Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	17
9	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	21

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STOD1317B	Schematic

1 Schematic

Figure 1. Application schematic

	Table 2.	Typical external components
	Comp.	Manufacturer	Part number	Value	Ratings	Size
		MURATA	GRM219R61A106KE44		±10%, X5R, 10V	0805
	CIN	Taiyo Yuden	LMK212BJ106KD-T	10µF	±10%, X5R, 10V	0805
		TDK	C1608X5R0J106		±10%, X5R, 6.3V	0603
	CMID	MURATA	GRM219R61C475KE15	4.7µF	±10%, X5R, 16V	0805
		TDK	C2012X5R1C475		±10%, X5R, 16V	0805
	COUT	MURATA	GRM219R61C475KE15	4.7µF	±10%, X5R, 16V	0805
		TDK	C2012X5R1C475		±10%, X5R, 16V	0805
		CoilCraft	LPS4012-472ML		±20%, curr. 1.7A, resist. 0.175Ω	4.0 x 4.0 x 1.2
	L (1)	TDK	VLS252012T-4R7MR81	4.7µH	±20%, curr. 1.3A, resist. 0.338Ω	2.5 x 2.0 x 1.2
		DASTEK	PNL3008-4R7M		±20%, curr. 0.9A, resist. 0.280Ω	3.1 x 3.1 x 0.8
	R1			kΩ		0402
	R2			kΩ		0402

1.Inductor used for the typical application conditions. Inductance values ranging from 3.3 µH to 6.8 µH can be used together with the STOD1317B. A minimum saturation current of 1.2 A must be ensured to support 170 mA at 2.6 V in full range.

Note:	All the above components refer to a typical application. Operation of the device is not limited
	to the choice of these external components.

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Schematic	STOD1317B

Figure 2. Block schematic

	LX	VMID
	s	s	SCP
	M1	M2	s
			M3
PGND			VOUT
GND			VO_SET
		DMD
	M0
	s		OTA
	PGND
		+	-
			FB
	PWM LOGIC CONTROL		SOFT
	OVP	&
			VREF
		START
	DRIVER
	OCP	+	-
RING			EA
KILLER
	COMP
	+	-
VIN	+
	OSC		SHUT
			OTP
		DOWN
	NC		EN

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STOD1317B	Pin configuration

2 Pin configuration

Figure 3. Pin configuration (top view)
VMID	LX
VOUT	LX
VO_SET	PGND
	AGND
GND	PGND
FB	VIN
EN	NC

Table 3.	Pin description
Pin name		Pin number	Description
VMID		1	Step-up output voltage
VOUT		2	LDO output voltage
VO_SET		3	LDO output voltage set
GND		4	Analog ground
FB		5	Feedback voltage
			Enable pin. Connect this pin to GND or a voltage lower than 0.4V
EN		6	to shut down the IC. A voltage higher than 1.2V is required to
			enable the IC
NC		7	Not connected
VIN		8	Supply voltage
PGND		9, 10	Power ground
LX		11, 12	Switch pin. Inductor connection to the internal switches
Exposed			Internally connected to PGND
PAD

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Maximum ratings				STOD1317B
3	Maximum ratings
Table 4.	Absolute maximum ratings
Symbol		Parameter	Value		Unit
VIN		Supply voltage	-0.3 to +7.0		V
LX		Switching node	-0.3 to +16		V
VOUT_SET		LDO output voltage set	16		V
VOUT		Output voltage	-0.3 to +16		V
EN		Logic pin	-0.3 to 4.6		V
FB		Feedback pin	-0.3 to +2.5		V
ESD		Machine model	±200		V
		Human body model	±2000		V
TAMB		Operating ambient temperature	-40 to 85		°C
TJ		Maximum operating junction temperature	+150		°C
TSTG		Storage temperature	-65 to 150		°C
Note:	Absolute maximum ratings are those values beyond which damage to the device may occur.
	Functional operation under these conditions is not implied.
Table 5.	Thermal data
Symbol		Parameter	Value		Unit
RthJA		Thermal resistance junction-ambient	49.1		°C/W
RthJC		Thermal resistance junction-case (FR-4 PCB)	4.216		°C/W

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STOD1317B	Electrical characteristics

4 Electrical characteristics

TJ = 25 °C, VIN = 3.7 V, VOUT = 10 V, CIN = 2 x 10 µF, CMID = 2 x 4.7 µF, COUT = 2 x 4.7 µF, L = 4.7 µH, VEN = 2 V, unless otherwise specified.

Table 6.		Electrical characteristics
Symbol		Parameter	Test conditions		Min.	Typ.	Max.	Unit
General section
VIN		Operating power input			2.6	3.7	4.8	V
		voltage range
		Shutdown mode	Shutdown mode,			0.5	1	µA
Iq			VEN=GND
		No switching	VEN=VIN=3.7V, VFB=1.3V			1	1.5	mA
VUVLO		Undervoltage lockout	VIN rising			2.4	2.5	V
		threshold	VIN falling		2.1	2.2
fSW		Switching frequency			1	1.2	1.35	MHz
IPK		Switch current limitation			1.6	2	2.4	A
Output voltage (VOUT)
VFB		Feedback voltage	TA=25°C		1.08	1.2	1.32	V
VFB		Accuracy	-40°C<TA<85°C		1.02		1.38	V
VOUT		Output voltage range			6	10	13	V
VLINE/LOA		Total line/load static	TA=25°C; VIN=2.6V to			30	40	mV
D		variation (1)	4.8V; I	=5mA to 170mA
			OUT
VOUT		Output voltage ripple	VIN=3.7V, VOUT=10V,				30	mV
RIPPLE			IOUT=10mA
VOVP		Overvoltage protection	VFB=0		14	15	16	V
ILKFB		FB pin leakage current	VFB=5V to 13V				1	µA
VMID		Step-up output voltage			VOUT +	VOUT +	VOUT +	V
		regulation			0.38	0.56	0.7
Logic inputs
VIL		EN low-level input voltage					0.4	V
VIH		EN high-level input voltage			1.2			V
ILK-I		EN input leakage current	VEN=VIN=4.8V				1	µA
Power switches
RDSON		P-Channel ON resistance	ISW_P=100mA			550	900	mΩ
		N-Channel ON resistance	ISW_N=100mA			250	400
ILKG-LX		LX leakage current	VIN=VLX=4.8V; VEN=0				1	µA

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