Reference Design for the MAX5073 Dual Buck Converter Operating at a Switching Frequency of 2MHz

本文给出了采用 MAX5073双通道降压型转换器、工作于2MHz开关频率下的详细参考设计。该设计可用于电路板空间受限的应用，因为较高的开关频率允许采用更小尺寸的无源元件。此外，该电源解决方案可用于汽车电子(带有抛负载保护)，即需要开关频率工作在AM调频波段以外的产品。例如，汽车仪表盘和信息娱乐系统。

该参考设计的关键规格在下面列出，并给出了应用所需的详细原理图(图1)及材料清单(表1)。

输入电压：5.5V至16V
第1路转换器输出电压 = 3.3V/2A (最大值)
第2路转换器输出电压 = 2.5V/1A (最大值)
每路转换器的开关频率(f_SW) = 2MHz
环境温度(TA) = -40°C至+85°C

图1. MAX5073参考设计

表1. 材料清单
Designator	Value	Description	Part	Footprint	Manufacturer	Quantity
C1	100µF/35	Capacitor	EEVFK1V101P	8mm x 10.2mm	Panasonic	1
C2, C3, C4, C17, C18	0.1µF/25V	Capacitors	GRM188R71E104KA01D	603	Murata	5
CC7, C75	22µF/6.3V	Capaitors	GRM31CR60J226KE19	1206	Murata	2
C8, C9	10µF/25V	Capacitors	GRM31CR61E106KA12	1206	Murata	1
C10, C12	2.2nF	Capacitors	GRM188R71H222JA01	603	Murata	2
C11	560pF	Capacitor	GRM188R71H561KA01	603	Murata	1
C13, C14	22pF	Capacitors	GRM1885C1H220JA01	603	Murata	2
C15	1nF	Capacitor	GRM18871H102KA01	603	Murata	1
C16	4.7µF/6.3V	Capacitor	GRM188R60J475KE19B	603	Murata	1
C19	0.22µF/10V	Capacitor	GRM188R71A224KA01	603	Murata	1
D1, D2	30V, 55mA	Schottky Diodes	MBR0530	SOD123	ON Semiconducort	2
D4	40V, 2A	Schottky Diode	MBRS240	SMB	ON Semiconductor	1
L1, L2	4.7µH	Inductors	IHLP2525-CZ	6.86mm x 6.47mm x 3.18mm	Vishay	1
R1, R11	100kΩ	Resistors	SMD, 1%, 0.125W	603	Vishay	2
R2	6.8Ω	Resistor	SMD, 1%, 0.125W	603	Vishay	2
R3	4.7Ω	Resistors	SMD, 1%, 0.125W	603	Vishay	3
R4, R8, R10	1.18kΩ	Resistors	SMD, 1%, 0.125W	603	Vishay	3
R5, R9	27.4kΩ	Resistors	SMD, 1%, 0.125W	603	Vishay	2
R6	10kΩ	Resistor	SMD, 1%, 0.125W	603	Vishay	1
R7	12.7kΩ	Resistor	SMD, 1%, 0.125W	603	Vishay	1
R12	2.2Ω	Resistor	SMD, 1%, 0.125W	603	Vishay	1
R13	6.9kΩ	Resistor	SMD, 1%, 0.125W	603	Vishay	1
R14	8.76kΩ	Resistor	SMD, 1%, 0.125W	603	Vishay	1
U1	MAX5073	Dual Buck Converter	MAX5073ETI+	32-TQFN_EP (5mm x 5mm)	Analog	1

实际测量电路获得的数据给出了器件的效率指标，详细内容参见表2和表3。

**表2. V_OUT2禁止时的效率指标**
f_SW = 2MHz, L_OUT = 4.7µH, C_OUT = 22µF/6.3V (陶瓷电容)
V_IN (V)	I_IN (A)	V_OUT1 (V)	I_OUT1(A)	Efficiency (%)
14.007	0.065732	3.3371	0.1018	36.8973371
14.010	0.183690	3.3339	0.5122	66.3542117
14.005	0.267750	3.3321	0.8032	71.3722082
14.007	0.329490	3.3309	1.0112	72.9812485
14.005	0.449290	3.3298	1.4007	74.1230723
14.002	0.584520	3.3281	1.8203	74.0201375
14.001	0.650260	3.3267	2.0150	73.6279304

**T表3. V_OUT1禁止时的效率指标**
f_SW = 2MHz, L_OUT = 4.7µH, C_OUT = 22µF/6.3V (陶瓷电容)
V_IN (V)	I_IN(A)	V_OUT2 (V)	I_OUT2 (A)	Efficiency (%)
14.008	0.044533	2.5350	0.1075	43.6845979
14.008	0.067144	2.5337	0.2049	55.1967881
14.003	0.087638	2.5337	0.3010	62.1452787
14.004	0.109076	2.5337	0.4003	66.3986847
14.005	0.133680	2.5337	0.5122	69.3178710
14.005	0.155350	2.5338	0.6097	71.0058542
14.008	0.255976	2.5334	1.0001	70.6597037