七,功能概述
Inductor Value Calculation
The operating frequency and inductor selection are inter-related in that higher operating frequencies permit the
use of a smaller inductor for the same amount of inductor ripple current. However, this is at the expense of efficiency
due to an increase in MOSFET gate charge losses. The equation (2) shows that the inductance value has a direct
effect on ripple current.
Accepting larger values of ripple current allows the use of low inductances, but results in higher output voltage ripple

Layout Consideration
In high power switching regulator, a correct layout is im-portant to ensure proper operation of the regulator. In
general, interconnecting impedance should be minimized by using short, wide printed circuit traces. Signal and
power grounds are to be kept separating and finally com-bined using ground plane construction or single point
grounding. Figure 2 illustrates the layout, with bold lines indicating high current paths. Components along the bold
lines should be placed close together. The following is a checklist for your layout:
1. Firstly, to initial the layout by placing the power components. Orient the power circuitry to achieve a clean
power flow path. If possible, make all the connections on one side of the PCB with wide, copper filled areas.
2. In Figure 2, the loops with the same color bold lines conduct high slew rate current. These interconnecting
impedances should be minimized by using wide, short printed circuit traces.
3. Keep the sensitive small signal nodes (FB, COMP) away from switching nodes (LX or others) on the PCB.
Therefore, place the feedback divider and the feedback compensation network close to the IC to avoid switching
noise. Connect the ground of feedback divider directly to the GND pin of the IC using a dedicated ground trace.
4. The VCC decoupling capacitor should be right next to the VCC and GND pins. Capacitor C2 should be connected
as close to the VIN and UGND pins as possible.
5. Place the decoupling ceramic capacitor C1 near the VIN as close as possible. The bulk capacitors C8 are also
placed near VIN. Use a wide power ground plane to con- nect the C1, C8, and C4 to provide a low impedance

八,相关产品

Part_No	Package & Pins	Topology	Architecture	No. of PWM Outputs	Drive Lout (A)	Vin (V)		Fmax(Khz)	Vref (V)	R-Top (milohm)	R-Sync (milohm)	Iq (No load) (uA)
						min	max
jtma7083	TQFN5x6-28	Buck	CM	1	5	4.5	26	380	0.8	50	20	1000
jtma7085	SOP-8	Buck	CM	1	2	4.5	26	380	0.8	100		1000
jtma7089	SOP-8P	Buck	CM	1	4	4.5	26	380	0.8	80		1000
jtma7104	SOT-23-5	Buck	CM	1	1	2.7	6	1500	0.6	280	250	25
	TSOT-23-5
jtma7104A	SOT-23-5	Buck	CM	1	1	2.7	6	1500	0.6	280	250
jtma7142	SOP-8	Buck	CM	1	3	4.3	14	500	0.8	70	70	500
jtma7145	SOP-8P	Buck	CM	1	3	4.3	14	500	0.8	55	45	500
jtma7153B	TDFN3x3-10				3	2.6	5.5	2000	0.8	110	110	460
jtma7176	TDFN3x3-10	Buck	CM	2	1	2.7	6	1500	0.6	280	250	500
jtma7176A	TDFN3x3-10	Buck	CM	2	1	2.7	6	1500	0.6	280	250
jtma7178	TDFN2x2-6	Buck	CM	1	1	2.7	6	1500	0.6	280	250	25
jtma7178A	TDFN2x2-6	Buck	CM	1	1	2.7	6	1500	0.6	280	250
jtma7179	TDFN3x3-12	Buck	CM	2	1	2.7	6	1500	0.6	280	250	25
jtma7179A	TDFN3x3-12	Buck	CM	2	1	2.7	6	1500	0.6	280	250
jtma7290	TDFN2x2-8		CM	1	1	3.3	8	1500	0.6	280	250	25
jtma7300	SOP-8	Buck	CM	1	2	4.5	24	340	0.925	110	110	1900
jtma7301	SOP-8P	Buck	CM	1	3	4.5	24	340	0.925	110	110	1900
jtma7302	SOP-8	Buck	CM	1	2	4.5	24	340	0.92	130	130	1900
jtma7302B	SOP-8P	Buck	CM	1	2	4.5	24	340	0.92	130	130	1900
jtma7303	SOP-8P	Buck	CM	1	3	4.5	24	340	0.92	85	85	1900
jtma7304	SOP-8P	Buck	CM	1	4	4.5	24	340	0.8	85	85	1900
jtma7311	SOP-8P	Buck	CM	1	3	4.5	24	1300	0.925	110	110	1900
jtma7312	SOP-8	Buck	CM	1	2	4.5	24	340	0.925	110	110	1900
jtma7313	SOP-8P	Buck	CM	1	3	4.5	24	340	0.925	110	110	1900
jtma7314	TSOT-23-8	Buck	CM	1	2	4.5	24	500	0.8	150	70	500
jtma7322	SOP-8P	Buck	CM	1	2	2.5	6	1000	0.8	85	75	460
	TDFN3x3-10
jtma7323	SOP-8P	Buck	CM	1	3.2	2.5	6	1000	0.8	85	75	460
	TDFN3x3-10
jtma7324	SOP-8P	Buck	CM	1	4	2.5	6	500	0.8	85	75	460
	TDFN3x3-10
jtma7325	SOP-8P	Buck	CM	1	5	2.5	6	1000	0.6	65	55	460
jtma7334	SOP-8	Buck	CM	1	2	4.5	24	340	0.8	110	110	1900
jtma7335	SOP-8P	Buck	CM	1	3	4.5	24	340	0.8	110	110	1900
jtma7336	TDFN3x3-10	Buck	CM	1	2	4.5	24	340	0.8	110	110	1900
jtma7337	TDFN3x3-10	Buck	CM	1	3	4.5	24	340	0.8	110	110	1900
jtma8713	TQFN4x4-23	Buck	COT	1	6	2.7	28	100~1000	0.8	30	9	750
jtma8802	TQFN5x6-28	Buck	COT	1	8	3	25	500	0.75	12	12	400
jtma8804	TDFN3x3-10	Buck	CM	1	3	2.6	6	1000	0.6	65	55	460
jtma8805	TDFN3x3-10	Buck	CM	1	3	2.6	6	1000	0.6	75	55	460
jtma8807	TQFN3x3-16	Buck	COT	1	8	6	28	500	0.6	24	14	80
jtma8824	TSOT-23-6	Buck	CM	1	1	2.7	5.5	1500	0.6	280	250	25
jtma8835	TDFN3x3-10	Buck	CM	1	3	4.5	24	600	0.8	70	70	400
jtma7414	TSOT-23-8A	Buck	CM	1	2	4.5	24	500	0.788	150	70	1000
jtma7319	TSOT-23-8A	Buck	CM	1	2.5	4.5	24	500	0.807	140	60	1000
jtma8715	TQFN 4x4 23	Buck	COT	1	6	2.7	28	100~1000	0.8	30	12	700
jtma8716A	TQFN 5x5 30	Buck	COT	1	12	2.7	28	300~1000	0.8	14.6	7.8	750
jtma8715	TQFN 4x4 23	Buck	COT	1	6	2.7	28	100~1000	0.8	30	12	700
jtma8805B	TDFN 3x3 10	Buck	CM	1	3	2.6	6	1000	0.8	75	55	460
jtma8805A	TDFN 3x3 10	Buck	CM	1	3	2.6	6	1000	0.8	75	55	460